Which supplements actually have evidence behind them? Understanding what a bottle is in Hong Kong law, the Department of Health's own list, and what the large trials found

TL;DR This article will not tell you what to take or not take. It does two things: it sets out what a bottle of supplements is in Hong Kong law, and it lists, substance by substance, what the large randomised trials actually found — including the ones that found nothing, because your money was spent all the same. The one thing a Hong Kong reader should know: the Department of Health's Drug Office maintains a public, searchable, bilingual list of slimming products with undeclared Western drug ingredients, whose earliest record goes back to 1998. That page carries 845 dated records, running from 1998-02-19 to 2026-03-19, of which 81 are marked as Hong Kong (73 marked 「[香港]」 and 8 marked 「[HK]」) — those three figures are counts made on that page, the Drug Office itself publishing no total there. The most glaring pair of facts is one the government states in a single passage of its own: pharmaceutical products containing sibutramine have been prohibited from use and sale in Hong Kong since November 2010 — and in May 2025 the Department of Health was still able to buy a slimming product containing sibutramine on a social media platform. Fourteen and a half years after the ban, it was still on sale. The biggest misconception is that a supplement must do some good and at worst does nothing. It is not so. Beta-carotene supplements increased lung cancer in smokers in two large trials; and on 21 June 2022 the United States Preventive Services Task Force (USPSTF) gave beta-carotene and vitamin E supplements for the prevention of cardiovascular disease or cancer a grade D (recommends against use). On vitamin D, the VITAL trial of 25,871 people with a median follow-up of 5.3 years found no effect at all on either of its two primary endpoints, cancer and cardiovascular disease. Red yeast rice is pharmacologically a statin. The Department of Health states in its own Chinese that the lactone form of monacolin K 「於化學上與名為『洛伐他汀』的藥物完全相同」 — is chemically identical to the drug called lovastatin — and statins are prescription drugs under the Pharmacy and Poisons Ordinance (Chapter 138). This article does not deal with prices (the reason is at the end), does not assess brands, and will not tell you to start or stop any supplement. If you are on medication, have a long-term condition, are pregnant or are planning a pregnancy, what suits you is for a doctor or a pharmacist to decide on your circumstances, not something an article can decide.

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#In Hong Kong, what is a bottle of supplements in law?

Hong Kong law does not classify by the label "supplement" but by what the product is represented as doing — and that point governs the rest of this article.

The Drug Office of the Department of Health's Basic knowledge of registered drugs (August 2024, bilingual) states that drugs fall into two classes, Chinese medicines and non-Chinese medicines, and the same page carries the statutory definition of a "pharmaceutical product". [Note 1]

In one sentence: the dividing line is not only what it says it does, but what it can actually be used for. A product represented as treating or preventing disease falls within Chapter 138 and must be registered with the Pharmacy and Poisons Board of Hong Kong; but the definition has a second limb — a product that may be used or administered to human beings with a view to restoring, correcting or modifying physiological function by pharmacological, immunological or metabolic action, or to making a medical diagnosis, falls within the definition too, regardless of how it packages itself on the label or in advertising. A product sold as a food or as general nutrition does not automatically fall outside the definition merely by being presented that way; if what it actually does meets the second limb, it falls back within Chapter 138.

What registration itself requires is on the same page: a pharmaceutical product must meet the standards of safety, efficacy and quality before it can be registered under the regulations. And how a consumer actually tells: the Board gives a registered drug a registration number in the format HK-XXXXX, and that number must be shown on the drug label. [Note 2]

⚠️ Among the Hong Kong government documents found for this article, not one contains a sentence of the form "health supplements do not require registration", so this article does not write one either. The definition above says what it says: whether registration is required turns on whether the product falls within the definition of a "pharmaceutical product", not on whether the shelf calls it a supplement or a health product.

Who this section is most use to: anyone who sees a "health product" claiming to treat or prevent some disease. That claim is itself what pushes the product towards the Chapter 138 side — and on that side an HK-XXXXX number is mandatory. A therapeutic claim without a number is a contradiction between two things.

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#Where can the government's own list be found? And Hong Kong is on it

The Drug Office of the Hong Kong Department of Health maintains a standing, searchable, bilingual public list, "Slimming Products with Undeclared Western Drug Ingredients", whose records run from 1998 to the present. It is a ready-made consumer tool, not a research report.

The list sits under the Drug Office's section on using slimming products with care (the English version headed "Slimming Products with Undeclared Western Drug Ingredients"). The whole table loads at once, one date per row, a product name, and (on some rows) a region tag — of the 845 rows, 169 carry no region tag, with dates between 1998-02-19 and 2013-05-16; the Chinese and English versions agree on that figure.

⚠️ This line has to be spelled out, because the government's own page has a typesetting error. In the Chinese version the record dated 2017-06-20 (7-Days Herbal Slim-Extra) is written in the raw HTML as [澳洲<br> — the closing bracket is missing — while the same row in the English version reads [Australia] properly. A program reading the tag by […] treats that row as having no region tag, so the Chinese version counts 170 rows without a tag and an upper date of 2017-06-20, while the English version counts 169 and an upper date of 2013-05-16. The truth is 169 rows, 1998-02-19 to 2013-05-16; that row is Australia, and only the tag is misprinted. This article writes the result on which the two versions agree, and states the source's own typesetting error rather than quietly correcting a number.

Beyond the numbers there is one fact that needs no denominator: a Hong Kong government department has long maintained a public record of slimming products found to contain undeclared Western drug ingredients, in both languages side by side. That fact is itself an answer to the question of how clean this market is.

#Two Hong Kong cases with a word-for-word record

Case one — 23 May 2025: a drug banned for fourteen and a half years, bought on a Hong Kong social media platform. Acting on intelligence, the Department of Health purchased a slimming product on a social media platform, and analysis showed the sample to contain sibutramine and furosemide; and pharmaceutical products containing sibutramine have been prohibited from use and sale in Hong Kong since November 2010. [Note 3]

Put differently: the ban took effect in November 2010, and in May 2025 the Department of Health was still able to buy a product containing that ingredient. Those two sentences are in the same passage of official text; this article has not forced them together.

⚠️ The instructions to stop taking the product are asymmetric between the two press releases, and this article will not treat the two as one passage. The release of 29 January 2026 tells people to stop taking it in two places: once at the head of the paragraph about the risks of buying online, and once in the second-to-last paragraph. The release of 23 May 2025, in the paragraph occupying the corresponding position (also opening 「衞生署強烈呼籲」), carries no instruction to stop, reading instead 「衞生署強烈呼籲市民切勿購買或服用成分或來歷不明的產品。」 — the Department strongly urges the public not to buy or take products of unknown composition or origin. That is to say, the two releases are asymmetric on this point: the 2026 one says it twice and the 2025 one once. [Note 3] [Note 4]

The second-to-last paragraphs of the two releases are the pair that do the same work and can be read word against word, and there are three printed differences between them. How the product is referred to: the 2025 one says 「相關」 and the 2026 one 「上述」. What triggers the action: the 2025 one says 「如有疑問或服用後感到不適」 and the 2026 one 「如服用有關產品後感到不適」 — the former counting mere doubt as well. The register: the former says 「立即徵詢」 and the latter 「尋求」. The action in the two paragraphs is the same (stop at once, find a healthcare professional, and the product may be submitted for disposal); how the product is referred to, what triggers it and the register are not entirely the same.

Case two — 29 January 2026: a "premium Korean" slimming product found to contain two prescription drugs. The Department of Health was investigating a case of the illegal online sale of a slimming drug containing undeclared controlled drug ingredients, the sample being found to contain hydrochlorothiazide and fluoxetine. [Note 5] Which is to say: someone buying a slimming product was in fact taking a blood pressure drug and an antidepressant, with nothing about it on the packaging. The same release also set out the risks of buying controlled drugs online. (The two characters 「冷鍵」 as printed in that release are reproduced here as found, without alteration.)

On penalties, the same release states that the illegal sale of unregistered pharmaceutical products or Part 1 poisons is a criminal offence carrying a maximum penalty of a fine of a hundred thousand dollars and two years' imprisonment; and that Part 1 poisons may be sold only on prescription, in registered pharmacies and under the supervision of a registered pharmacist. [Note 6]

Which is to say: what was found in the two cases above has to be dealt with separately and cannot be lumped together. The hydrochlorothiazide and fluoxetine of case two are Part 1 poisons, and there is only one lawful way to sell them in Hong Kong — on a doctor's prescription, in a registered pharmacy and under a registered pharmacist's supervision. But the sibutramine of case one is not like that: since November 2010, pharmaceutical products containing sibutramine have been prohibited outright from use and sale in Hong Kong — that is, for this ingredient there is not even a route of buying it at a pharmacy on a prescription. Neither social platforms nor instant messaging apps appear on any lawful list at all.

⚠️ The Chinese and English versions of the same release diverge on this sentence, and in both directions. The English has 「or possession」 where the Chinese does not; the Chinese has 「一經定罪」 — on conviction — where the English does not. This article reproduces both and does not use one version to fill in the other. (The other release, of 23 May 2025, does have 「或管有」 in Chinese, and the two versions agree there.)

Who this section is most use to: anyone buying slimming products through social platforms, instant messaging apps or a buying agent. What the two cases above have in common is not where the products came from but the channel they were bought through — both times it was the Department of Health buying online itself.

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#Hong Kong has its own "how many IU needs a prescription" threshold — and it is not the same thing as the doses in the overseas trials

The Drug Office of the Hong Kong Department of Health publishes a list of vitamin products that are prescription drugs, with the dose thresholds marked. That is a legal classification and not nutritional advice — the two are easily confused, and this section is about prising them apart.

The Drug Office's vitamins page (December 2024, bilingual) lists six items, including vitamin A at a daily dose of not less than 10,000 international units and vitamin D at a daily dose of more than 1,000 international units. [Note 7]

⚠️ That list is not exhaustive. It is introduced by the words "for example", which are the Department's own; whether there are vitamin products that are prescription drugs beyond the list is not stated on that page.

⚠️ And one more thing: items (a) to (f) above are not a free-standing legal list on the original page. They are the sixth of the seven items in a consumer checklist on buying vitamins. All seven items of the checklist, together with the Department's own two closing sentences immediately following, are reproduced in the notes. [Note 8] Item 1 is the first sentence of the whole checklist, and what it asks is not "which one to take" but whether to take one at all; and item 2 is the only one telling you to look at the ingredients and the amounts and to seek professional advice from a healthcare professional. Those two are the easiest to skip, and on the original page they come first.

#Two things that must be kept apart

The section below deals with the VITAL trial, which used vitamin D₃ at 2,000 IU a day; and the threshold at item (c) above is a "pharmaceutical product" at a daily dose of more than 1,000 international units. Putting those two numbers side by side invites a wrong conclusion, so this article spells it out:

• Item (c) governs the class of pharmaceutical products — that is, products falling within the Chapter 138 definition of the previous section. Whether a product on a shelf is a "pharmaceutical product" has to be judged on that definition.
• VITAL's 2,000 IU a day is a trial dose in an American research programme, not a Hong Kong legal classification.
• So this article does not, and cannot, say that a Hong Kong retail product labelled 2,000 IU is unlawful or must be bought on prescription. That judgment is not one an article can make.

A comparison, not a calculation: the same number, 10,000 IU of vitamin A, means something entirely different in the hands of the two bodies. The Hong Kong Department of Health uses it as a legal classification threshold; the United States National Institutes of Health Office of Dietary Supplements (NIH ODS, updated 10 March 2025) uses it as a threshold for advice to pregnant women — experts advise that women who are pregnant, who might be pregnant and who are breastfeeding should not take vitamin A supplements above 3,000 mcg RAE (10,000 IU) a day, and that advice exists to prevent birth defects, the sites of the malformations it lists immediately afterwards being the eyes, the skull, the lungs and the heart. Both are 10,000 IU, but one is a legal category and the other clinical advice.

Who this section is most use to: anyone buying high-dose vitamin D or vitamin A online. What you are buying may fall within the class of "pharmaceutical products" in Hong Kong, and that classification is not decided by you or by the seller but by how the product is represented and by the statutory definition.

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#Why does an argument that makes sense not mean it works? The lesson of beta-carotene

The supplement industry's strongest selling point has never been a trial result but an argument that makes sense. The history of beta-carotene is the complete story of an argument that made sense being overturned by two large trials — and overturned in the direction of harm, not of no effect.

The argument at the time was: smokers get more lung cancer, people who eat more fruit and vegetables get less lung cancer, fruit and vegetables contain beta-carotene, so supplementing beta-carotene ought to reduce lung cancer. So two trials were done.

ATBC (Finland, 29,133 male smokers aged 50 to 69, alpha-tocopherol 50 mg a day and/or beta-carotene 20 mg a day, followed for 5 to 8 years, 876 new lung cancers in all): those taking beta-carotene had an 18% higher incidence of lung cancer and 8% higher total mortality. [Note 9]

⚠️ Note this: the same trial and the same abstract recorded, back in 1994, both fewer cases of prostate cancer and more deaths from haemorrhagic stroke in the alpha-tocopherol arm. Seventeen years later SELECT recorded vitamin E increasing the risk of prostate cancer (see below), and Schürks 2010 recorded an increase in haemorrhagic stroke. The direction of a secondary signal in an early trial cannot be taken for the conclusion of the large trials that follow.

CARET (18,314 smokers, former smokers and asbestos-exposed workers, beta-carotene 30 mg a day plus retinyl palmitate 25,000 IU a day, mean follow-up 4.0 years): the relative risk of lung cancer in the active treatment arm was 1.28, and the trial was stopped 21 months early because the results were so bad. [Note 10] ⚠️ Those three mortality figures are the substance of the phrase "the direction is harm". A rise in incidence and a rise in mortality are two different things; CARET had both.

In one sentence: a trial was halted 21 months early because the results were so bad. That is not "the effect was not significant"; it is the opposite direction. USPSTF (21 June 2022) put that history into a single sentence: it recommends against the use of beta-carotene supplements for the prevention of cardiovascular disease or cancer. [Note 11]

Who this section is most use to: anyone who sees a claim that "research shows this ingredient is linked to that disease". Beta-carotene had exactly that chain of evidence — an observational association plus a plausible mechanism. The trials came out the other way. An observational association is not the same as supplementation working, and neither is the same as supplementation being safe; those are three separate things.

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#What did the large randomised trials actually find?

This is the dullest and the most important section in the article: trial by trial, the numbers in each arm, and the two results. Most of the answers are zero — and zero is what this section is about, because the money was spent all the same.

#Vitamin D — VITAL: cancer, cardiovascular disease and fracture, three zeros

VITAL was a nationwide American randomised, placebo-controlled, 2×2 factorial trial: vitamin D₃ 2,000 IU a day and/or marine n-3 fatty acids 1 g a day; men aged 50 or over and women aged 55 or over; 25,871 people randomised (including 5,106 black participants), median follow-up 5.3 years. The result: compared with placebo, supplementary vitamin D₃ did not lower the incidence of invasive cancer or of cardiovascular events. The same people were followed up for fracture (LeBoff et al, NEJM 2022): 769 of 12,927 in the vitamin D arm had a fracture against 782 of 12,944 on placebo, a hazard ratio of 0.98. [Note 12]

⚠️ The same abstract has one more sentence immediately after the fracture figures, answering the question whether people who are low in vitamin D to begin with get more out of supplementing: treatment effects did not differ by baseline characteristics, including the serum 25-hydroxyvitamin D level. [Note 12]

⚠️ The scope limitation at the end of the conclusion is the point: the population of this trial was not people with diagnosed vitamin D deficiency or osteoporosis. This trial cannot answer the question for that group. But two things have to be kept apart: "did not recruit people with diagnosed deficiency" is not the same as "did not analyse by baseline level" — the sentence above states that it did look by baseline serum 25-hydroxyvitamin D and saw no difference.

Do the arithmetic once (the absolute fracture figures): using the numbers in that same sentence. The vitamin D arm: 769 ÷ 12,927 = 5.95%; the placebo arm: 782 ÷ 12,944 = 6.04%. Over a median follow-up of 5.3 years, the two arms differ by 0.09 percentage points. That is what "a hazard ratio of 0.98" looks like in absolute numbers.

#The other side of vitamin D: no effect and harm are stories about two different doses

⚠️ Do not run the following two sets of trials together. VITAL's 2,000 IU a day gave a result of zero; the harm appears with very large doses given once a year or once a month:

• Sanders et al (JAMA 2010): 2,256 community-dwelling women aged 70 or over at high risk of fracture, given a single oral dose of 500,000 IU of cholecalciferol each autumn or winter for 3 to 5 years. The vitamin D arm had 171 fractures against 135 on placebo; the fall rate was 83.4 against 72.7 per 100 person-years, an incidence rate ratio of 1.15 (95% CI 1.02–1.30, P=.03); and the fracture incidence rate ratio was 1.26 (95% CI 1.00–1.59, P=.047). ⚠️ The same abstract has two more sentences immediately afterwards, and they are the mechanism of that result: a post hoc analysis of falls observed a temporal pattern — the incidence rate ratio for falls in the vitamin D arm against placebo was 1.31 in the first three months after dosing and 1.13 in the subsequent nine months (test of homogeneity P=.02). That is to say, the harm is concentrated in the three months after the annual dose. And as to the population: in a substudy the median baseline serum 25-hydroxycholecalciferol was 49 nmol/L, with fewer than 3% below 25 nmol/L — that is, these women were not vitamin D deficient. The authors conclude that a single high annual oral dose of cholecalciferol increased the risk of falls and fractures. ⚠️ That paper carries an erratum (Erratum in JAMA. 2010 Jun 16;303(23):2357). This article has not obtained the content of that erratum (paywalled, not carried in PMC), and therefore does not know whether it touches any of the figures above — this article states that rather than pretending it does not exist.
• Bischoff-Ferrari et al (JAMA Intern Med 2016): 200 people aged 70 or over who had had a fall, followed for 1 year. ⚠️ One thing about the baseline first: 116 of the 200 (58.0%) were vitamin D deficient at baseline (below 20 ng/mL) — that is, this trial was not done in a vitamin D replete population. ⚠️ And something that matters more: falls were a secondary endpoint, not a primary one. The primary endpoints were improvement in lower extremity function and achieving a 25-hydroxyvitamin D level of at least 30 ng/mL at 6 and 12 months; monthly self-reported falls were a secondary endpoint. The fall figures: an incidence of 66.9% in the 60,000 IU arm and 66.1% in the 24,000 IU plus calcifediol arm against 47.9% in the 24,000 IU arm (P=.048). The authors' conclusion, in full, is that although higher monthly doses of vitamin D were effective in reaching a threshold of at least 30 ng/mL of 25-hydroxyvitamin D, they had no benefit on lower extremity function and were associated with an increased risk of falls compared with the 24,000 IU arm. ⚠️ This is a secondary endpoint inside a trial whose primary endpoints were zero.

Which is to say: "vitamin D does nothing" and "vitamin D is harmful" are two different sentences, each attaching to a different dosing regimen, and neither can stand in for the other.

#Fish oil (omega-3) — the same VITAL trial, and the same two zeros

Over the median follow-up of 5.3 years, major cardiovascular events occurred in 386 people in the n-3 arm against 419 on placebo, a hazard ratio of 0.92 (95% CI 0.80–1.06); the authors conclude that supplementation did not lower the incidence of major cardiovascular events or of cancer compared with placebo. [Note 13]

⚠️ In the same abstract, the hazard ratio for the secondary endpoint of total myocardial infarction is 0.72 (95% CI 0.59–0.90). That figure is often quoted on its own. It is a secondary endpoint inside a trial whose primary endpoints were both zero — and it is not a lone secondary endpoint either, but one of six in the same sentence. Picking out the best one is exactly how this trial is usually quoted in popular accounts. [Note 13]

In one sentence: of the six secondary endpoints, only one is favourable. And the last one — no additional bleeding risk — is a safety result that anyone taking fish oil actually wants to know and that popular accounts rarely give. This article prints both sides and leaves the reader to weigh them.

#Multivitamins — COSMOS

21,442 American adults (12,666 women aged 65 or over and 8,776 men aged 60 or over), without major cardiovascular disease or recently diagnosed cancer; the intervention period ran from June 2015 to December 2020; median follow-up 3.6 years. No significant effect on invasive cancer, on cardiovascular events or on all-cause mortality. [Note 14]

⚠️ In the same abstract there are three site-specific secondary outcomes in all, and this article lists all three: breast cancer 1.06 (95% CI 0.79–1.42), colorectal cancer 1.30 (95% CI 0.80–2.12) and lung cancer 0.62 (95% CI 0.42–0.92). All three are site-specific secondary outcomes inside a trial whose primary outcomes were zero, and picking out either side on its own is misleading. The same abstract also states that there were no safety concerns.

#Calcium with vitamin D — WHI, and two figures inside the same abstract

36,282 postmenopausal women aged 50 to 79, given 1,000 mg of calcium plus vitamin D₃ 400 IU a day, mean follow-up 7.0 years. ⚠️ The salt form of the calcium has to be stated, because the outcome in this section is kidney stones: the abstract states that calcium carbonate was used. (The [corrected] in that sentence is a correction marker printed by the PubMed abstract itself; the paper also carries an erratum, Erratum in N Engl J Med. 2006 Mar 9;354(10):1102, whose content this article has not obtained, so what it touches is not known.)

Hip bone density was 1.06% higher in the supplemented arm, the intention-to-treat hazard ratio for hip fracture was 0.88 (0.72–1.08), and the hazard ratio for kidney stones was 1.17 (1.02–1.34). ⚠️ This article reports a conflict and does not adjudicate it. The same abstract also carries a sensitivity analysis: with the data of non-adherent participants censored, the hazard ratio for hip fracture is 0.71 (0.52–0.97). The second figure is the trial's sensitivity analysis, not the trial's result. Both are in the same abstract and this article prints both. [Note 15]

⚠️ The sentence immediately after answers a question many people will ask: the effect did not differ significantly by baseline vitamin D or calcium intake. Put differently: whether people who were lower in vitamin D to begin with got more out of it was looked at in this trial, and the answer was no significant difference. The LeBoff fracture trial above gives the same answer on the same point. Two trials, two outcomes, and in neither did the baseline vitamin D level change the result. That is a different thing from "did not recruit people with diagnosed deficiency or osteoporosis" — the latter is the recruitment scope and the former an analytical result, and neither can stand in for the other.

#Vitamin E and selenium — SELECT, one trial reported twice with two conclusions

SELECT randomised 35,533 people to vitamin E 400 IU a day and selenium 200 micrograms a day. Note that the two reports below use 99% confidence intervals, not 95%.

• The first report of 2009 (Lippman et al, median follow-up 5.46 years): the hazard ratios for prostate cancer were vitamin E 1.13 (99% CI 0.95–1.35, n=473), selenium 1.04 (0.87–1.24, n=432) and selenium plus vitamin E 1.05 (0.88–1.25, n=437), against placebo 1.00 (n=416). No significant differences were seen in any other prespecified cancer endpoint (all P>.15); and non-statistically-significant increases were recorded in the risk of prostate cancer in the vitamin E arm (P=.06) and in the risk of type 2 diabetes in the selenium arm (relative risk 1.07, 99% CI 0.94–1.22, P=.16). The conclusion was that selenium or vitamin E did not prevent prostate cancer at the doses and formulations used.
• The re-report of 2011 (Klein et al): against 529 men diagnosed with prostate cancer in the placebo arm, 620 were diagnosed in the vitamin E arm, a hazard ratio of 1.17 (99% CI, 1.004-1.36, P = .008); the absolute increase in prostate cancer risk per 1,000 person-years was 1.6 for vitamin E, 0.8 for selenium and 0.4 for the two combined. The conclusion was that dietary supplementation with vitamin E significantly increased the risk of prostate cancer among healthy men.

⚠️ This article reports a conflict and does not adjudicate it: the same trial concluded in 2009 that it did not prevent, and after longer follow-up in 2011 the vitamin E arm reached statistical significance. Both use 99% confidence intervals, and they must not be relabelled 95%. It also has to be said plainly: the 2009 report is not a clean zero. Its own abstract states that prostate cancer risk in the vitamin E arm was raised at P=.06, only short of the threshold they used. "Not statistically significant" and "no effect" are two different sentences. And the selenium arm recorded a non-significant increase in the risk of type 2 diabetes in 2009 — this article lists it because, among the results reported in that 2009 abstract, it is the only safety signal about selenium; it is listed not because it concludes anything, the authors themselves having marked it as not statistically significant.

#High-dose vitamin E — mortality and stroke

• Miller et al (Ann Intern Med 2005), 19 trials and 135,967 participants, at doses of 16.5 to 2,000 IU a day (median 400 IU a day). ⚠️ The "39 per 10,000 people" below is not calculated from those 19 trials and 135,967 people — it is the pooled result of the high-dose subset, and that abstract states for itself that the subset is 11 trials: of the 11 trials testing high-dose vitamin E (400 IU a day or more), 9 recorded an increased risk of all-cause mortality. That abstract does not state how many people those 11 trials contain between them, and this article will not estimate it. The subset result is 39 per 10,000 people (95% CI 3 to 74, P=0.035); and the authors conclude that high-dose vitamin E supplements may increase all-cause mortality and should be avoided. ⚠️ The same passage has two more sentences, and they are the bounds on either side: the risk difference in the low-dose vitamin E trials was −16 per 10,000 people (95% CI −41 to 10, P>0.2); and a dose-response analysis showed a statistically significant relationship between the dose of vitamin E and all-cause mortality, with the increase in risk appearing above 150 IU a day. That figure is far below the 400 IU of the headline. ⚠️ The authors' own statement of limitations has to be given with it: the high-dose trials were mostly small and were conducted in patients with chronic disease; whether these results generalise to healthy adults is uncertain, and the threshold at which the risk begins to rise is difficult to estimate precisely.
• Schürks et al (BMJ 2010), 9 trials and 118,765 participants (59,357 on vitamin E against 59,408 on placebo); the inclusion criteria were randomised, placebo-controlled trials with follow-up of 1 year or more. ⚠️ But the three pooled estimates below are not all calculated from the 9 trials: seven trials reported data on total stroke, and haemorrhagic and ischaemic stroke had five trials each. Take first the result that governs the whole passage: vitamin E had no effect on the risk of total stroke, with a pooled relative risk of 0.98 (95% CI 0.91–1.05), P=0.53. Only then come the results split by type of stroke: the risk of haemorrhagic stroke rose, with a pooled relative risk of 1.22 (1.00–1.48), P=0.045; and the risk of ischaemic stroke fell, with a pooled relative risk of 0.90 (0.82–0.99), P=0.02. The paper itself puts the two sides into one sentence: 「In terms of absolute risk, this translates into one additional haemorrhagic stroke for every 1250 individuals taking vitamin E, in contrast to one ischaemic stroke prevented per 476 individuals taking vitamin E.」 The first sentence of the authors' conclusion is precisely why total stroke cannot be looked at alone: this pattern of one rising and one falling is masked when only total stroke is examined. And their reasoning is written plainly: given that the reduction in the risk of ischaemic stroke is relatively small while haemorrhagic stroke is generally the more serious in its consequences, the indiscriminate widespread use of vitamin E should be cautioned against.

#The official grade: the USPSTF 2022 recommendation summary table, all three rows

⚠️ The task force defines the scope of that recommendation very clearly for itself: it applies to community-dwelling, non-pregnant adults, and expressly excludes children, pregnant women, people with chronic disease, hospital inpatients and people with known nutritional deficiency; and it separately recommends folic acid for those planning a pregnancy. [Note 16]

Which is to say: the generalisation "supplements do nothing" is wrong. What that document is about is healthy adults taking supplements to prevent cardiovascular disease and cancer, and no more than that.

⚠️ And: two grade I ratings (insufficient evidence) do not mean "do not take it", and the task force sets out how to handle it in the "How to implement this recommendation?" section of the same page. [Note 16] Grade D and grade I are two different sentences: D means do not use it, and I means there is not enough evidence to say, which hands the question back to clinical judgment.

#Fracture prevention: USPSTF 2018, all three rows

• Postmenopausal women: recommends against supplementation with 400 IU or less of vitamin D and 1,000 mg or less of calcium a day for the primary prevention of fractures in community-dwelling postmenopausal women — grade D.
• Men and premenopausal women: the current evidence is insufficient — grade I.
• Postmenopausal women, at higher doses: the current evidence is insufficient — grade I.

⚠️ Those three rows carry a scope limitation the task force writes for itself under "Patient Population Under Consideration", and it matters more than the grades themselves — what it excludes is four groups of people, not two: [Note 17]

1. those who have had an osteoporotic fracture;
2. those at increased risk of falls;
3. those with diagnosed osteoporosis;
4. those with diagnosed vitamin D deficiency.

If you are in any one of those four, the three rows above are not about you; whether and how much to take is decided by your doctor on your diagnosis. ⚠️ Items one and 2 are particularly easy to skip: someone who has fallen and broken a bone, or who has been assessed by a doctor as at high risk of falling, will very easily read that grade D as written for them — and the task force states in terms that it is not. In the "Response to Public Comment" section of the same page it records that this very misreading was the commonest concern at the time, and the page goes on to state that these people were excluded from the evidence review and are therefore excluded from this recommendation statement as well.

⚠️ The "Potential Harms" section of the same page turns the WHI kidney stone hazard ratio above into an absolute figure: [Note 17] over 7 years of follow-up, 1 in every 273 women given supplementation was diagnosed with a urinary tract stone — that is what "a hazard ratio of 1.17" looks like in people. And its last sentence is the same thing as Sanders 2010 above: 500,000 IU once a year, with an increase in falls and fractures. A trial's result and a task force's recommendation, matching each other on both sides.

#The one being updated: the draft is public, and its grades and dates are in print

⚠️ The 2018 recommendation page marks itself 「This topic is being updated.」 The link text on that 2018 page plus the sentence following it read together as 「Update in Progress for Vitamin D, Calcium, or Combined Supplementation for the Primary Prevention of Falls and Fractures in Community-Dwelling Adults: Preventive Medication」 (that sentence is printed on the old 2018 page and not on the update page itself), and the update page it links to self-dates as LAST UPDATED: Dec 17, 2024. Note the words "Falls and": the 2018 title speaks only of fractures, and the one being updated has added falls to it (that contrast is drawn by this article and is emphatically not in the original).

⚠️ And the draft recommendation statement that update page links on to is public, and carries draft grades in print. ⚠️ The sentence that the public comment period has closed is printed on the update page and not on the draft recommendation page: 「Public Comments are Closed for this topic.」 is on the update page, and that sentence does not appear on the draft recommendation page. This article attributes each sentence to the page it is actually printed on (both pages were re-read and checked separately on 9 August 2026). What follows is a draft and not final, and is not the current recommendation, but its differences from the 2018 three rows are large enough that they have to be given:

Both draft rows are written for the same population: community-dwelling postmenopausal women, and men aged 60 years or older — the second row applying that same age of 60 to falls as well as to fractures.

Two differences to remember. First, the 2018 grade D is tied to a dose — 400 IU or less of vitamin D a day with 1,000 mg or less of calcium; the draft's grade D has no dose ceiling. Second, 2018 gave men a grade I (insufficient evidence); the draft writes men aged 60 or over into grade D. The draft says for itself that once finalised it will replace the 2018 recommendation.

⚠️ The draft's exclusions are not quite the same as the 2018 one's, and the difference matters a great deal to some readers: the draft states that it does not apply to people who have had an osteoporotic fracture, who have a condition associated with vitamin D deficiency or malabsorption, or who have diagnosed osteoporosis or vitamin D deficiency. The 2018 one excludes those at increased risk of falls and the draft does not — the draft instead issues a grade D on falls directly. Someone taking vitamin D because of a risk of falls stands differently under the two documents, and that is something to raise with their doctor.

⚠️ The draft writes two sentences of its own in its "Definitions" section, and they decide how the two grade D ratings above should be read: what the draft argues against is taking it regardless of one's own diet, nutritional status or serum level; it does not say that vitamin D and calcium do not matter, and states on the same page that everyone should meet the recommended daily allowance — a figure that counts total intake including food and drink, not supplements alone. "You need not take a supplement" and "you need not meet the intake" are two different sentences.

The three rows of 2018 remain the current final recommendation. This article makes no statement about what the draft will eventually be finalised as.

#Vitamin C, zinc and the common cold

Vitamin C: the Hong Kong Department of Health has a sentence of its own in Chinese answering the question directly (the Drug Office's vitamins page, December 2024): it is popularly believed that vitamin C can prevent a cold or help a sufferer recover quickly, and that remains medically unestablished; while taking large amounts of vitamin C over a long period may increase the risk of kidney stones. [Note 18] (The character 「郤」 as printed in the original of that page is reproduced here as found.)

⚠️ Immediately after those three misconceptions the Department writes a sentence running the other way on the same page, which this article quotes with them because it bounds the three: apart from special circumstances such as illness or difficulty with absorption, a generally balanced diet already supplies us with enough vitamins. [Note 18]

Which is to say that not even the Department of Health writes "supplements never do anything". That sentence carries its own exception — the half-sentence about a balanced diet supplying enough vitamins cannot be read on its own, because the half that gets cut away is exactly the exception: illness, and difficulty with absorption. With the other sentence, that page lists five classes of exception in all, spread across two sentences: illness, difficulty with absorption, pregnancy, breastfeeding and smoking. That runs in the same direction as the exclusions in the USPSTF document below.

The same page has one more passage that is a direct instruction to stop, about vitamin B6: peripheral neuropathy is a possible adverse effect of vitamin B6, and where it occurs the supplement should be stopped and advice sought from a healthcare professional as soon as possible. [Note 18]

Who this passage is most use to: anyone taking a multivitamin or a B complex who is starting to get tingling, burning or numbness in the hands or feet. The sentence above is the Department of Health's own Chinese, and so is the action: stop, then find a healthcare professional as soon as possible. The USPSTF passage below also mentions that a high intake of vitamin B6 (35 mg a day or more) is associated with an increased risk of hip fracture; those are two different sources and two different outcomes, and are not to be run together.

Zinc: a Cochrane review of 2024 (Nault et al, 34 studies and 8,526 participants) assessed zinc for preventing and treating the common cold. This article does not quote that review's text (the reason is under "What this article does not state" at the end) and only reports it by attribution: the authors rated the certainty for prevention as low; they rated the certainty for shortening the illness as low as well, with extremely high heterogeneity between the trials in that pooled result (I²=97%); and they assessed zinc used as treatment as increasing the risk of non-serious adverse events (moderate certainty). Any account presenting that review as "zinc shortens a cold by about 2.4 days" without giving the certainty rating and the heterogeneity is a misstatement.

Who this section is most use to: anyone who buys vitamin C and zinc as soon as autumn comes. The two passages above describe the state of the current evidence, not an instruction. If you already have a history of kidney stones, the Department of Health's sentence about large amounts of vitamin C taken long term and kidney stones is the one written for you.

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#How much counts as too much? The tolerable upper intake level, and why "no upper limit" is not a safety statement

The biggest difference between a supplement and food is that you can swallow, in a second, an amount far beyond anything a diet could reach. The Tolerable Upper Intake Level (UL) is the figure that exists for exactly that.

The same overview also states that the UL is not a line with trouble on one side and safety on the other: the Food and Nutrition Board acknowledges that the manifestations of vitamin D toxicity usually appear at much higher levels, but it also writes down something else — that serum 25-hydroxyvitamin D levels of about 75–120 nmol/L are already associated with several classes of bad outcome. [Note 19] ⚠️ That second sentence is the substance of the statement that the UL is not a safety line. It is a blood measure and not a dose, and cannot be converted directly into how many IU a day to take.

On the consequences of too much vitamin D, the same overview says: it can cause hypercalcaemia, hypercalciuria and kidney stones. ⚠️ That last item points straight at the WHI kidney stone result above. Note that the words the source uses are "may increase the risk" — that is, taking calcium and vitamin D together may increase the risk of certain adverse effects, the source not saying that the combination necessarily does. [Note 19]

⚠️ But immediately after dealing with WHI, the same overview bounds the weight of that conclusion in the very next sentence: [Note 19] two things to remember. First, the source states for itself that WHI's 17% arose against a background of about 2,100 mg of calcium a day in total intake including food — not from that 1,000 mg supplement alone. Second, kidney stones were not seen in every trial: what the other, shorter trials saw was hypercalcaemia and hypercalciuria, not stones. That does not cancel the WHI result, but it bounds the flat statement that calcium plus vitamin D equals kidney stones.

The Hong Kong Department of Health's own Chinese on the same subject (the Drug Office's vitamins page, December 2024) is: many parents believe that taking more vitamins will give children an appetite, make them taller, more alert and cleverer, and in fact none of that has any scientific basis. [Note 20]

The same overview also states what that UL is set for and how much data it rests on. [Note 21] ⚠️ Two things to remember. First, this UL is set on the risk of bleeding — not on prostate cancer and not on mortality, so from beginning to end it cannot answer the question SELECT and Miller were asking. Second, the table above begins at "1–3 years" not because infants are without risk but because the board never set that line for infants, as that page says itself.

Do the arithmetic once (below the upper limit is not the same as the trial result being safe): vitamin E product labels in Hong Kong sometimes use milligrams and sometimes IU. The ODS overview gives the conversion: 「1 IU of the natural form is equivalent to 0.67 mg of alpha-tocopherol. 1 IU of the synthetic form is equivalent to 0.45 mg of alpha-tocopherol.」 The SELECT trial used 400 IU a day. Converting: natural form, 400 × 0.67 = 268 mg; synthetic form, 400 × 0.45 = 180 mg. The UL for adults (19 and over) is 1,000 mg. 268 ÷ 1,000 = 26.8% (natural form); 180 ÷ 1,000 = 18.0% (synthetic). ⚠️ The evidence file records only that SELECT used a dose of 400 IU, and not whether the vitamin E was the natural or the synthetic form, so no single percentage can be given here. That is to say, the dose SELECT used was between 18.0% and 26.8% of the upper limit (a fifth to a little over a quarter, depending on the form), and that trial's 2011 report still recorded an increase in the risk of prostate cancer (hazard ratio 1.17, 99% CI 1.004-1.36). In one sentence: the UL is a line drawn in toxicology, not a certificate that a trial has shown it safe. A dose below the UL can still produce a bad result in a trial. And more than one source says so: the dose-response analysis of Miller et al (above) puts the rise in risk above 150 IU a day — which converts to about 100 mg of the natural form and about 68 mg of the synthetic, roughly 10% of the adult UL of 1,000 mg.

⚠️ That table carries a note that bears directly on anyone reading a multivitamin label: this UL governs preformed vitamin A (retinol or its esters) only, and does not govern the part that comes from beta-carotene. [Note 21] Those last two sentences are the part that is really of use to someone standing in a pharmacy with a multivitamin in hand. That example also answers something in passing: the same amount that is below the UL for an adult is already above the UL for a child under eight.

#Beta-carotene has no UL — and "no upper limit" is not a safety statement

The same overview first says how beta-carotene differs from preformed vitamin A, which bounds the sentence that follows: beta-carotene has no known teratogenicity or reproductive toxicity as yet, and the commonest consequence of too much is a reversible discoloration of the skin; the board set no UL for it, but at the same time advises the general population against its supplement form, entirely on the strength of the two trials above. [Note 22]

Which is to say: beta-carotene's problem is not toxicity but the trial results. "No known" is "not known", not "shown to be absent", and this article does not treat the two as the same thing. The same body set no upper limit for beta-carotene on the one hand, and on the other advises the general population directly against its supplement form. No UL does not mean safe; it means only that no numerical line has been drawn.

⚠️ Conversely, "no UL" is not necessarily bad news either — the same board says something quite different about vitamin K, and writes down its reason: no UL was set for vitamin K because of its low potential for toxicity. [Note 22] In one sentence: there are two kinds of "no upper limit", and which one it is depends on the reason the source gives. Beta-carotene has no line drawn but has adverse trial results; vitamin K has no line drawn because of low toxic potential, and the board says so in terms. The two must not be treated as the same thing. As for vitamin K, its real problem is not the dose but the warfarin interaction in the next section.

#USPSTF's own section on harms

⚠️ A statement of completeness: what follows are the harms USPSTF identified for the supplements it reviewed, complete as printed; the task force does not present it as an exhaustive list of supplement harms. That section runs to two paragraphs, and both are reproduced in the notes. [Note 23] The first says that for many of the vitamins and nutrients reviewed there was little evidence of serious harm; but that in people who smoke tobacco or who have had occupational exposure to asbestos, one important harm of beta-carotene use was reported — an increased incidence of lung cancer.

⚠️ The second paragraph has a dose gradient in it, which must not be read past: vitamin A supplements are associated with reduced bone density already at moderate doses, and it is at high doses that hepatotoxicity and teratogenicity are mentioned — that is, "not yet at a toxic dose" does not mean being on the safe side. Not being on this list does not mean safe — and the task force itself uses two different lists in two places on the same page.

Who this section is most use to: anyone taking several products at once. The ULs in the tables above are limits on total intake, not counted once per bottle — but how "total intake" is counted differs between vitamins, and one formula cannot be copied across. The vitamin E UL governs all supplemental alpha-tocopherol added together: a multivitamin plus a single-vitamin capsule plus a fortified drink, and the vitamin E figures are simply added. ⚠️ Vitamin A is different: its UL governs preformed vitamin A only, so if some or all of the vitamin A on the label comes from beta-carotene, the label's vitamin A figures cannot simply be added — the note above has to be followed, picking out the percentage that is retinol or retinyl ester first.

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#Will a supplement collide with the drugs you are already taking?

This is the section most likely to affect a person directly, so one thing has to be said plainly: not one of the six lists below is a complete list. All six sources use words of their own marking them as examples.

Before reading this section:

• Every list is introduced by the source's own language of example — 「A few examples are provided below.」 / 「Some examples are provided below.」 / 「For example,」.
• This article has added nothing to any of the lists. What is on a list is what is on it.
• "The drug I take is not on the list" ≠ "there will be no interaction". That inference does not hold, and every source in this section says so.
• ⚠️ In the four NIH ODS tables below, the bold drug name and the "—" in the left column are this article's typesetting and not what the original prints (the original has a subheading followed by a separate paragraph), and the reference numbers inside the original paragraphs have been omitted.

#Red yeast rice — sold in Hong Kong as a health product, and pharmacologically a statin

This is the item that should come first in this section, because the Hong Kong Department of Health wrote it down itself in Chinese (the Drug Office's page on interactions between drugs and food and drink, February 2020). ⚠️ First, what it is, because that page opens by separating two things that are easily confused: red yeast rice is not the same as red rice, and the Department states that red yeast rice must not be eaten as a staple food. [Note 24]

And modern medicine has found that the substance monacolin K in red yeast rice helps lower blood cholesterol — the lactone form of monacolin K is chemically identical to the drug called lovastatin, and common foods or health products containing red yeast rice may contain variable amounts of lovastatin. [Note 24]

In one sentence: a thing sold as a food or a health product is pharmacologically the same substance as a prescription drug, in a variable amount. That is published by the Hong Kong government itself, in Chinese, and anyone can look it up. And the action is the Department's own: anyone taking red yeast rice should tell their doctor.

The same page has a passage that anyone taking calcium should read, and it runs in both directions: on one side calcium reduces the effect of drugs (tetracycline, ciprofloxacin, levofloxacin and other antibiotics, and bisphosphonates — to be separated by at least 30 minutes); on the other, certain drugs raise the level of calcium in the body (antacids, thiazide diuretics, lithium, thyroxine), and the Department writes the consequence plainly — in severe cases, convulsions and coma. [Note 25] That is the same thing as the NIH ODS row below on thiazide diuretics with vitamin D causing hypercalcaemia, said once each by two bodies in two languages. For someone taking a thiazide diuretic, a calcium tablet and vitamin D at the same time, all three point the same way.

⚠️ That page states for itself that it gives examples: 「可能與藥物產生相互作用的食物／飲料種類繁多，下文為其中一些例子。」 — there are many kinds of food and drink that may interact with drugs, and the following are some examples. The seven it lists in all are: alcohol, foods containing caffeine, foods containing calcium, fruit juices (grapefruit juice, apple juice and orange juice), red yeast rice, foods containing potassium, and foods containing tyramine.

#Vitamin D × drugs (NIH ODS, updated 27 June 2025)

Completeness status: expressly examples. The section opens by saying for itself that vitamin D supplements may interact with several types of medication, that a few examples are provided below, and that people taking these and other medications regularly should discuss their vitamin D intakes and status with their health care providers.

(In substance: orlistat together with a reduced-fat diet lowers 25(OH)D levels; statins reduce cholesterol synthesis and so may reduce vitamin D synthesis, while high intakes of vitamin D may reduce the potency of atorvastatin, lovastatin and simvastatin; corticosteroids reduce calcium absorption and impair vitamin D metabolism, with 25(OH)D deficiency below 25 nmol/L [10 ng/mL] more than twice as common among reported oral steroid users (11%) as among non-users (5%) in NHANES 2001–2006; and thiazide diuretics taken with vitamin D supplements may lead to hypercalcaemia.)

#Vitamin K × warfarin (NIH ODS, updated 29 March 2021)

Completeness status: expressly examples.

⚠️ Note the direction of the source's instruction: it is "keep it consistent", not "eat less of it". Another passage in the same overview states that people taking these anticoagulants need to maintain a consistent intake of vitamin K. This article has not told anyone, and will not tell anyone, to cut down on dark green vegetables — the source does not say that. If you are on warfarin and want to change your diet or add a supplement, that is something to take to your doctor or pharmacist.

#Vitamin E × drugs (NIH ODS, updated 26 March 2021)

Completeness status: expressly examples.

(In substance: vitamin E can inhibit platelet aggregation and antagonise vitamin K-dependent clotting factors, so large doses with an anticoagulant or antiplatelet drug can increase the risk of bleeding, the amount needed for a clinically significant effect being unknown but probably above 400 IU a day; a collection of antioxidant ingredients blunted the rise in HDL cholesterol, and especially in HDL2, among people treated with simvastatin and niacin; and oncologists generally advise against antioxidant supplements during chemotherapy or radiotherapy.)

#Vitamin A × drugs (NIH ODS, updated 10 March 2025)

Completeness status: expressly examples.

#St John's wort — nine classes of drug, on a list that says for itself it is examples

The United States National Center for Complementary and Integrative Health (NCCIH, updated May 2025) has a summarising sentence on this one: St John's wort has been clearly shown to interact with many medicines. And the sentence before the list is a general instruction: if you take any kind of medication, talk with your health care provider before using St John's wort or any other herbal product, because some herbs and medicines interact in harmful ways. Completeness status: expressly examples — the drug list is introduced by 「For example,」. The complete list of the nine classes, and NCCIH's own "Keep in Mind" section immediately following, are reproduced in the notes. [Note 26]

⚠️ The same page also says why people take it, and this article quotes that too, because giving only the risk and not this half is not what that page says: for most adults who are not taking any medication, St John's wort appears to be more effective than placebo for mild to moderate depression. [Note 26]

Who this section is most use to: anyone taking the contraceptive pill, an anticoagulant, an antiepileptic, an anti-rejection drug after an organ transplant, an HIV drug or a cancer drug. On this list, the direction of St John's wort's effect is to weaken those drugs — a "herbal, natural" thing making your prescription drug less effective. And the list says for itself that it is examples. And if you are taking it for your mood, NCCIH's own sentence is the one that applies: depression can be serious, so see a health care provider.

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#Does more protein powder make you bigger? The Consumer Council answered that itself in April 2026

The main source for this section is local, free and originally in Chinese: issue 594 of the Consumer Council's CHOICE magazine (April 2026), 〈蛋白粉人人合適？坊間迷思逐一拆解〉, on whether protein powder suits everyone. On sports supplements in Hong Kong there is no need to detour through America.

Protein powder is a concentrated form of food, generally made from milk, beans and other protein-rich foods by extraction, filtration and drying. ⚠️ The sentence immediately after the one on composition is particularly telling in an article like this: among the added ingredients the Consumer Council lists are caffeine, creatine and beta-alanine — that is, the three things each of which has a section of its own later in this article. A tub of protein powder can also be a tub of caffeine product, and you will only see it on the ingredient list. [Note 27]

How much protein is needed? The Consumer Council lists four reference values in the same issue, all of them reproduced in the notes. [Note 27] On "will eating more make me bigger?", the Consumer Council's answer is one sentence in Chinese: even where an ordinary person takes in more than the basic requirement, it will not make the muscle "grow faster"; the benefit of additional protein diminishes progressively, and surplus protein cannot be stored by the body but only broken down and excreted. [Note 27]

The international figures point the same way. Morton et al (Br J Sports Med 2018) pooled 49 studies and 1,863 participants in randomised resistance training trials: beyond a total protein intake of 1.62 g per kilogram of body weight a day, supplementary protein produced no additional gain in fat-free mass. [Note 28] The direction of the two modifiers is worth remembering: the older the person, the smaller the effect of supplementary protein on fat-free mass; and the effect is larger in people who already have a resistance training habit. Both point at the same conclusion — the powder is not a substitute, and the exercise is the condition.

The same abstract also lists the effects supplementary protein does have (the other side of the mirror): 2.49 kg more on a one-repetition maximum and 0.30 kg more fat-free mass. [Note 28] In one sentence: the effect is real, but small, and it has a ceiling. That is the average effect after pooling 49 studies, not the effect in the advertisements.

Do the arithmetic once (a 70 kg person with a regular training habit): On the Consumer Council's reference value for active people of 1.4–2.0 g/kg: 70 × 1.4 = 98 g; 70 × 2.0 = 140 g of protein a day. On Morton's ceiling of 1.62 g/kg: 70 × 1.62 = 113.4 g a day. On the Consumer Council's own table of high-protein foods (per 100 g): chicken breast is about 31 g of protein. 113.4 ÷ 31 = 3.66, so about 366 g of chicken breast reaches that ceiling. From the same table: tuna about 26 g, firm tofu about 15 g, a whole egg about 13 g, Greek yoghurt (unsweetened, low fat) about 10 g, and whole milk about 3.4 g (all per 100 g). The point of that sum is not to tell you not to drink protein powder; it is to tell you to do the sum yourself and see how far your ordinary diet is from that figure. Far from it and just short of it are two different situations.

#Plant protein is not the same as animal protein — the Consumer Council puts it in DIAAS

The Consumer Council also warns that consumers should not make protein powder their only source of protein, and should keep to a balanced diet and take protein from a variety of foods. [Note 29]

#Older people, sarcopenia, and "protein alone does nothing"

Muscle mass begins to change from about the age of 30 and accelerates after 60, and by 80 as much as 30% to 40% of muscle mass may have been lost. [Note 30]

Who this passage is most use to: anyone buying protein powder for an older family member without arranging any resistance exercise alongside it. The Consumer Council's own Chinese is that without exercise, adding protein alone has very limited effect. But the same page also sets down what protein powder is really for in an older person — those whose appetite, chewing or digestion has declined and who cannot get enough protein from ordinary meals, for whom the powder is easy to swallow and easy to absorb. Only the two sentences together are the complete answer: the powder solves "cannot eat it", and does not solve "has not moved". And Morton et al's meta-analysis also shows that the effect of supplementary protein on fat-free mass falls with age — which makes arranging resistance training alongside it more important, not less.

#High protein and kidney function

Devries et al (J Nutr 2018) pooled 28 trials and 1,358 participants, high protein being defined as 1.5 g or more per kilogram of body weight, or 20% or more of energy, or 100 g or more of protein a day, in adults without kidney disease. ⚠️ There is a lower time bound in the inclusion criteria, and it is low enough that it has to be stated: what was included were randomised controlled trials lasting more than 4 days. That is to say, those 28 trials may include trials that ran only a few days — and a reader asking whether taking protein powder long term harms the kidneys is not asking about a few days. That abstract does not print the actual distribution of trial durations, and this article will not estimate it. [Note 31]

⚠️ This article reports an internal tension and does not adjudicate it. The two results in the same abstract run in different directions: the post-intervention between-group comparison is significant (the original: 「standardized mean difference (SMD): 0.19; 95% CI: 0.07, 0.31; P = 0.002」), while the comparison of change is not (SMD 0.11, 95% CI −0.05–0.27, P=0.16). The authors incline to read this as no adverse effect; a strict reader could read the first result the other way. The authors also state their own limitation: the main limitation of this analysis is the unclear risk of selection bias in the included trials.

⚠️ The scope word is "healthy". That analysis expressly excluded people with kidney disease, so it says nothing at all about anyone who already has it. And no source in this article supports the statement that in stage 3 or worse chronic kidney disease excess protein accelerates the decline in kidney function, so this article does not write it. In that situation the Consumer Council's own sentence is the most direct: people with a chronic disease (chronic kidney disease, for instance) or with other special medical needs should seek an individual assessment from a registered dietitian and other healthcare professionals. [Note 31]

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#How large is creatine's effect, and how safe is it?

Creatine is the sports supplement covered in this article with the clearest effect figures — and also the one whose safety evidence most needs its funding relationships stated. This article does both.

The effect figures, dosing regimens and safety statements of the International Society of Sports Nutrition (ISSN)'s position stand of 2017 are reproduced in full in the notes. [Note 32] On effect, that statement reports a performance improvement of 10% to 20%. As for the popular claims that creatine causes dehydration, cramping and kidney damage, that document's own words are that there is no evidence that it does.

⚠️ Note that this article does not write "creatine does not cause dehydration" or "does not cause acute kidney injury". What the source writes is 「no evidence that」 — that is, no evidence has shown it. "No evidence has shown it" and "it does not" are two different sentences, and this article writes back the one the source wrote. ⚠️ Equally, the last sentence of that document is about a lower incidence of injuries, not of cramping. The two words are not interchangeable.

One primary study independent of the ISSN (Poortmans and Francaux, Med Sci Sports Exerc 1999, comparing people who had taken creatine for 10 months to 5 years against controls; ⚠️ that abstract does not give a sample size, and this article will not estimate it) confines its conclusion to the kidneys of healthy people. ⚠️ That abstract also records a comment published on that paper (Comment in Med Sci Sports Exerc. 2000;32(1):248-9). This article has not read that comment and so makes no statement about what it says; it discloses its existence because that paper is the only independent corroboration this article cites.

#The most useful thing to know about creatine: it raises the creatinine on your blood report

Antonio et al (J Int Soc Sports Nutr 2021) state that creatine and phosphocreatine in skeletal muscle degrade non-enzymatically into creatinine, so that taking creatine raises blood creatinine; and that clinicians should be cautious in interpreting creatinine and estimating kidney function in people taking creatine or with a high meat intake. [Note 33]

⚠️ Note who the source's instruction is addressed to. That second sentence is about clinicians and is not an instruction to the reader. No source consulted for this article recommends stopping creatine for a week or for any period before a blood test, so this article does not write that. What can practically be done is: tell the healthcare staff you take creatine when you have blood taken — because on the source above, they need to know it when they interpret that number.

#Product purity — a passage bearing directly on the Hong Kong market

The same paper states that creatine monohydrate products from other sources may contain impurities or undeclared ingredients. [Note 34]

Who this section is most use to: anyone in doubt about whether creatine works. The effect figures above are the strongest set among the supplements covered in this article; and the funding relationships behind the safety evidence are the subject of the next section.

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#Who paid for this evidence?

This section is not an accusation but a fact about where the evidence comes from. A reader opening a paper's abstract cannot see the declarations of interest underneath; and on the subject of supplements those declarations are dense enough that they have to be given. The funding and interest statements of four documents are reproduced word for word in the notes. [Note 35]

One: the safety argument for creatine comes from a document funded by, and written at the request of, an American supplement industry body (this article has not obtained that body's own constitution page, and so reports only the name as it appears in the paper's declaration of interest). And the only independent corroboration this article cites is the study of Poortmans and Francaux from 1999 — an abstract with no sample size, whose own conclusion goes no further than the kidneys of healthy people, and on which a comment this article has not read was published. That is the state of the evidence: the effect figures are clear; the body of the safety argument comes from an industry-funded document; and the only independent corroboration is small, old, without a sample size, and bounded in scope. This article states it and does not adjudicate.

Two: the finding that protein works and the finding that it is safe for the kidneys come from the same research group, and that group declared dairy industry funding. Morton et al (the benefit) and Devries et al (the kidney safety) both come from authors at McMaster University as recorded in the papers' declarations of interest. That paper also carries a correction of 2020, whose content is only the addition of one declaration of interest, with no data altered.

Three: the caffeine position stand also carries declarations.

Those declarations do not invalidate the findings — a study with a declaration of interest is not a wrong study. But they change one thing: when the principal evidence for "safe" has a funding relationship with the seller, and the independent corroboration is thin, a reader ought to know where they are standing. That is why this article lists them.

Who this section is most use to: anyone who sees the claim that "research proves it is safe". The next question to ask is not whether there is research, but who paid for it, and whether anyone independent has done the same thing.

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#Caffeine, beta-alanine, precursors and SARMs: which have an effect, and which have been named by regulators?

#Caffeine — the ISSN's eleven positions

⚠️ Note one thing first: the ISSN's eleven positions are about doses for athletic performance and not about a safety ceiling — not one of the eleven sets a daily upper limit. The safety ceiling is another matter and does have official figures, and the two are not to be run together. All eleven are reproduced in full in the notes. [Note 37]

The European Food Safety Authority (EFSA) states on its caffeine topic page (consulted 3 August 2026): intakes of up to 400 mg a day, spread across the day, raise no safety concern for healthy adults. [Note 36] ⚠️ That sentence carries three conditions and none may be dropped. First, it is about "healthy adults"; second, it must be spread across the day and not taken at once; third, it expressly excludes pregnant women — whose figure is 200 mg a day.

⚠️ And there is one more, the first item on the "adults" list, and it is the one most relevant to this section — because what it describes is exactly the pre-exercise dose: single doses of up to 200 mg (about 3 mg per kilogram of body weight), including when taken within two hours of intense physical exercise, raise no safety concern for healthy adults. [Note 36]

⚠️ That sentence has to be read with the ISSN's eleven, because the two sets of figures collide. The ISSN's performance dose is 3 to 6 mg per kilogram of body weight; EFSA's single dose of no concern is about 3 mg per kilogram, capped at 200 mg. For a 70 kg person the ISSN range is 210 to 420 mg in one dose, and the upper half of it already exceeds EFSA's single-dose figure. The two do not conflict — one is about performance and the other about safety — but neither can be used alone to decide how much to take. And for pregnant women and for middle-aged and older people doing intense exercise, EFSA states in terms that there are no studies: that is "unknown", not "safe".

⚠️ And one thing governs all the figures above: EFSA sets out on the same page which situations it did not assess, and the second of them is "together with medication". [Note 36] That is to say: the 400 mg and 200 mg above are about people with no disease and on no drugs. If you have a long-term condition or are taking medication, those figures were never calculated for your situation — EFSA says so itself.

Which is to say: the widely quoted "400 mg a day" does have a source, and the source is EFSA. But lifting the number out without the three conditions is no longer saying what EFSA said — the figure for pregnant women is 200 mg, not 400; and if what you mean is the dose swallowed at once before exercise, EFSA's figure is 200 mg, not 400.

#Hong Kong's own figures: the Centre for Food Safety

All of the above is EFSA. The Hong Kong Centre for Food Safety has a set of its own, written in Chinese, and it differs from EFSA in two places — both of them falling on the two groups where accuracy matters most. The Centre for Food Safety and Consumer Council's 2013 study page on the caffeine content of coffee and tea prepared in local eateries states: for generally healthy adults, provided a balanced diet is kept, the caffeine taken in from a moderate amount of coffee and tea should not produce adverse effects; and pregnant and breastfeeding women should limit caffeine intake to no more than 200–300 mg a day. The same centre's page on coffee as an everyday breakfast drink also records the other side, of stopping: habitual coffee drinkers who suddenly stop will get withdrawal symptoms such as headache, fatigue, irritability and difficulty concentrating. [Note 38]

On the pregnancy row, one of the two figures is the wider and the other the stricter. This article lists both and does not adjudicate; and if you have to pick one, the stricter is EFSA's 200 mg. The same on the children's row: the upper end of the Centre for Food Safety's range (5 mg/kg) is above EFSA's (3 mg/kg) and its lower end (2.5 mg/kg) is below.

Who this passage is most use to: anyone pregnant or planning a pregnancy who drinks coffee or tea every day. On how much caffeine is in a cup, the Centre for Food Safety has two figures on two different pages, and this article gives both rather than letting one stand in for the other.

• Food Safety Focus issue one hundred and fifty-three (April 2019) gives a reference figure: a cup of coffee may contain about 90 to 200 mg of caffeine, depending on how it is made.
• And the joint study of 2013 above bought 80 samples in Hong Kong eateries and analysed them, and the per-cup figures it measured are higher than that range: ordinary coffee averaged 200 mg a cup with a range of 110 to 380 mg; Hong Kong style milk tea averaged 170 mg a cup with a range of 73 to 220 mg; and Taiwanese style milk tea averaged 130 mg with a range of 100 to 160 mg.

That difference matters a great deal in pregnancy. On the reference range (90 to 200 mg a cup), a single cup can already reach 200 mg — that is, one cup alone touches EFSA's line and reaches the lower end of the Hong Kong 200 to 300 mg line, without waiting for a second; and on the figures actually measured in Hong Kong eateries, a single cup of ordinary coffee can already reach 380 mg, far beyond either body's line. Both figures are published by the Centre for Food Safety itself and this article does not adjudicate; but if you are going to use one to work out how much you drink, the measured one is the reality of a Hong Kong eatery.

#Beta-alanine — the ISSN's seven conclusions

All seven conclusions are reproduced in full in the notes. [Note 39] ⚠️ Conclusion 7 is insufficient evidence, not "shown to have no effect". Those two are not interchangeable.

#"Natural" anabolics and steroid precursors — three randomised trials, three zeros

The word-for-word originals of the three trials are reproduced in the notes. [Note 40] ⚠️ On the androstenedione one, note first what that product was actually doing: serum oestradiol rose.

#SARMs and "bodybuilding products" — the United States Food and Drug Administration's warnings

⚠️ Completeness status: both lists below are introduced by "such as" or "particularly" and are expressly examples, not exhaustive. [Note 41]

The harms the United States Food and Drug Administration (FDA) lists for SARMs in its consumer update (the page self-dated 04/26/2023) rest on what the FDA itself calls research and reports, and not only on adverse event reporting; and the FDA separately continues to receive adverse event reports involving SARMs, stating for itself that they are under-reported, so that the number of consumers actually experiencing adverse events is likely higher than the number reported. The FDA also states that these products often carry no warning at all on the label, so "there is no warning on the packaging" is not a safety signal.

The same body's consumer update on bodybuilding products (the page self-dated 09/20/2024) has a section headed "What to Do", and the first sentence governing the whole section runs contrary to the instinct to stop at once — it advises consulting a health care professional first, because of dangerous withdrawal problems. ⚠️ That has to be kept apart from the two slimming product cases in section 2 of this article: the two sources give instructions running in opposite directions, and each governs only its own class of product. Working out which class the thing in your hand belongs to is the precondition for reading these two sentences.

The two cannot be moved across to each other. ⚠️ The language status has to be stated too: the Department of Health sentence is a Chinese original reproduced word for word; the FDA sentence is an English original. If you are not sure which class the thing in your hand belongs to, treat it as the second — because the second instruction (find someone first) cannot go wrong in either situation.

⚠️ Both documents above describe the American system. One of them, "Caution: Bodybuilding Products Can Be Risky", states that the FDA does not review dietary supplements for safety and effectiveness before they go on the market, so that products illegally marketed as dietary supplements are generally only found after they have already reached the market — that sentence is about the United States and cannot be moved onto Hong Kong, whose framework is the one in the first section of this article.

⚠️ Which class testosterone falls into in Hong Kong can be answered from the Drug Office's database. Searching the Search Drug Database of registered pharmaceutical products by the active ingredient testosterone (consulted 3 August 2026, the database self-reporting Last Updated: 31-Jul-2026) returns 6 registered pharmaceutical products, each of whose detail pages prints its legal classification and sale requirement. Taking one of them as an example:

Which is to say: in Hong Kong a registered pharmaceutical product containing testosterone is a prescription drug, and the classification is made by the Pharmacy and Poisons Board of Hong Kong under the Pharmacy and Poisons Ordinance (Chapter 138), not by the Hospital Authority. ⚠️ That is a statement about registered products. What is inside an unregistered "bodybuilding product" that declares nothing on its label is outside the scope of that database.

#Undeclared ingredients — an old international figure, and a new Hong Kong list

There is one much-quoted figure: Geyer et al (Int J Sports Med 2004) bought 634 non-hormonal supplements from 215 suppliers in 13 countries, and 94 of the 634 samples (14.8%) were found to contain anabolic androgenic steroids not declared on the label. [Note 42]

⚠️ Those products were bought between October 2000 and November 2001. That is a snapshot of an international market twenty-five years ago, and cannot be treated as today's figure, still less as a Hong Kong figure.

⚠️ Which 13 countries those 13 purchasing places were is not listed in that abstract. It says only two things: that as a proportion of the total bought in each place, the highest proportions of positive products were the Netherlands (25.8%), Austria (22.7%), the United Kingdom (18.8%) and the United States (18.8%); and that by the labels, all the positive supplements came from companies in only five countries — the United States, the Netherlands, the United Kingdom, Italy and Germany. Those two lists answer two different questions — one is about where they were bought and the other about where the companies are registered. This article therefore makes no statement about whether Hong Kong was among the 13 purchasing places.

⚠️ Two figures a reader can use better: among supplements from companies that also sold steroid precursors, the positive proportion was 21.1%; among those from companies that did not, it was 9.6%. That is to say, in that market of that era, which company you bought from predicted the contamination risk better than what you bought — by more than a factor of two.

So the 14.8% is a lower bound rather than a complete proportion — 66 of the samples in the denominator could not be analysed at all. [Note 42] The same group's follow-up report of 2008 records more deliberate adulteration: 「Since 2002, also products intentionally faked with high amounts of 'classic' anabolic steroids such as metandienone, stanozolol, boldenone, dehydrochloromethyl-testosterone, oxandrolone etc. have been detected on the nutritional supplement market. These anabolic steroids were not declared on the labels either.」

For the Hong Kong market, the Department of Health list in section 2 of this article is the right tool — it is local, current, dated, and you can search it yourself.

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#What to do next

Not one recommendation in this article is about what to take. This section sets out three checks, all three supported by the Hong Kong government's own pages and all three within your own power to do.

1. Check one: look for an HK-XXXXX registration number on the label, and for what else the label should carry. That number identifies a pharmaceutical product; a product making a claim to treat or prevent disease without one is a signal worth pausing on. The Department of Health press release puts it more directly: the safety, quality and efficacy of unregistered pharmaceutical products are not guaranteed. And besides the registration number there are eight further particulars a label must carry, all reproduced in the notes. [Note 43] In one sentence: an HK number printed on its own is not enough. Packaging with no ingredient amounts, no batch number, no expiry date and no manufacturer's address does not match that list.
2. Check two: search for the product in the Drug Office's list of slimming products with undeclared Western drug ingredients. The address of the list is in the second section of this article and at the end; both language versions are searchable.
3. Check three: verify the HK-XXXXX number directly against the registration database. Check one is about whether there is a number on the label; this step is about whether there is anything behind that number. The Search Drug Database has a "Hong Kong Registration Number" field under its advanced search, and can also be searched by product or pharmaceutical name or by certificate holder. ⚠️ Note that the search results pages are available in English only (as that page states itself), and that a registration record does not carry indications — that is, the database can prove that a product is registered and cannot prove what it does. The "Sale Requirement" field is the most useful of all to an ordinary person — it states directly whether the product is Prescription only Medicines, Pharmacy only Medicines or Over-The-Counter Medicines.

⚠️ One check that does not exist has to be said plainly: there is no such procedure as verifying whether a product has been tested by the Hong Kong Department of Health. The Department does not issue "tested" certification for supplements. The three above are the checks that actually exist.

Who this section is most use to: anyone about to buy slimming, figure-shaping or bodybuilding products online or through a buying agent. In the two cases in the second section of this article, both times it was the Department of Health that bought the problem product through an online channel — once on a social media platform and once on an instant messaging app.

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#Frequently asked questions

So do supplements all do nothing?

No, and the generalisation is itself wrong. The USPSTF document of 2022 expressly excludes children, people who are pregnant or may become pregnant, people with chronic disease, hospital inpatients and people with known nutritional deficiency; and it separately recommends that people planning a pregnancy or capable of pregnancy take a supplement containing 0.4 to 0.8 mg of folic acid a day. What the trials examined was healthy adults using supplements to prevent cardiovascular disease and cancer, and the answer was grade D and grade I — not "supplements all do nothing".

VITAL used 2,000 IU of vitamin D a day, but Hong Kong says more than 1,000 IU needs a prescription — is the bottle I bought illegal?

Those are two different legal categories, and this article will not and cannot draw a conclusion about any individual product. The Department of Health's threshold governs the class of "pharmaceutical products" — whether a product is one has to be judged on the definition in Chapter 138 of the Pharmacy and Poisons Ordinance (see the first section of this article); and VITAL's 2,000 IU is the dose in an American trial, not a Hong Kong legal classification. If in doubt, ask a pharmacist or a doctor.

Is fish oil good for the heart?

The result of the VITAL trial (25,871 people, median follow-up 5.3 years) was: major cardiovascular events in 386 people in the n-3 arm against 419 on placebo, a hazard ratio of 0.92 (95% CI 0.80–1.06); and the authors conclude that supplementation did not lower the incidence of major cardiovascular events or of cancer compared with placebo. In the same abstract the secondary endpoint of total myocardial infarction has a hazard ratio of 0.72 (0.59–0.90) — a secondary endpoint inside a trial whose primary endpoints were both zero, and one of six secondary endpoints in the same sentence. Both sides are set out above.

Is red yeast rice safer than a statin?

The Department of Health states in its own Chinese that the lactone form of monacolin K in red yeast rice 「於化學上與名為『洛伐他汀』的藥物完全相同」, is chemically identical to the drug called lovastatin, and that common foods and health products containing red yeast rice 「都可能包含不定份量的『洛伐他汀』」, may all contain variable amounts of lovastatin. The same page also states that statins are prescription drugs under Chapter 138, and tells anyone taking red yeast rice to tell their doctor.

Does protein powder harm the kidneys?

For adults without kidney disease, the conclusion of Devries et al (2018, 28 trials and 1,358 people) is that a high protein intake had no adverse effect on kidney function as measured by glomerular filtration rate; but the two results in the same abstract run in different directions, and the authors themselves state that the risk of selection bias is unclear. ⚠️ And there is a lower time bound: the inclusion criteria of that analysis required only that a trial last "more than 4 days", and the abstract does not print the actual durations — so it cannot answer the question about taking it long term. That analysis excluded people with kidney disease, so it says nothing at all about anyone who already has it. The Consumer Council (April 2026) on that group says: people with a chronic disease (chronic kidney disease, for instance) or with other special medical needs should seek an individual assessment from a registered dietitian and other healthcare professionals.

Will eating more protein make me bigger?

The Consumer Council (April 2026): 「一般人即使攝入超過基本所需分量，也不會讓肌肉「長得更快」，額外的蛋白質營養所帶來的效果會逐漸遞減，多餘的蛋白質不能被身體儲存，只能被分解和排出體外。」 — even where an ordinary person takes in more than the basic requirement it will not make the muscle grow faster; the benefit of additional protein diminishes progressively; and surplus protein cannot be stored by the body but only broken down and excreted. Morton et al (2018) agree on the figures: beyond a total protein intake of 1.62 g per kilogram of body weight a day, supplementary protein produced no additional gain in fat-free mass.

Should creatine be stopped before a blood test?

Not one of the sources consulted for this article recommends stopping creatine for a week or for any period. What the sources say is something else: creatine raises blood creatinine, and clinicians should be cautious in interpreting creatinine and estimating kidney function in people taking creatine or with a high meat intake. What can practically be done is to tell the healthcare staff you take creatine when you have blood taken.

I am pregnant and drink coffee or milk tea every day — how much is too much?

Two bodies, two figures, and this article gives both. The Hong Kong Centre for Food Safety (with the Consumer Council, 2013, in Chinese) says that pregnant and breastfeeding women should limit caffeine intake to no more than 200–300 mg a day; EFSA says 200 mg a day. The stricter is the 200 mg. On how much is in a cup, the Centre for Food Safety has two figures: the reference figure in Food Safety Focus issue one hundred and fifty-three (April 2019) is 90 to 200 mg a cup; while the 2013 analysis of 80 samples bought in Hong Kong eateries found ordinary coffee averaging 200 mg a cup with a range of 110 to 380 mg. Both are published by the Centre for Food Safety and this article does not adjudicate.

I am on warfarin or a blood thinner — should I cut down on dark green vegetables?

No. The direction of the NIH ODS vitamin K overview is to keep it consistent: people taking these anticoagulants need to maintain a consistent intake of vitamin K. This article has not told anyone, and will not tell anyone, to cut down on dark green vegetables — the source does not say that. To change your diet or add a supplement, speak to your doctor or pharmacist.

I am taking a "bodybuilding product" and I have side effects — should I stop it at once?

Two sources give two opposite answers, depending on which class the thing in your hand belongs to. If it is a slimming or figure-shaping product already named by the Department of Health and found to contain undeclared Western drug ingredients, the Department's Chinese original reads 「已購買相關產品的市民應立即停止服用」 — anyone who has bought the product should stop taking it at once — and it may be submitted to the Drug Office for disposal. If it is a bodybuilding or muscle-building product claiming to contain steroids or steroid-like substances, the FDA's sentence is in English — it advises consulting a health care professional immediately, because of dangerous withdrawal problems. If you are not sure which class the thing in your hand belongs to, treat it as class 2, because "find someone first" cannot go wrong in either situation.

I take a thiazide diuretic for blood pressure and also calcium and vitamin D — what should I watch for?

Three sources point at the same thing. The Department of Health Drug Office (February 2020) states that thiazide diuretics raise the level of calcium in the body, that this calls for extra care together with high-calcium foods, and that in severe cases it can cause convulsions and coma; the NIH ODS vitamin D overview states that thiazide diuretics decrease urinary calcium excretion and that combining them with vitamin D supplements 「might lead to hypercalcemia」, especially in older adults and in people with compromised renal function or hyperparathyroidism; and the same overview separately states that combining calcium supplements with vitamin D supplements may increase the risk of certain adverse effects. That is a question to take to your next appointment, not a reason to stop a drug by yourself.

Is creatine safe?

The effect figures are clear (a performance improvement of 10% to 20%). On safety, one thing has to be said with it: the position stand cited in this article was written at the request of, and supported by, an American supplement industry body (this article has not obtained that body's own page, and reports the description as recorded in the paper's declaration of interest); and what it says about dehydration, cramping and abnormal kidney function is that there is "no evidence" of it, not that it does not happen. The only independent corroboration in this article is a study from 1999, whose abstract gives no sample size.

#Notes: the original texts

[Note 1] Drug Office of the Department of Health, Basic knowledge of registered drugs (August 2024): the drug regulatory framework, and the statutory definition of a "pharmaceutical product" under the Pharmacy and Poisons Ordinance.

"In Hong Kong, the Department of Health is responsible for regulating the safety, efficacy and quality of all drugs sold in Hong Kong. Drugs are divided into Chinese medicines and non-Chinese medicines (or Western medicines), governed respectively by the Chinese Medicine Ordinance (Chapter 549) and the Pharmacy and Poisons Ordinance (Chapter 138)." (our translation from the Chinese original)

Chinese original:

「在香港，衞生署負責監管在香港銷售的所有藥物的安全、成效和素質。藥物可分為中藥和非中藥（或西藥），它們分別受《中醫藥條例》（第549章）和《藥劑業及毒藥條例》（第138章）所管制。」

"Under the Pharmacy and Poisons Ordinance, a 'pharmaceutical product' — (a) means a substance or combination of substances answering the following description — (i) the representation of the substance or combination of substances, or its condition, indicates that it has properties making it usable for treating or preventing disease in human beings or animals; or (ii) it may be used or administered to human beings or animals with a view to — (A) restoring, correcting or modifying physiological function by pharmacological, immunological or metabolic action; or (B) making a medical diagnosis; and (b) includes advanced therapy products." (our translation from the Chinese original)

Chinese original:

「根據《藥劑業及毒藥條例》，「藥劑製品」— (a) 指符合以下說明的物質或物質組合 — (i) 對該物質或物質組合的表述或其狀況顯示，該物質或物質組合具有的特性，使其可用於治療或預防人類或動物的疾病；或 (ii) 可應用或施用於人類或動物，以期 — (A) 透過藥理、免疫或新陳代謝作用，恢復、矯正或改變生理機能；或 (B) 作出醫學診斷 ; 及 (b) 包括先進療法製品」

[Note 2] The same page: the registration requirements, and the HK-XXXXX registration number.

"A pharmaceutical product must meet the standards of safety, efficacy and quality before it can be registered under the Pharmacy and Poisons Regulations (Chapter 138A). Those requirements exist to ensure that the drugs sold to the public in the market are safe, effective and of quality. An applicant for registration must therefore submit a series of documents for the Board's approval, including but not limited to a description of the product and its composition, the product specifications, the relevant laboratory reports, the manufacturer's licence, and clinical and scientific documents demonstrating the product's safety and efficacy." (our translation from the Chinese original)

Chinese original:

「藥劑製品必須符合安全、成效和素質方面的標準，才能按照《藥劑業及毒藥規例》（第138A章）的規定獲得註冊。有關要求旨在保障市面上出售給公眾的藥物是安全、有效和具素質。因此，申請人在申請註冊時須提交一系列文件，包括但不限於產品的描述及成分、產品規格、相關化驗報告、製造商牌照及證明產品安全和成效的臨床和科學文件等，以供管理局審批。」

"The Board gives a registered drug a registration number in the format HK-XXXXX, and that number must be shown on the drug label. Members of the public can check whether a registration number is printed on the label, and so tell whether the drug is registered." (our translation from the Chinese original)

Chinese original:

「管理局會給予註冊藥物一個格式為HK-XXXXX的註冊編號，該編號必須在藥物標籤上標示。市民可以檢查標籤上是否印有註冊編號，從而識别藥物是否已經註冊。」

[Note 3] Department of Health press release (23 May 2025): a slimming product bought on a social media platform found to contain sibutramine and furosemide, with that release's own instruction to stop taking it.

"Acting on intelligence, the Department of Health purchased a slimming product on a social media platform. Analysis showed the sample to contain sibutramine and furosemide. Both are Part 1 poisons under the Pharmacy and Poisons Ordinance (Chapter 138). / Sibutramine was once used to suppress appetite; because it increases the risk of cardiovascular disease, pharmaceutical products containing sibutramine have been prohibited from use and sale in Hong Kong since November 2010. Furosemide is used to treat heart disease, and its side effects include low blood pressure and electrolyte imbalance. … / The packaging of the product bears no product name, only the English words 「Good health is over wealth」, and it is suspected to be an unregistered pharmaceutical product. The Department of Health will continue to follow up and investigate." (our translation from the Chinese original)

Chinese original:

「衞生署根據情報在社交媒體平台購獲一款減肥產品。化驗結果顯示，樣本含有「西布曲明」和「呋塞米」。兩者均屬《藥劑業及毒藥條例》（第138章）（《條例》）下的第1部毒藥。 「西布曲明」曾用於抑壓食慾，由於會增加心血管疾病的風險，自二○一○年十一月起，含「西布曲明」的藥劑製品已被禁止在香港使用和出售。「呋塞米」用以治療心臟病，副作用包括低血壓和電解質不平衡。… 有關產品的包裝上沒有產品名稱，只有英文字句「Good health is over wealth」，懷疑是未經註冊藥劑製品。衞生署會繼續跟進和調查事件。」

"Members of the public who have bought the product should stop taking it at once, and if they have any doubt or feel unwell after taking it should seek advice from a healthcare professional immediately. During office hours the product may be submitted for disposal to the Drug Office of the Department of Health at Room 1804-06, 18/F, Wing On Kowloon Center, 345 Nathan Road, Kowloon." (our translation from the Chinese original)

Chinese original:

「已購買相關產品的市民應立即停止服用，如有疑問或服用後感到不適，應立即徵詢醫護人員的意見。市民可於辦公時間內，將有關產品交予九龍彌敦道345號永安九龍中心18樓1804-06室衞生署藥物辦公室銷毀。」

[Note 4] From the same set of releases, the instruction to stop taking it in the second-to-last paragraph of the one of 29 January 2026 — read word against word with the 2025 one.

"Members of the public who have bought the above product should stop taking it at once, and if they feel unwell after taking it should seek advice from a healthcare professional. During office hours the product may be submitted for disposal to the Drug Office of the Department of Health at Room 1804-06, 18/F, Wing On Kowloon Center, 345 Nathan Road, Kowloon." (our translation from the Chinese original)

Chinese original:

「已購買上述產品的市民應立即停止服用，如服用有關產品後感到不適，應尋求醫護人員的意見。市民可於辦公時間內，將有關產品交予九龍彌敦道345號永安九龍中心18樓1804-06室衞生署藥物辦公室銷毀。」

[Note 5] Department of Health press release (29 January 2026): the 「KRN+PM」 slimming product found to contain hydrochlorothiazide and fluoxetine, and that release's passage on the risks of buying controlled drugs online.

"The Department of Health is today (29 January) investigating a case of the illegal online sale of a slimming drug containing undeclared controlled drug ingredients, and reminds members of the public not to buy or take the product (pictured), to avoid a risk to health. / Acting on intelligence, the Department of Health earlier purchased a slimming product through an instant messaging app. The product's carton bears the English words 「KRN+PM」 and 「KOREAN PREMIUM」 and contains 30 sealed sachets, each holding seven pills and capsules. The packaging carries Korean text indicating that the product may originate from Korea. / Analysis showed that an orange round pill embossed 「Y|H」 contained hydrochlorothiazide, and that a sample of a green and yellow capsule marked 「TG」 and 「FLM」 contained fluoxetine. Both are Part 1 poisons under the Pharmacy and Poisons Ordinance (Chapter 138). / The product is suspected to be an unregistered pharmaceutical product, and the Department of Health will continue to investigate and take appropriate follow-up action. / Hydrochlorothiazide is used to treat high blood pressure and its side effects include low blood pressure and electrolyte imbalance. Fluoxetine is used to treat depression and may cause hallucinations and insomnia. Pharmaceutical products containing hydrochlorothiazide and fluoxetine may be used only on a doctor's instruction and sold on a doctor's prescription under the supervision of a registered pharmacist at an authorised poisons seller, commonly called a pharmacy." (our translation from the Chinese original)

Chinese original:

「衞生署今日（一月二十九日）正調查一宗網上非法出售含有未標示受管制藥物成分的減肥藥個案，並提醒市民切勿購買或服用該產品（見圖），以免對健康構成風險。 衞生署根據情報，早前透過即時通訊軟件購獲一款減肥產品。該產品的紙盒包裝上印有英文「KRN+PM」及「KOREAN PREMIUM」，內有30個密封包裝袋，每個密封包裝袋內含七顆藥丸和膠囊。產品包裝上有以韓文顯示有關產品可能源自韓國。 化驗結果顯示，一款壓印「Y|H」字樣的橙色圓形藥丸含有「氫氯噻嗪」；一款印有「TG」和「FLM」字樣的綠色/黃色膠囊的樣本則含有「氟西汀」。兩者均屬《藥劑業及毒藥條例》（第138章）（《條例》）下的第1部毒藥。 有關產品懷疑是未經註冊藥劑製品，衞生署會繼續調查事件和採取適當跟進。 「氫氯噻嗪」用以治療高血壓，其副作用包括低血壓和電解質不平衡。「氟西汀」用以治療抑鬱症，可能引起幻覺及失眠。含有「氫氯噻嗪」和「氟西汀」的藥劑製品只可在醫生指示下使用，並憑醫生處方在註冊藥劑師監督下於獲授權毒藥銷售商（一般稱為「藥房」）出售。」

"Buying drugs controlled by law, including slimming drugs, on a website carries health risks: besides the absence of a doctor's assessment of one's own state of health, it is difficult to confirm the legitimate source of the drug, and there is no way of knowing whether it was stored properly in transit (especially drugs requiring cold chain storage), so that its safety, quality and even efficacy cannot be guaranteed." (our translation from the Chinese original)

Chinese original:

「在網站購買受法例管制藥物（包括減肥藥物）有健康風險，除了未經醫生評估個人健康狀況，亦難以確認藥物的正當來源，而且無法得知藥物在運輸過程是否儲貯恰當（尤其須冷鍵保存藥物），其安全、素質以致效能均無法保證。」 (The 「冷鍵」 in the sentence above is as printed in the release, reproduced here without alteration.)

[Note 6] The penalties paragraph of the same release, including the sentence that Part 1 poisons may be sold only in registered pharmacy premises.

"Under the Ordinance, all pharmaceutical products must be registered with the Pharmacy and Poisons Board of Hong Kong before they may be sold in the market. In addition, pharmaceutical products containing Part 1 poisons may be sold only in the registered premises of a pharmacy under the supervision of a registered pharmacist. … The illegal sale of unregistered pharmaceutical products or of Part 1 poisons is a criminal offence, each offence carrying on conviction a maximum fine of 100,000 dollars and two years' imprisonment." (our translation from the Chinese original)

Chinese original:

「根據《條例》，所有藥劑製品須獲香港藥劑業及毒藥管理局註冊，方可於市面銷售。此外，含有第1部毒藥的藥劑製品只可在藥房的註冊處所內由註冊藥劑師監督下銷售。……非法售賣未經註冊藥劑製品或第1部毒藥均屬刑事罪行，每項罪行一經定罪最高罰款100,000元及監禁兩年。」

[Note 7] Drug Office of the Department of Health, vitamins page (December 2024): the vitamin products that are prescription drugs and their dose thresholds, items (a) to (f).

"Some vitamin products are prescription drugs, for example: (a) pharmaceutical products containing vitamin A at a daily dose of not less than 10,000 international units (IU); (b) pharmaceutical products containing vitamin B3 (niacin) at a daily dose of more than 200 mg; (c) pharmaceutical products containing vitamin D at a daily dose of more than 1,000 international units; (d) oral dosage forms of pharmaceutical products containing vitamin K (note: except those containing vitamin K1 or K2 at a daily dose equal to or less than 120 micrograms); (e) pharmaceutical products containing alfacalcidol; (f) pharmaceutical products containing calcitriol." (our translation from the Chinese original)

Chinese original:

「有一些維他命產品屬處方藥物，例如： (a)含維生素A而每日劑量不低於10,000國際單位(IU)的藥劑製品； (b)含維生素B3（煙酸）而每日劑量超過200毫克的藥劑製品； (c)含維生素D而每日劑量超過1,000國際單位的藥劑製品； (d)含維生素K的口服劑型藥劑製品（注意：含維生素K1或K2而每日劑量相等或少於120微克除外） (e)含阿法骨化醇的藥劑製品； (f)含骨化三醇的藥劑製品；」

[Note 8] All seven items of the same page's checklist on buying vitamins, and the two closing sentences immediately following.

"There is a great variety of vitamin products on the market, and the following points should be noted when buying and taking them: 1. Ask yourself what the purpose of taking a vitamin is. Is extra supplementation really needed, or is it a psychological effect? 2. Look carefully at the kinds and amounts of vitamins in the product, and whether they suit the age and physical condition of the person taking them. Before buying or taking any vitamin product, refer to the instructions on the packaging or in the leaflet, and seek professional advice from a healthcare professional. 3. Do not take more than the recommended daily dose. 4. If you are pregnant or breastfeeding, seek advice from a healthcare professional before using any vitamin product. 5. Store vitamin products as instructed, so that they do not lose their effect. 6. Some vitamin products are prescription drugs, for example: [items (a) to (f) quoted above]. 7. Consult your doctor before taking any vitamin over the long term." (our translation from the Chinese original)

Chinese original:

「市面供應的維他命產品十分多，我們在選購及服用時要留意以下幾點：

1. 問問自己，服用維他命的目的為何？是真的需要額外補充嗎？還是有種心理作用？
2. 看清楚產品內所含的維他命種類及份量，是否符合服用者的年齡及身體狀況。在選購或服用任何維他命產品前，應參考產品的包裝或說明書上的指示，以及徵詢醫護人員的專業意見。
3. 不可服用超過建議的每日劑量。
4. 如果您正在懷孕或餵哺母乳，請在使用任何維他命產品前徵詢醫護人員意見。
5. 要按照指示貯存維他命產品，以免失去效用。
6. 有一些維他命產品屬處方藥物，例如：〔上引 (a) 至 (f) 六項〕
7. 如要長期服用任何的維他命，應事前請教你的醫生。」

"In fact, in normal circumstances, provided the diet is balanced, we can take in enough vitamins from everyday food without extra supplementation. Vitamins, like other drugs, must be stored properly, so that children do not take them by accident." (our translation from the Chinese original)

Chinese original:

「其實，在正常情況下，只要飲食均衡，我們是可以從日常食物中攝取足夠的維他命而毋須額外補充的。維他命如其他藥物一樣需要妥善貯存，以免兒童誤服而發生意外。」

[Note 9] The ATBC trial (Finland, 29,133 male smokers).

「Unexpectedly, we observed a higher incidence of lung cancer among the men who received beta carotene than among those who did not (change in incidence, 18 percent; 95 percent confidence interval, 3 to 36 percent).」 「Total mortality was 8 percent higher (95 percent confidence interval, 1 to 16 percent) among the participants who received beta carotene than among those who did not, primarily because there were more deaths from lung cancer and ischemic heart disease.」 ⚠️ 同一段亦報告了維他命E那一臂的結果，同下文兩節直接相關：「Fewer cases of prostate cancer were diagnosed among those who received alpha-tocopherol than among those who did not. … Alpha-tocopherol had no apparent effect on total mortality, although more deaths from hemorrhagic stroke were observed among the men who received this supplement than among those who did not.」 作者結論句：「We found no reduction in the incidence of lung cancer among male smokers after five to eight years of dietary supplementation with alpha-tocopherol or beta carotene. In fact, this trial raises the possibility that these supplements may actually have harmful as well as beneficial effects.」

[Note 10] The CARET trial (18,314 people).

「The active-treatment group had a relative risk of lung cancer of 1.28 (95 percent confidence interval, 1.04 to 1.57; P=0.02), as compared with the placebo group. There were no statistically significant differences in the risks of other types of cancer. In the active-treatment group, the relative risk of death from any cause was 1.17 (95 percent confidence interval, 1.03 to 1.33); of death from lung cancer, 1.46 (95 percent confidence interval, 1.07 to 2.00); and of death from cardiovascular disease, 1.26 (95 percent confidence interval, 0.99 to 1.61). On the basis of these findings, the randomized trial was stopped 21 months earlier than planned; follow-up will continue for another 5 years.」 作者結論句：「After an average of four years of supplementation, the combination of beta carotene and vitamin A had no benefit and may have had an adverse effect on the incidence of lung cancer and on the risk of death from lung cancer, cardiovascular disease, and any cause in smokers and workers exposed to asbestos.」

[Note 11] The single sentence into which USPSTF (21 June 2022) put that history.

「The USPSTF recommends against the use of beta carotene or vitamin E supplements for the prevention of cardiovascular disease or cancer.」——評級 D

[Note 12] The VITAL trial: the cancer and cardiovascular results for vitamin D, the fracture result, and the sentence on whether the baseline vitamin D level changed the effect.

VITAL 維他命D（Manson 等，NEJM 2019）： 「Supplementation with vitamin D was not associated with a lower risk of either of the primary end points. During a median follow-up of 5.3 years, cancer was diagnosed in 1617 participants (793 in the vitamin D group and 824 in the placebo group; hazard ratio, 0.96; 95% confidence interval [CI], 0.88 to 1.06; P=0.47). A major cardiovascular event occurred in 805 participants (396 in the vitamin D group and 409 in the placebo group; hazard ratio, 0.97; 95% CI, 0.85 to 1.12; P=0.69).」 作者自己的結論句：「Supplementation with vitamin D did not result in a lower incidence of invasive cancer or cardiovascular events than placebo.」

「Supplemental vitamin D3, as compared with placebo, did not have a significant effect on total fractures (which occurred in 769 of 12,927 participants in the vitamin D group and in 782 of 12,944 participants in the placebo group; hazard ratio, 0.98; 95% confidence interval [CI], 0.89 to 1.08; P = 0.70), nonvertebral fractures (hazard ratio, 0.97; 95% CI, 0.87 to 1.07; P = 0.50), or hip fractures (hazard ratio, 1.01; 95% CI, 0.70 to 1.47; P = 0.96).」 結論句：「Vitamin D3 supplementation did not result in a significantly lower risk of fractures than placebo among generally healthy midlife and older adults who were not selected for vitamin D deficiency, low bone mass, or osteoporosis.」

「There was no modification of the treatment effect according to baseline characteristics, including age, sex, race or ethnic group, body-mass index, or serum 25-hydroxyvitamin D levels.」

[Note 13] The VITAL trial: the marine n-3 result, and the whole of the sentence containing its six secondary endpoints.

「During a median follow-up of 5.3 years, a major cardiovascular event occurred in 386 participants in the n-3 group and in 419 in the placebo group (hazard ratio, 0.92; 95% confidence interval [CI], 0.80 to 1.06; P=0.24). Invasive cancer was diagnosed in 820 participants in the n-3 group and in 797 in the placebo group (hazard ratio, 1.03; 95% CI, 0.93 to 1.13; P=0.56).」 結論句：「Supplementation with n-3 fatty acids did not result in a lower incidence of major cardiovascular events or cancer than placebo.」

「In the analyses of key secondary end points, the hazard ratios were as follows: for the expanded composite end point of cardiovascular events, 0.93 (95% CI, 0.82 to 1.04); for total myocardial infarction, 0.72 (95% CI, 0.59 to 0.90); for total stroke, 1.04 (95% CI, 0.83 to 1.31); for death from cardiovascular causes, 0.96 (95% CI, 0.76 to 1.21); and for death from cancer (341 deaths from cancer), 0.97 (95% CI, 0.79 to 1.20). In the analysis of death from any cause (978 deaths overall), the hazard ratio was 1.02 (95% CI, 0.90 to 1.15). No excess risks of bleeding or other serious adverse events were observed.」

[Note 14] The COSMOS trial (21,442 people).

「During a median follow-up of 3.6 y, invasive cancer occurred in 518 participants in the MVM group and 535 participants in the placebo group (HR: 0.97; 95% CI: 0.86, 1.09; P = 0.57). … The composite CVD outcome occurred in 429 participants in the MVM group and 437 participants in the placebo group (HR: 0.98; 95% CI: 0.86, 1.12). MVM use did not significantly affect all-cause mortality (HR: 0.93; 95% CI: 0.81, 1.08).」 結論句：「A daily MVM supplement, compared with placebo, did not significantly reduce the incidence of total cancer among older men and women.」

[Note 15] The WHI trial (36,282 postmenopausal women): the intention-to-treat result, the sensitivity analysis with non-adherence censored, and the sentence on stratification by baseline level.

「Hip bone density was 1.06 percent higher in the calcium plus vitamin D group than in the placebo group (P<0.01).」 「Intention-to-treat analysis indicated that participants receiving calcium plus vitamin D supplementation had a hazard ratio of 0.88 for hip fracture (95 percent confidence interval, 0.72 to 1.08), 0.90 for clinical spine fracture (0.74 to 1.10), and 0.96 for total fractures (0.91 to 1.02).」 「The risk of renal calculi increased with calcium plus vitamin D (hazard ratio, 1.17; 95 percent confidence interval, 1.02 to 1.34).」 結論句：「Among healthy postmenopausal women, calcium with vitamin D supplementation resulted in a small but significant improvement in hip bone density, did not significantly reduce hip fracture, and increased the risk of kidney stones.」

「Censoring data from women when they ceased to adhere to the study medication reduced the hazard ratio for hip fracture to 0.71 (95 percent confidence interval, 0.52 to 0.97).」

「Effects did not vary significantly according to prerandomization serum vitamin D levels.」

[Note 16] The scope the USPSTF 2022 recommendation defines for itself, and the passage it writes on the same page about how to implement it.

「This recommendation applies to community-dwelling, nonpregnant adults. It does not apply to children, persons who are pregnant or may become pregnant, or persons who are chronically ill, are hospitalized, or have a known nutritional deficiency.」 「The USPSTF separately recommends that all persons who are planning or capable of pregnancy take a daily supplement containing 0.4 to 0.8 mg (400 to 800 μg) of folic acid.」 「Persons who have an acute or chronic illness may require additional vitamin, mineral, or multivitamin supplementation as part of management of their condition, which goes beyond supplementation for the prevention purposes addressed by this recommendation.」

「Do not use beta carotene or vitamin E supplements to prevent cardiovascular disease or cancer.」 「The evidence is insufficient to recommend for or against the use of multivitamin supplements, or single- or paired-nutrient supplements (other than beta carotene and vitamin E), to prevent cardiovascular disease or cancer. Clinicians should use their clinical judgement to determine whether or not vitamin supplements should be recommended for an individual patient.」

[Note 17] The USPSTF 2018 fracture recommendation: the patient population, the potential harms section, and the definition of 「supplementation」.

「These recommendations apply to community-dwelling, asymptomatic adults. "Community-dwelling" is defined as not living in a nursing home or other institutional care setting. These recommendations do not apply to persons with a history of osteoporotic fractures, increased risk for falls, or a diagnosis of osteoporosis or vitamin D deficiency.」

「The WHI trial found a statistically significant increase in the incidence of kidney stones in women taking vitamin D and calcium compared with women taking placebo. For every 273 women who received supplementation over a 7-year follow-up period, 1 woman was diagnosed with a urinary tract stone.」 「In a separate recommendation statement, the USPSTF found that vitamin D supplementation does not reduce the number of falls or the number of persons who experience a fall. A single study suggested that an annual high dose of vitamin D (500,000 IU) may even be associated with a greater number of injurious falls and a greater number of persons experiencing falls and fractures. The USPSTF now recommends against vitamin D supplementation to prevent falls in community-dwelling older adults.」

「Supplementation refers to the empiric use of dietary supplements without knowledge of or reference to an individual’s diet, nutritional status, or serum levels of micronutrients.」 「Although the evidence does not support supplementation with vitamin D with or without calcium for the prevention of fractures or falls in community-dwelling postmenopausal women and men age 60 years or older, ensuring adequate vitamin D and calcium intake is important for bone and overall health. The National Academy of Medicine has established recommended daily allowances for these nutrients, which range from 600 IU to 800 IU for vitamin D and 1,000 mg to 1,200 mg for calcium. The recommended daily allowance refers to all dietary sources, including food, beverages, and dietary supplements, and it is important that all persons have vitamin D and calcium intake that meets the recommended daily allowance of these nutrients.」

[Note 18] Drug Office vitamins page: the misconception about vitamin C, colds and kidney stones; the sentence about not taking too much and the exceptions needing extra supplementation; and the instruction to stop for peripheral neuropathy from vitamin B6.

"Misconception two: it is popularly believed that vitamin C can prevent a cold or help a sufferer recover quickly. That remains medically unproven, while taking large amounts of vitamin C over a long period may cause kidney stones." (our translation from the Chinese original)

Chinese original:

「謬誤(二) 大衆一般認爲維他命 C 能預防感冒或有助感冒患者迅速康復。這在醫學上仍未能證實，但長期大量服食維他命 C 郤有可能導致腎石。」 (The character 「郤」 in the sentence above is as printed on that page, reproduced here as found.)

"Vitamins should not be taken in excess, and children in particular must not be given excessive vitamin A and D." / "In some special circumstances the body needs extra vitamin supplementation. Women who are pregnant or breastfeeding, for instance, have a greater need for vitamins; and people who smoke also need more vitamin C." (our translation from the Chinese original)

Chinese original:

「不應服用過量的維他命，尤其不可以讓兒童服食過量的維他命 A 及 D。」 「在一些特別情況下，人體會需要額外的維他命補充。例如懷孕或哺乳期間的婦女，對維他命的需求會比較大；而吸煙人士對維他命 C 的需要也比較多。」

"When taking vitamin products, be alert to possible adverse reactions or side effects. Peripheral neuropathy, for instance, is a known side effect of vitamin B6, its symptoms being tingling, burning or numbness, usually in the hands or feet. So if you are taking any product containing vitamin B6 and tingling, burning or numbness occurs, stop taking it at once and seek advice from a healthcare professional as soon as possible." (our translation from the Chinese original)

Chinese original:

「當服用維他命產品時，要注意可能出現的不良反應或副作用。例如，周邊神經病變是維他命B6 的一個已知副作用，其症狀是刺痛、灼熱或麻痺，通常出現在手或腳。因此，如果您正服用任何含有維他命B6的產品，當出現刺痛、灼熱或麻痺的情況時，應立即停止服用，並儘快諮詢醫護人員意見。」

[Note 19] NIH ODS vitamin D overview: the Food and Nutrition Board's statement that effects are possible below the UL, the manifestations of vitamin D toxicity, and the passage on calcium with vitamin D together with the qualifying sentence immediately after it.

「While acknowledging that signs and symptoms of toxicity are unlikely at daily intakes below 250 mcg (10,000 IU), the FNB noted that even vitamin D intakes lower than the ULs might have adverse health effects over time. The FNB recommended avoiding serum 25(OH)D levels above approximately 125 to 150 nmol/L (50–60 ng/mL), and it found that even lower serum levels (approximately 75–120 nmol/L [30–48 ng/mL]) are associated with increases in rates of all-cause mortality, risk of cancer at some sites (e.g., pancreas), risk of cardiovascular events, and number of falls and fractures among older adults.」

「Vitamin D toxicity can cause hypercalcemia, hypercalciuria, and high serum 25(OH)D concentrations; in extreme cases, it may lead to renal failure, calcification of soft tissues, cardiac arrhythmias, and death. Vitamin D toxicity is almost always a result of excessive intakes of vitamin D through supplements. Taking calcium supplements in combination with vitamin D supplements may increase the risk of certain adverse effects.」

「The combination of high intakes of calcium (about 2,100 mg/day from food and supplements) with moderate amounts of vitamin D (about 19 mcg [765 IU]/day from food and supplements) increased the risk of kidney stones by 17% over 7 years among 36,282 postmenopausal women who were randomly assigned to take 1,000 mg/day calcium and 10 mcg (400 IU)/day vitamin D or a placebo. However, other, shorter (from 24 weeks to 5 years) clinical trials of vitamin D supplementation alone or with calcium in adults found greater risks of hypercalcemia and hypercalciuria, but not of kidney stones.」

[Note 20] Misconception one on the Drug Office's vitamins page.

"Misconception one: many parents believe that taking more vitamins will give a child an appetite, make them taller, more alert and cleverer. In fact none of that has any scientific basis. On the contrary, taking vitamin A and D over a long period and in excess can cause disease, and even serious consequences such as high blood pressure and kidney failure." (our translation from the Chinese original)

Chinese original:

「謬誤(一) 很多家長以為多服維他命能令兒童開胃、增高、提神及更聰明。其實這些全都沒有科學根據。相反，長期及過量服用維他命 A 和 D 能導致疾病，甚至高血壓及腎衰竭等嚴重後果。」

[Note 21] NIH ODS vitamin E overview: the basis on which the UL was set, and the note to the vitamin A table.

「The FNB has established ULs for vitamin E based on the potential for hemorrhagic effects (see Table 3). The ULs apply to all forms of supplemental alpha-tocopherol, including the eight stereoisomers present in synthetic vitamin E. Doses of up to 1,000 mg/day (1,500 IU/day of the natural form or 1,100 IU/day of the synthetic form) in adults appear to be safe, although the data are limited and based on small groups of people taking up to 3,200 mg/day of alpha-tocopherol for only a few weeks or months. Long-term intakes above the UL increase the risk of adverse health effects. Vitamin E ULs for infants have not been established.」

「These ULs apply only to products from animal sources and supplements whose vitamin A comes entirely from retinol or its ester forms, such as retinyl palmitate. However, many dietary supplements (such as multivitamins) do not provide all of their vitamin A in retinol or its ester forms. For example, the vitamin A in some supplements consists partly or entirely of beta-carotene. In such cases, the percentage of retinol or retinyl ester in the supplement should be used to determine whether an individual’s vitamin A intake exceeds the UL. For example, a supplement whose label indicates that the product contains 3,000 mcg RAE vitamin A and that 60% of this vitamin A comes from beta-carotene (and therefore 40% comes from retinol or retinyl ester) provides 1,200 mcg RAE of preformed vitamin A. That amount is above the UL for children from birth to 8 years but below the UL for older children and adults.」

[Note 22] NIH ODS: why beta-carotene has no UL (together with how it differs from preformed vitamin A), and why vitamin K has no UL — two cases of "no upper limit", for different reasons.

「Unlike preformed vitamin A, beta-carotene is not known to be teratogenic or lead to reproductive toxicity. The most common effect of long-term, excess beta-carotene is carotenodermia, a harmless condition in which the skin becomes yellow-orange. This condition can be reversed by discontinuing beta-carotene ingestion. However, the ATBC trial found that supplementation with a large amount of beta-carotene (20 mg/day), with or without 50 mg/day vitamin E, for 5–8 years increased the risk of lung cancer and mortality (mainly from lung cancer and ischemic heart disease) in male smokers. The CARET trial also showed that supplementation with a large amount of beta-carotene (30 mg/day) plus 7,500 mcg RAE (25,000 IU)/day retinyl palmitate for 4–8 years in current and former smokers as well as some men occupationally exposed to asbestos increased the risk of lung cancer and death from lung cancer.」

「The FNB has not established ULs for beta-carotene and other provitamin A carotenoids. However, the FNB advises against the use of beta-carotene supplements for the general population, except as a provitamin A source to prevent vitamin A deficiency.」

「The FNB did not establish ULs for vitamin K because of its low potential for toxicity. In its report, the FNB stated that "no adverse effects associated with vitamin K consumption from food or supplements have been reported in humans or animals."」

[Note 23] USPSTF 2022's own harms section, both paragraphs in full.

「Excessive doses of vitamin supplements can cause several known adverse effects; for example, moderate doses of vitamin A supplements may reduce bone mineral density, and high doses may be hepatotoxic or teratogenic. Vitamin D has potential harms, such as a risk of hypercalcemia and kidney stones, when given at high doses. The potential for harm from other supplements at high doses should be carefully considered.」

「The USPSTF also reviewed the evidence on the harms of vitamin and mineral supplements. For many supplements there was little to no evidence of serious harms. The most serious harm identified was increased cardiovascular disease mortality and increased risk of lung cancer in persons who smoke or had workplace asbestos exposure, associated with beta carotene supplementation at doses of 30 and 20 mg/d. One of these trials also co-administered vitamin A at a dose of 25,000 IU/d, which exceeds the current tolerable upper intake level for vitamin A in adults. A minor harm of beta carotene was orange discoloration of the skin. Two cohort studies in women showed a statistically nonsignificant increased risk of hip fracture associated with vitamin A supplementation. Two trials showed an increased risk of hemorrhagic stroke associated with vitamin E supplementation at doses of 111 and 200 IU daily, and 1 cohort study found that a high intake of vitamin B6 (≥35 mg/d) was associated with an increased risk of hip fracture compared with a low intake (<2 mg/d). One trial and 2 cohort studies reported an increased risk of kidney stones in persons taking vitamin D. In the cohort studies, this risk was only associated with vitamin D doses of 1000 IU/d or more. Two cohort studies in men suggest an association between vitamin C supplementation and kidney stones. The evidence on an association between calcium use and kidney stones was mixed.」

[Note 24] Drug Office of the Department of Health, on interactions between drugs and food and drink (February 2020): the difference between red yeast rice and red rice, and monacolin K and lovastatin.

"Red yeast rice is not the same as red rice; red rice is unmilled or half-milled paddy (brown rice) with the red bran attached. Red rice may be eaten as a staple food, but red yeast rice must not be." (our translation from the Chinese original)

Chinese original:

「紅麴米有別於「紅米」；紅米是未經碾磨或已半碾磨的稻穀（糙米），並附著「紅色的米糠」。雖然紅米可以作為主食，但是紅麴米是不可作為主食之用。」

"Modern medicine has also found that the substance monacolin K in red yeast rice helps lower blood cholesterol. In fact monacolin K exists in two chemical forms, an acid form and a lactone form. The lactone form is chemically identical to the drug called lovastatin (figure). … In other words, red yeast rice may contain the pharmacologically active substance lovastatin." / "Common foods and health products containing red yeast rice may all contain variable amounts of lovastatin. People taking products containing red yeast rice should be careful, because they may experience drug effects similar to those of lovastatin; and red yeast rice may also interact with other drugs." / "The ingredient lovastatin itself affects liver function. Pregnant women and breastfeeding mothers should not take pharmaceutical products containing lovastatin. In fact red yeast rice products, containing lovastatin, may also affect the liver. People with liver disease, pregnant women and breastfeeding mothers should be particularly careful about eating red yeast rice products." / "Lovastatin itself may interact with other drugs; products containing red yeast rice may also affect other drugs and vice versa. For example, pharmaceutical products containing lovastatin should not be taken together with drugs that may inhibit liver enzymes (itraconazole, ketoconazole, erythromycin and gemfibrozil, for instance). Taken together, there is a higher risk of muscle inflammation and other side effects." / "If you take a drug containing lovastatin, or another cholesterol-lowering drug, and are also taking red yeast rice, the cholesterol-lowering effect may be increased to some degree (an additive effect). If you are taking red yeast rice, please tell your doctor, so that appropriate advice can be given." / "Under the Pharmacy and Poisons Ordinance, statins (including pharmaceutical products containing lovastatin) are prescription drugs." (our translation from the Chinese original)

Chinese original:

「現代醫學亦發現紅麴米內的物質「莫納可林K」有助於降低血液中的膽固醇水平。事實上，莫納可林Ｋ有兩種化學形式存在：酸性形式和內酯形式。內酯的形式於化學上與名為「洛伐他汀」的藥物完全相同（圖）。…換句話說，紅麴米可會含有活性的藥理物質洛伐他汀。」 「常見的含紅麴米食品或保健品內，都可能包含不定份量的「洛伐他汀」。服用含紅麴米產品的人都應該謹慎，因為他們可能會感受到類似於洛伐他汀的藥物效應；紅麴米亦可能與其他藥物有相互作用。」 「洛伐他汀這個成分本身會影響肝功能。孕婦或哺乳期的母親不應服用含有洛伐他汀的藥劑製品。事實上，紅麴米產物（含洛伐他汀）也有機會影響到肝臟。肝病患者、孕婦或哺乳的母親，在食用紅麴米的產品時應特別小心。」 「洛伐他汀本身可能與其他藥物產生相互作用；含紅麴米產品也可能會影響其他藥物，及反之亦然。舉個例子，含洛伐他汀的藥劑製品不應與可能抑制肝酶的藥物（如：伊曲康唑、酮康唑、紅霉素、吉非貝齊）一起服用。如果同時服用，則會有較高風險出現肌肉發炎，及其他副作用。」 「如果你服用含洛伐他汀的藥物，或其他降膽固醇藥，但同時也服用紅麴米；則有可能在不同程度上，增加降低膽固醇的效應（疊加作用）。如你正在服用紅麴米，請要告訴醫生；以便給予你適當的意見。」 「根據藥劑業及毒藥條例，他汀類藥物（包括：含洛伐他汀的藥劑製品）是處方藥。」

[Note 25] The two paragraphs on foods containing calcium on the same page — calcium reducing the effect of drugs, and certain drugs raising the level of calcium in the body.

"Calcium in food may reduce the body's ability to absorb drugs. Typical examples include the antibiotics tetracycline, ciprofloxacin and levofloxacin, whose potency may be reduced if calcium-rich food is eaten when they are taken. Drugs of low bioavailability, such as the bisphosphonates (alendronate, risedronate and ibandronate), are also particularly affected by such foods. These drugs that interact with calcium are prescription drugs and should be taken as the doctor directs. Taking calcium-rich foods or supplements at the same time should be avoided, and separating them by at least 30 minutes is advised." (our translation from the Chinese original)

Chinese original:

「食物中的鈣質可能減低人體吸收藥物的能力。典型的例子包括四環素、環丙沙星、左氧氟沙星這幾種抗生素，服用時如進食鈣質豐富的食物，藥物效力可能被減低。另外，一些生體可用率較低的藥物，例如雙膦酸鹽類(即：阿侖膦酸鹽、利塞膦酸鹽、班膦酸鹽)，也特別受這些食物影響。這些與鈣有相互作用的藥物是處方藥；應按照醫生的指示服用。應避免同時攝取含豐富鈣質的食物或補充品；並建議把攝取時間分隔開至少30分鐘。」

"Some drugs may raise the level of calcium in the body, for example antacids (those containing calcium carbonate), thiazide diuretics (hydrochlorothiazide, indapamide, metolazone), lithium and thyroxine. Antacids are non-prescription drugs, while thiazide diuretics, lithium and thyroxine are prescription drugs. When taking these drugs, extra care is needed with calcium-rich foods, to avoid an excessive level of calcium in the body causing nausea and vomiting, excessive urination, constipation, abdominal pain, and even convulsions and coma." (our translation from the Chinese original)

Chinese original:

「有些藥物可能會提高體內鈣質的水平，例如制酸劑(如：含有碳酸鈣的)、噻嗪類利尿藥(氫氯噻嗪、吲達帕胺、美托拉宗)、鋰和甲狀腺素。制酸劑為非處方藥；而噻嗪類利尿藥、鋰和甲狀腺素則是處方藥。服用這些藥物時，如進食含鈣質豐富的食物，就要加倍留意，以避免體內鈣質水平過高，引致噁心和嘔吐、多尿、便秘、腹痛，甚至抽筋和昏迷。」

[Note 26] The United States National Center for Complementary and Integrative Health (NCCIH, May 2025) on St John's wort: its summarising sentence, the complete list of the nine classes of drug, the "Keep in Mind" section, and the passage on why people take it.

「It has been clearly shown that St. John’s wort can interact in dangerous, sometimes life-threatening ways with a variety of medicines.」

「For most adults who are not taking any kind of medicine, St. John's wort appears to be safe when used for up to 12 weeks, and some studies indicate that it can be used safely for a year or more. If taken orally in large doses or applied to the skin, St. John's wort might cause severe skin reactions after sun exposure. Other side effects can include diarrhea, dizziness, trouble sleeping, restlessness, and skin tingling. If you take any type of medicine, talk with your health care provider before using St. John's wort or other herbal products; some herbs and medicines interact in harmful ways. For example, St. John's wort can weaken the effects of many medicines, including crucially important medicines such as: Some antidepressants, including amitriptyline and bupropion Birth control pills Cyclosporine, which prevents the body from rejecting transplanted organs Some drugs used to prevent seizures, including phenytoin and carbamazepine Some heart medications, including digoxin and ivabradine Some HIV drugs, including indinavir and nevirapine Some cancer medications, including irinotecan, imatinib, and docetaxel Warfarin, an anticoagulant (blood thinner) Certain statins, including simvastatin In addition, taking St. John's wort with certain antidepressants or other drugs that affect serotonin (a substance produced by some nerve cells) may lead to increased serotonin-related side effects, which can be serious. It may be unsafe to use St. John's wort during pregnancy because it may increase the risk of birth defects. Breastfeeding infants of mothers who take St. John's wort can experience colic, drowsiness, and lethargy.」

「Depression can be a serious illness. If you or someone in your family may have depression, consult a health care provider.」 「Take charge of your health—talk with your health care providers about any complementary health approaches you use. Together, you can make shared, well-informed decisions.」 「Although it is important to tell your health care providers about any complementary health approaches you use, this is especially crucial for St. John’s wort because this herb interacts with so many medicines. Interactions with St. John’s wort can weaken the effects of life-saving medicines or cause dangerous side effects.」

「St. John’s wort appears to be more effective than a placebo (an inactive substance) and as effective as standard antidepressant medications for mild or moderate depression. It’s uncertain whether this is true for severe depression or for time periods longer than 12 weeks.」

[Note 27] Consumer Council CHOICE issue 594 (April 2026): what protein powder is, the four recommended protein intakes, and the sentence that it will not make the muscle grow faster.

"Protein powder may be described as a concentrated form of food, generally made by separating the protein out of protein-rich foods such as milk and beans through extraction, filtration, concentration and drying, and then making it into a powder that keeps more easily. The main ingredient of most protein powders on the market is whey protein, pea protein, soy protein and the like. The process likewise begins by extracting the ingredient from milk or beans, and after processing various additives are put in, including sweeteners (also called sugar substitutes, such as sucralose, acesulfame K and aspartame), thickeners, emulsifiers and flavourings; and some products also add functional ingredients such as caffeine, creatine and beta-alanine." (our translation from the Chinese original)

Chinese original:

「蛋白粉可以說是「食物的濃縮版」，一般從奶、豆類等含豐富蛋白質的食物中，透過萃取、過濾、濃縮與乾燥等工序，將當中的蛋白質分離出來，再製成較易保存的粉末。市面上大部分蛋白粉的主要成分是乳清蛋白（whey protein）、豌豆蛋白、大豆蛋白等。其製作過程也是先從牛奶或豆類中萃取成分，經處理後再加入不同的添加劑，包括甜味劑（又稱代糖，例如三氯半乳蔗糖（sucralose）、醋磺內酯鉀（acesulfame K）、阿斯巴甜（aspartame）等）、增稠劑、乳化劑、香料；另外亦有部分產品會加入咖啡因、肌酸、β-丙氨酸等功能性成分。」

"When buying protein powder, consumers should note its main ingredients, including the source of the protein and the additives, so as to match their own health needs." (our translation from the Chinese original)

Chinese original:

「消費者在選購蛋白粉時，應留意其主要成分，包括蛋白質的來源、添加劑等，以配合自身的健康需要。」

"People of different ages, different activity levels and different states of health have different protein requirements. The following are basic recommended protein intakes drawn from various nutritional studies: • Generally healthy adults (18 to 64): about 0.8 g to 1 g per kilogram of body weight a day (depending on physical activity). • Children, adolescents, pregnant women and breastfeeding women: more protein than an ordinary adult, to support growth and development. • People who exercise regularly or want to build muscle: 1.4 g to 2.0 g per kilogram of body weight a day. • Older people: to prevent sarcopenia, the protein requirement is usually higher, and 1.0 g to 1.2 g per kilogram of body weight a day is recommended (with suitable exercise, muscle mass is maintained more effectively)." (our translation from the Chinese original)

Chinese original:

「不同年齡、不同活動量和不同健康狀況的人士對蛋白質的需求各有不同，以下為參考不同營養學研究所得的基本蛋白質建議攝入量： • 一般健康成年人（18歲至64歲）：每日每公斤體重約需0.8克至1克。（視乎體能活動量） • 兒童、青少年、孕婦及授乳婦女：比一般成年人需要更多蛋白質，以促進生長和發育。 • 有運動習慣／想增肌的人士：每日每公斤體重需 1.4克至2.0克。 • 長者：為預防肌少症（Sarcopenia），蛋白質需求通常較高，建議每日每公斤體重需攝取1.0克至1.2 克（配合適當運動，可更有效地維持身體的肌肉量）。」

"It is worth noting that even where an ordinary person takes in more than the basic requirement, it will not make the muscle grow faster; the benefit of additional protein diminishes progressively, and surplus protein cannot be stored by the body but only broken down and excreted." (our translation from the Chinese original)

Chinese original:

「值得注意的是，一般人即使攝入超過基本所需分量，也不會讓肌肉「長得更快」，額外的蛋白質營養所帶來的效果會逐漸遞減，多餘的蛋白質不能被身體儲存，只能被分解和排出體外。」

[Note 28] Morton et al (Br J Sports Med 2018): the ceiling of 1.62 g, and the effects supplementary protein does have.

「Protein supplementation beyond total protein intakes of 1.62 g/kg/day resulted in no further RET-induced gains in FFM.」 ⚠️ 這個天花板有一個人群範圍，寫在同一份摘要的結論段，本文一併照錄：「Dietary protein supplementation significantly enhanced changes in muscle strength and size during prolonged RET in healthy adults.」而範圍限定字是「健康成年人」。下面那條數用的 1.62 g/kg 天花板，就是在這個範圍之內得出來的。 ⚠️ 同一份摘要緊接住的一句，講明這個效果對邊些人細些、對邊些人大些：「The impact of protein supplementation on gains in FFM was reduced with increasing age (-0.01 kg (-0.02,-0.00), p=0.002) and was more effective in resistance-trained individuals (0.75 kg (0.09, 1.40), p=0.03).」

「Data from 49 studies with 1863 participants showed that dietary protein supplementation significantly (all p<0.05) increased changes (means (95% CI)) in: strength-one-repetition-maximum (2.49 kg (0.64, 4.33)), FFM (0.30 kg (0.09, 0.52)) and muscle size-muscle fibre cross-sectional area (CSA; 310 µm2 (51, 570)) and mid-femur CSA (7.2 mm2 (0.20, 14.30)) during periods of prolonged RET.」

[Note 29] The same Consumer Council article: the explanation of DIAAS, and the sentence that protein powder should not be the only source of protein.

"A DIAAS of 100 or above indicates that the food is a high-quality complete protein, supplying all the amino acids the body needs. Conversely, a lower DIAAS score means that the food alone cannot supply all the necessary amino acids, and so is not suitable as the only source of protein in the daily diet." / "Plant proteins generally score lower on DIAAS and are generally harder for the body to digest and absorb than animal proteins. But research indicates that taking a mixture of different plant proteins can make up the amino acids that any one source lacks." (our translation from the Chinese original)

Chinese original:

「DIAAS達100或以上表示該食品為高品質且完整的蛋白質，能補充身體所必須的全部氨基酸。相反，若DIAAS評分較低，則代表單靠該食物未能為身體補充必須的全部氨基酸，因此不適合作為日常飲食中唯一的蛋白質來源。」 「植物蛋白的DIAAS評分普遍較低，一般較動物性蛋白更難被身體消化和吸收。但研究指攝取「混合不同的植物蛋白」，可補足不同來源所缺乏的氨基酸。」

"At the same time, consumers should not make protein powder their only source of protein, and should keep to a balanced diet and take protein from a variety of foods, so as to obtain the other nutrients beneficial to the body besides protein." (our translation from the Chinese original)

Chinese original:

「同時，消費者亦不宜將蛋白粉作為唯一的蛋白質來源，應保持均衡飲食，從多元化的食物中攝取蛋白質，藉此獲得除蛋白質以外其他對身體有益的營養素。」

[Note 30] The same Consumer Council article on sarcopenia and age.

"This change begins at about the age of 30 and accelerates after 60, and by 80 as much as 30% of muscle mass may have been lost." / "Some older people cannot get enough protein from their everyday diet because of a decline in appetite, in eating or in digestion; and protein powder is easy to swallow and more easily absorbed, and so has become increasingly popular with older people." / "Research suggests that older people generally may raise their daily protein intake and undertake resistance training in order to maintain muscle mass. But note that without exercise, simply increasing protein intake has in fact a very limited effect on maintaining muscle." (our translation from the Chinese original)

Chinese original:

「這種變化大約從 30 歲開始，並在 60 歲後加速，到 80 歲時肌肉量更有可能流失多達 30%。」 「部分長者因食慾、進食或消化能力下降，未能從日常飲食攝取足夠蛋白質；而蛋白粉容易吞嚥和較易吸收，因而愈來愈受長者歡迎。」 「研究建議一般長者可以提升每日的蛋白質攝入量，並進行阻力訓練，以維持身體的肌肉量。但必須留意，如果缺乏運動，單純增加蛋白質攝入量，對肌肉維持的效果其實非常有限。」

[Note 31] Devries et al (J Nutr 2018), and the Consumer Council's sentence about people with chronic disease.

「Postintervention GFR comparisons indicate that HP diets result in higher GFRs; however, when changes in GFR were compared, dietary protein had no effect. Our analysis indicates that HP intakes do not adversely influence kidney function on GFR in healthy adults.」

"In addition, the actual protein requirement varies with a person's activity level, state of health and clinical circumstances. People with a chronic disease (chronic kidney disease, for instance) or with other special medical needs should seek individual assessment and guidance from a registered dietitian and other healthcare professionals." (our translation from the Chinese original)

Chinese original:

「此外，實際的蛋白質需求量會因個人活動量、健康狀況及臨床情況而有所不同。患有慢性疾病（例如慢性腎臟病）或有其他特殊醫療需求的人士，應尋求註冊營養師及其他醫護專業人員的個別評估與指導。」

[Note 32] International Society of Sports Nutrition (ISSN) position stand on creatine, 2017: the effect figures, the dosing regimens, the safety statements, the 「no evidence that」 sentences, and the passage on kidney function with its qualification.

「In a normal diet that contains 1–2 g/day of creatine, muscle creatine stores are about 60–80% saturated. Therefore, dietary supplementation of creatine serves to increase muscle creatine and PCr by 20–40%」 「After creatine loading, performance of high intensity and/or repetitive exercise is generally increased by 10–20% depending on the magnitude of increase in muscle PCr」

「The quickest method of increasing muscle creatine stores may be to consume ~0.3 g/kg/day of creatine monohydrate for 5–7-days followed by 3–5 g/day thereafter to maintain elevated stores. Initially, ingesting smaller amounts of creatine monohydrate (e.g., 3–5 g/day) will increase muscle creatine stores over a 3–4 week period, however, the initial performance effects of this method of supplementation are less supported.」

「There is no compelling scientific evidence that the short- or long-term use of creatine monohydrate (up to 30 g/day for 5 years) has any detrimental effects on otherwise healthy individuals or among clinical populations who may benefit from creatine supplementation.」

「Thus, contrary to unsubstantiated reports, the peer-reviewed literature demonstrates that there is no evidence that: 1) creatine supplementation increases the anecdotally reported incidence of musculoskeletal injuries, dehydration, muscle cramping, gastrointestinal upset, renal dysfunction, etc.; or that 2) long-term creatine supplementation results in any clinically significant side effects among athletes during training or competition for up to 3 years. If anything, evidence reveals that athletes who take creatine during training and competition experience a lower incidence of injuries compared to athletes who do not supplement their diet with creatine.」

「While some have suggested that individuals with pre-existing renal disease consult with their physician prior to creatine supplementation in an abundance of caution, these studies and others have led researchers to conclude that there is no compelling evidence that creatine supplementation negatively affects renal function in healthy or clinical populations」

「There were no statistical differences between the control group and the creatine consumer group for plasma contents and urine excretion rates for creatinine, urea, and albumin.」 ⚠️ 它自己的結論句帶著一個範圍限定，而本文對其他來源一直都寫這一項，所以這度亦要寫：「Neither short-term, medium-term, nor long-term oral creatine supplements induce detrimental effects on the kidney of healthy individuals.」「健康人士」這個範圍是它自己劃的界。

[Note 33] Antonio et al (J Int Soc Sports Nutr 2021): creatine raising blood creatinine, and the caution addressed to clinicians.

「In skeletal muscle, both creatine and PCr are degraded non-enzymatically to creatinine, which is exported to the blood and excreted in the urine. Healthy kidneys filter creatinine, which would otherwise increase in the blood. Therefore, blood creatinine levels can be used as a proxy marker of kidney function. However, the amount of creatinine in the blood is related to muscle mass (i.e. males have higher blood creatinine than females) and both dietary creatine and creatinine intake. Both blood and urinary creatinine may be increased by ingestion of creatine supplementation and creatine containing foods, such as meat.」 「In reality, transient increases in blood or urinary creatine or creatinine due to creatine supplementation are unlikely to reflect a decrease in kidney function. Additionally, one must exercise caution when using blood creatinine and estimated creatinine clearance/glomerular filtration rate in individuals who consume high meat intake or supplement with creatine.」 「In a review of creatine supplementation studies, Persky and Rawson found no increase in serum creatinine in 12 studies, 8 studies showed an increase that remained within the normal range, and only 2 studies showed an increase above normal limits (although not different from the control group in one study).」

[Note 34] The same paper on product purity.

「other sources of creatine monohydrate that have different starting materials (e.g., sarcosinates and O-alkylisourea, sarcosinates and S-alkylisothiourea) and methods of creatine synthesis, particularly from sources produced in China, have been found to contain up to 5.4% dicyandiamide, 0.09% dihydrotriazine, 1.3% creatinine, dimethyl sulphate, thiourea, and/or higher concentrations of heavy metals like mercury and lead due to use of different chemical precursors, poorly controlled synthesis processes, and/or inadequate filtration methods」

[Note 35] The funding and interest declarations of four documents: the ISSN creatine position stand, the Morton paper and its correction of 2020, Schoenfeld's declaration, and the ISSN caffeine position stand.

「Support to prepare this manuscript was provided by the Council for Responsible Nutrition.」 「RBK is a co-founder of the International Society of Sports Nutrition (ISSN) and has received externally-funded grants from industry to conduct research on creatine… He prepared this position stand update at the request of the Council for Responsible Nutrition and ISSN.」

「Competing interests: SMP has received grant support, travel expenses, and honoraria for presentations from the US National Dairy Council. This agency has supported trials reviewed in this analysis.」

「Brad Schoenfeld declares that he served on the advisory board for Dymatize Nutrition, a manufacturer of sports supplements, at the time this paper was being written. He continues to serve on the advisory board.」

「J. A is the CEO of the ISSN. The ISSN has received grants from sports supplement companies that sell caffeine-based products.」 「N.S.G consults for and is on the scientific advisory board of Nutrigenomix, a genetic testing company.」

[Note 36] European Food Safety Authority (EFSA) caffeine topic page: 400 mg a day, 200 mg for pregnant women, 200 mg in a single dose, children and adolescents, and the situations it states for itself that it did not assess.

「Intakes up to 400mg per day (about 5.7mg/kg bw per day) consumed throughout the day do not raise safety concerns for healthy adults in the general population, except pregnant women.」

「Caffeine intakes from all sources up to 200mg per day consumed throughout the day do not raise safety concerns for the foetus.」

「Single doses of 100mg (about 1.4mg/kg bw) of caffeine may affect sleep duration and patterns in some adults, particularly when consumed close to bedtime.」

「Single doses of caffeine up to 200mg – about 3mg per kilogram of body weight (mg/kg bw) from all sources do not raise safety concerns for the general healthy adult population. The same amount of caffeine does not raise safety concerns when consumed less than two hours prior to intense physical exercise under normal environmental conditions. No studies are available in pregnant women or middle aged/elderly subjects undertaking intense physical exercise.」

「The single doses of caffeine considered to be of no concern for adults (3mg/kg bw per day) may also be applied to children, because the caffeine “clearance rate” in children and adolescents is at least that of adults, and the studies available on the acute effects of caffeine on anxiety and behaviour in children and adolescents support this level. A safety level of 3mg/kg bw per day is also proposed for habitual caffeine consumption by children and adolescents.」

(In substance: the single dose considered of no concern for adults, 3mg/kg bw per day, may also be applied to children, because the caffeine clearance rate in children and adolescents is at least that of adults and the available studies on the acute effects of caffeine on anxiety and behaviour support that level; and a safety level of 3mg/kg bw per day is also proposed for habitual consumption by children and adolescents.)

「It does not consider the possible adverse effects of caffeine:」 「in groups of the population affected by a disease or medical condition;」 「in combination with medicines and/or drugs of abuse;」 「in combination with alcohol doses which, by themselves, pose a risk to health (e.g. during pregnancy, binge drinking).」

[Note 37] All eleven positions of the ISSN caffeine position stand, in full — about doses for athletic performance and not about a safety ceiling.

「1. Supplementation with caffeine has been shown to acutely enhance various aspects of exercise performance in many but not all studies. Small to moderate benefits of caffeine use include, but are not limited to: muscular endurance, movement velocity and muscular strength, sprinting, jumping, and throwing performance, as well as a wide range of aerobic and anaerobic sport-specific actions. 2. Aerobic endurance appears to be the form of exercise with the most consistent moderate-to-large benefits from caffeine use, although the magnitude of its effects differs between individuals. 3. Caffeine has consistently been shown to improve exercise performance when consumed in doses of 3-6 mg/kg body mass. Minimal effective doses of caffeine currently remain unclear but they may be as low as 2 mg/kg body mass. Very high doses of caffeine (e.g. 9 mg/kg) are associated with a high incidence of side-effects and do not seem to be required to elicit an ergogenic effect. 4. The most commonly used timing of caffeine supplementation is 60 min pre-exercise. Optimal timing of caffeine ingestion likely depends on the source of caffeine. For example, as compared to caffeine capsules, caffeine chewing gums may require a shorter waiting time from consumption to the start of the exercise session. 5. Caffeine appears to improve physical performance in both trained and untrained individuals. 6. Inter-individual differences in sport and exercise performance as well as adverse effects on sleep or feelings of anxiety following caffeine ingestion may be attributed to genetic variation associated with caffeine metabolism, and physical and psychological response. Other factors such as habitual caffeine intake also may play a role in between-individual response variation. 7. Caffeine has been shown to be ergogenic for cognitive function, including attention and vigilance, in most individuals. 8. Caffeine may improve cognitive and physical performance in some individuals under conditions of sleep deprivation. 9. The use of caffeine in conjunction with endurance exercise in the heat and at altitude is well supported when dosages range from 3 to 6 mg/kg and 4-6 mg/kg, respectively. 10. Alternative sources of caffeine such as caffeinated chewing gum, mouth rinses, energy gels and chews have been shown to improve performance, primarily in aerobic exercise. 11. Energy drinks and pre-workout supplements containing caffeine have been demonstrated to enhance both anaerobic and aerobic performance.」

[Note 38] Hong Kong Centre for Food Safety: what it says about intake for generally healthy adults and for pregnant women, and the withdrawal symptoms after stopping.

"For generally healthy adults, provided a balanced diet is kept, the caffeine taken in from a moderate amount of coffee and tea should not cause health problems. There is at present no internationally agreed recommendation on caffeine intake for adults generally." / "However, groups more susceptible to caffeine, including children, pregnant women, breastfeeding women and individuals who react more strongly to caffeine, should pay particular attention to their caffeine intake." / "In general, pregnant and breastfeeding women should limit caffeine intake to no more than 200-300 mg a day, and children should not take in more than 2.5-5 mg per kilogram of body weight a day." (our translation from the Chinese original)

Chinese original:

「對一般健康的成年人而言，只要保持均衡飲食，適量飲用咖啡和奶茶所攝取的咖啡因，應不會產生健康問題。現時國際間對一般成年人的咖啡因攝取量並未有統一的建議。」 「然而，較容易受咖啡因影響的群組，包括兒童、孕婦、授乳婦女和個別對咖啡因有較大反應的人士應特別留意其咖啡因攝取量。」 「一般而言，孕婦和授乳婦女應限制咖啡因的攝取量於每日不超過200-300毫克，兒童則每日不應攝取超過每公斤體重2.5-5毫克的咖啡因。」

"Habitual coffee drinkers who suddenly stop will get withdrawal symptoms such as headache, fatigue, irritability and difficulty concentrating." (our translation from the Chinese original)

Chinese original:

「習慣飲用咖啡的人士如突然停止飲用，會出現脫癮症狀，例如頭痛、疲勞、易怒及難以集中。」

[Note 39] All seven positions of the ISSN beta-alanine position stand, in full.

「1) Four weeks of beta-alanine supplementation (4-6 g daily) significantly augments muscle carnosine concentrations, thereby acting as an intracellular pH buffer; 2) Beta-alanine supplementation currently appears to be safe in healthy populations at recommended doses; 3) The only reported side effect is paraesthesia (tingling), but studies indicate this can be attenuated by using divided lower doses (1.6 g) or using a sustained-release formula; 4) Daily supplementation with 4 to 6 g of beta-alanine for at least 2 to 4 weeks has been shown to improve exercise performance, with more pronounced effects in open end-point tasks/time trials lasting 1 to 4 min in duration; 5) Beta-alanine attenuates neuromuscular fatigue, particularly in older subjects, and preliminary evidence indicates that beta-alanine may improve tactical performance; 6) Combining beta-alanine with other single or multi-ingredient supplements may be advantageous when supplementation of beta-alanine is high enough (4-6 g daily) and long enough (minimum 4 weeks); 7) More research is needed to determine the effects of beta-alanine on strength, endurance performance beyond 25 min in duration, and other health-related benefits associated with carnosine.」

(In substance: 1) four weeks of beta-alanine supplementation at 4 to 6 g daily significantly raises muscle carnosine concentrations and so acts as an intracellular pH buffer; 2) at the recommended doses beta-alanine currently appears safe in healthy populations; 3) the only reported side effect is paraesthesia, tingling, which studies indicate can be attenuated by divided lower doses of 1.6 g or by a sustained-release formula; 4) daily supplementation with 4 to 6 g for at least 2 to 4 weeks has been shown to improve exercise performance, with more pronounced effects in open end-point tasks and time trials lasting up to 4 minutes; 5) it attenuates neuromuscular fatigue, particularly in older subjects, and preliminary evidence indicates it may improve tactical performance; 6) combining it with other single or multi-ingredient supplements may be advantageous where the dose is high enough, 4 to 6 g daily, and long enough, a minimum of 4 weeks; 7) more research is needed on its effects on strength, on endurance performance beyond 25 minutes, and on the other health-related benefits associated with carnosine.)

[Note 40] "Natural" anabolics and steroid precursors: the word-for-word originals of the three randomised trials.

雄烯二酮：⚠️ 先講一件這個產品實際在做的事： 「Serum estradiol concentration (mean [SEM]) was higher (P<.05) in the androstenedione group after 2 (310 [20] pmol/L), 5 (300 [30] pmol/L), and 8 (280 [20] pmol/L) weeks compared with presupplementation values (220 [20] pmol/L). The serum estrone concentration was significantly higher (P<.05) after 2 (153 [12] pmol/L) and 5 (142 [15] pmol/L) weeks of androstenedione supplementation compared with baseline (106 [11] pmol/L).」也就是說：一件賣點是「提升睪固酮」的產品，睪固酮沒有郁過，郁了的是雌激素。 然後：「Androstenedione supplementation does not increase serum testosterone concentrations or enhance skeletal muscle adaptations to resistance training in normotestosterogenic young men and may result in adverse health consequences.」另：「In the androstenedione group, the serum high-density lipoprotein cholesterol concentration was reduced after 2 weeks (1.09 [0.08] mmol/L [42 (3) mg/dL] vs 0.96 [0.08] mmol/L [37 (3) mg/dL]; P<.05) and remained low after 5 and 8 weeks of training and supplementation.」 DHEA：「These results suggest that DHEA ingestion does not enhance serum testosterone concentrations or adaptations associated with resistance training in young men.」⚠️ 長期組為 n=9 對 n=10，屬「未偵測到效果」，不等於「證明無效」。 刺蒺藜：「It was concluded that T. terrestris did not produce the large gains in strength or lean muscle mass that many manufacturers claim can be experienced within 5-28 days.」同一份摘要亦記錄了那個宣稱：「Tribulus terrestris is an herbal nutritional supplement that is promoted to produce large gains in strength and lean muscle mass in 5-28 days.」

[Note 41] The two United States Food and Drug Administration consumer updates on SARMs and on bodybuilding products, including the "What to Do" section.

「SARMs, which are chemical substances that mimic the effects of testosterone and anabolic steroids, are not FDA approved. Online vendors and social media influencers are using social media to make SARMs seem safe and effective.」 「Studies and reports show SARMs are associated with serious or life-threatening health problems, such as: Increased risk of heart attack or stroke Psychosis/hallucinations Sleep disturbances Sexual dysfunction Liver injury and acute liver failure Infertility Pregnancy miscarriage Testicular shrinkage」 「Although SARMs are often marketed as dietary supplements or “sold for research use only,” they are considered unapproved drugs. SARMs cannot be legally marketed in the U.S. as a dietary supplement or drug at this time. These products are often sold with no warnings on the labels, potentially leading consumers to believe the products are safe.」 ⚠️ 同一頁緊接住第一段之後，仲有一句限定了上面張清單的份量：「The FDA continues to receive adverse event reports associated with SARMS use. The real number of consumers experiencing adverse events is likely higher due to underreporting. Because these are not approved drugs, consumers may be reluctant to report adverse events or may not be aware that they can report adverse events that they experience. In addition, they might not know that their symptoms are being caused by the product.」 該頁自己的行動指示：「The FDA recommends consumers talk to a health care professional about the use of any products for increasing muscle mass or enhancing athletic performance.」

「In addition to liver injury, anabolic (tissue/muscle building) steroids and steroid-like substances have been associated with serious reactions such as: Severe acne; Hair loss; Altered mood; Irritability; Increased aggression; Depression; Sexual dysfunction; Testicular shrinkage. They have also been associated with life-threatening reactions such as: Kidney damage; Heart attack; Stroke; Pulmonary embolism (blood clots in the lungs); Deep vein thrombosis (blood clots that occur in veins deep in the body).」 「Some who use bodybuilding products also engage in “stacking,” which is when a person uses two or more bodybuilding products at once, including stimulants or products providing false assurances of liver protection, to enhance results or “gains.” These products should be a red-flag for consumers, especially when they are promoted by and purchased from the same dealer.」

「If you’re taking any bodybuilding products that claim to contain steroids or steroid-like substances, the FDA recommends you immediately consult your health care professional because of the potentially serious health risks associated with using them and because of dangerous withdrawal problems that can arise from quickly ceasing the use of such products.」 「The agency also recommends that you:」 「Talk to your health care professional about any bodybuilding products or ingredients you have taken, or are planning to take, particularly if you are uncertain about those ingredients.」 「Talk to your health care professional if you are experiencing symptoms possibly associated with these products, particularly nausea, weakness or fatigue, fever, abdominal pain, chest pain, shortness of breath, jaundice (yellowing of the skin or whites of the eyes), or brown or discolored urine.」

[Note 42] Geyer et al (Int J Sports Med 2004): the results for the 634 supplements, the two figures stratified by supplier, and the 66 samples for which no reliable data could be obtained.

「Out of the 634 samples analysed 94 (14.8 %) contained anabolic androgenic steroids not declared on the label ("positive supplements").」 (In substance: of the 634 samples analysed, 94, or 14.8%, contained anabolic androgenic steroids not declared on the label.)

「21.1 % of the nutritional supplements from prohormone-selling companies contained anabolic androgenic steroids, whereas 9.6 % of the supplements from companies not selling prohormones were positive.」

「We could not obtain reliable data for 66 samples (10.4 %) due to matrix effects.」

[Note 43] Drug Office of the Department of Health: the eight particulars a label must carry besides the registration number.

"Besides the registration number, the label of a registered drug must state the following general particulars: the product name; the name and amount of each active ingredient; the name and address of the manufacturer; the batch number; the expiry date; the pack size and unit of quantity; the storage conditions (including any special storage conditions, where applicable); and, for a drug on free sale (that is, one not requiring a doctor's prescription and/or not requiring sale under the direction and supervision of a registered pharmacist), its method of use, dose and frequency." (our translation from the Chinese original)

Chinese original:

「除了註冊編號，註冊藥物的標籤上須註明以下一般資料： 產品名稱； 每種有效成分的名稱和分量； 製造商的姓名/名稱和地址； 生產批號； 有效限期； 產品包裝大小及數量單位； 貯存條件 (包括特別貯存條件，如適用)； 如屬自由銷售的藥物 (即毋須按照醫生處方及/或毋須在註冊藥劑師指導及監督下銷售的藥物)，它的使用方法、服用劑量及次數）。」

#What this article does not state

None of the following could be found in the sources this article rests on, and so no sentence in it states any of them:

1. NMN and NAD+: this article has read no NMN trial, and so makes no statement about its effect. ⚠️ But it has to be said plainly: the trials exist. Searching PubMed for nicotinamide mononucleotide with the publication type randomized controlled trial (consulted 3 August 2026) returns 19 papers. "There are no trials in the world" and "this article has read no trial" are two different sentences, and only the latter can be said here. As to whether Hong Kong has any regulatory document on NMN, this article has not checked, and so will not say there is none. Not having read the evidence does not mean it has been shown not to work; nor does it mean it works.
2. Any price. This article cites no Hong Kong retail price. The circulating claim that "fish oil prices run from HK$73 to $788" is not carried here: the public part of the Consumer Council's page 〈測試熱門補充劑─28款魚油及魚肝油〉, on fish oil and cod liver oil products (consumer.org.hk/tc/article/384-3223, consulted 3 August 2026), is only a summary, and there is no price anywhere in the whole of that summary; and that test was CHOICE issue 384, October 2008 — eighteen years ago, a date the circulating version usually omits. ⚠️ That negative result has a control of its own: other Consumer Council summary pages do print prices. And for the control to be accurate it has to state as many ranges as they actually printed. The public part of the toothbrush test page in CHOICE issue 593 prints three ranges in a single sentence, reproduced here whole: 「單支裝樣本售價由每件$9.0至$69.9；多支包裝樣本每包裝內有2支至8支不等，售價則由每件$9.0至$49.5，若以每支計，售價由$3.0至$17.5不等。」 — single-stick samples at $9.0 to $69.9 each; multi-packs at $9.0 to $49.5 a pack, or $3.0 to $17.5 per stick. The perfume test page in issue 592 prints two: 「每瓶/每支售價由$129至$2,850不等」, and 「以每10毫升計算，價錢由$13至$371」. That is to say, Consumer Council summary pages do print prices; this one simply did not. ⚠️ Every range has to be given whole: the low end of one range must not be paired with the high end of another, because doing so builds a price range that does not exist on the page — the low end of the first two ranges in issue 593 is $9.0 in both, and that is where the mistake is easiest to make.
3. The circulating claim that "of 76 vitamin supplements … 9 exceeded the recommended daily upper limit for certain ingredients" is not carried here. The Consumer Council page (consumer.org.hk/tc/article/503-4557, consulted 3 August 2026) is headed 「9款建議攝入量達每日上限」 — products whose recommended intake reaches the daily upper limit — while its summary reads 「個別補充劑所建議的劑量超出每日建議攝入量」 — the recommended dose of individual supplements exceeds the recommended daily intake. The difference is between "reaches" and "exceeds", and between "the daily upper limit" and "the recommended daily intake" — two different reference values; and the circulating sentence about exceeding the upper limit does not exist on that page (what is printed there are the two sentences above). That was CHOICE issue 503, September 2018. ⚠️ The heading and the summary on the same page are inconsistent with each other — this article reports the inconsistency and does not pick an answer for it.
4. The statement attributed to the American Heart Association that it "does not recommend omega-3 for people without high cardiovascular risk" is not carried here — no American Heart Association document was found. The VITAL result (above) is stronger in any case, and is cited.
5. "Stop creatine 1 week before a laboratory test" is not carried here — no source has ever recommended it; see above.
6. "Anabolic steroids are Hospital Authority prescription drugs in Hong Kong" is not carried here — the classifying body is the Pharmacy and Poisons Board of Hong Kong under the Pharmacy and Poisons Ordinance (Chapter 138), not the Hospital Authority. The Drug Office's database of registered pharmaceutical products prints a Legal Classification and a Sale Requirement for every registered product; a search for testosterone returns 6, and opening each detail page shows that all 6 have a Sale Requirement of Prescription only Medicines and a Legal Classification of Part 1, Schedule 1 & Schedule 3 Poison (see the body). ⚠️ Those 6 were counted by opening each page and not by using the database's legal classification filter — that filter has no effect on the search results (filtering by POM and not filtering return the same 6), so it is a test that cannot fail and proves nothing. What is still not carried is which class a testosterone derivative inside an unregistered product falls into — that is not a question a registration database can answer.
7. "Verify whether a product has been tested by the Hong Kong Department of Health" is not carried here — there is no such procedure. The three real checks are above.
8. A safety ceiling for caffeine. The European Food Safety Authority (EFSA) does publish figures: 400 mg a day for healthy adults, 200 mg a day for pregnant women, 200 mg in a single dose (about 3 mg per kilogram of body weight, including within two hours of intense exercise), and 3 mg per kilogram of body weight a day for habitual intake in children and adolescents; the conditions attaching to each are in the body. ⚠️ EFSA states in terms that for pregnant women, and for middle-aged and older people undertaking intense exercise, there are no studies to go on — that is unknown, and this article will not write it as safe. The eleven positions of the ISSN statement are about doses for athletic performance and set no safety ceiling, and the two are not to be run together. The Hong Kong Centre for Food Safety's figures are in the body — they differ from EFSA's, and both points of difference fall on pregnant women and on children. What is still not carried is whether the Centre for Food Safety has set a daily figure for generally healthy adults — that page states in terms that there is no internationally agreed recommendation, and prints no figure for adults.
9. The text of the Cochrane reviews on vitamin C and on zinc. This article has not obtained the full text of either review, and so does not quote them word for word but only reports them by attribution, and will make no statement about whether they have Chinese versions. ⚠️ Tried again on 9 August 2026, cochranelibrary.com returned an HTTP 302 redirect and a 0-byte body for the full text path of CD014914 — that is, still not obtainable, but the manner of not obtaining it today is not the one recorded on the day of retrieval; this article states only "not obtained", which is within its own scope, and passes no judgment on the current state of that site. On vitamin C and colds, this article uses the Hong Kong Department of Health's own Chinese page instead.
10. Intranasal zinc and loss of smell. The relevant regulatory document does exist: on 16 June 2009 the United States Food and Drug Administration (FDA) issued a warning letter to Matrixx Initiatives, Inc. (Zicam LLC) about precisely intranasal zinc and loss of smell. The original: 「FDA has received more than 130 reports of anosmia (loss of sense of smell, which in some cases can be long-lasting or permanent), associated with use of these products; some individuals also report loss of sense of taste.」 ⚠️ The sentence immediately after it is the one that gives the 130 its meaning, and this article reproduces it too: 「By comparison, FDA has received few reports of anosmia associated with other widely-used intranasal products for treatment of the common cold that are marketed subject to approved NDAs or according to an OTC drug monograph.」 Without that sentence the 130 reports are a bare number; with it, they are a comparison — the reports received for comparable products were few. The letter also records: 「the agency is aware that Matrixx appears to have more than 800 reports related to loss of sense of smell associated with Zicam Cold Remedy intranasal products.」 ⚠️ Two bounds have to be stated. First, that letter is about three named intranasal homeopathic zinc products — a nasal gel and nasal swabs — not about oral zinc supplements, and is a different matter from the Cochrane review above. Second, that letter is no longer on the FDA's live website (the original path now returns HTTP 404); what is cited here is the Internet Archive's capture of that fda.gov page (a snapshot of 14 January 2012), the letter itself being dated 16 June 2009. A regulatory document withdrawn from a live website is not a document that does not exist; but neither can it be treated as the FDA's current position today.
11. Protein and bone health. The popular claim that "a long-term excess (3 g/kg or more) may be bad for bone health" is not carried here — no relevant source could be found.
12. "In stage 3 or worse chronic kidney disease, excess protein accelerates the decline in kidney function" is not carried here — the analysis cited expressly excluded people with kidney disease.
13. "Body weight can rise by 1 to 2 kg in the 2 to 4 weeks after first using creatine" is not carried here — no weight figure could be found.
14. The "final" content and grades of the updated USPSTF fracture recommendation. The one being updated is a draft and is not final; this article carries the draft grades and dates it prints for itself (see the body), but will make no statement about what it will finally become. The 2018 one remains the current final recommendation.
15. This article gives no overall grade to any supplement, and comments on no brand.

#Sources

• Drug Office of the Department of Health, General Knowledge on Registered Medicines (the page self-dated August 2024; bilingual), https://www.drugoffice.gov.hk/eps/do/tc/consumer/news_informations/knowledge_on_medicines/general_knowledge_on_medicine_registration.html (the English version at the same path under /en/), retrieved 2 August 2026 (the sentences added to the body re-checked on 3 August 2026) — the statutory definition of a "pharmaceutical product"; the requirements as to registration, offer for sale, distribution and possession; the registration requirements; the HK-XXXXX registration number; the eight general particulars a label must state; and that page's guidance to the registered pharmaceutical products search database.
• Drug Office of the Department of Health, Slimming Products with Undeclared Western Drug Ingredients, https://www.drugoffice.gov.hk/eps/specMedsNews/slimming/tc/consumer (English version at /en/consumer), retrieved 2 August 2026 — that the list exists, is searchable and is bilingual; 845 dated records, 1998-02-19 to 2026-03-19, 81 marked as Hong Kong (counted on that page; the page publishes no total).
• Department of Health press release, 23 May 2025 (Chinese P2025052300818, English P2025052300825), https://www.info.gov.hk/gia/general/202505/23/P2025052300818.htm — the slimming product bought on a social media platform containing sibutramine and furosemide; sibutramine prohibited from use and sale since November 2010; the penalties.
• Department of Health press release, 29 January 2026 (Chinese P2026012900612, English P2026012900608), https://www.info.gov.hk/gia/general/202601/29/P2026012900612.htm, retrieved 7 August 2026 — the 「KRN+PM」 slimming product containing hydrochlorothiazide and fluoxetine; the risks of buying controlled drugs online (including the 「冷鍵」 as printed in that release); the penalties paragraph (including the sentence that Part 1 poisons may be sold only in registered pharmacy premises); that the safety, quality and efficacy of unregistered pharmaceutical products are not guaranteed; and that release's own instruction to stop taking it (「已購買上述產品的市民應立即停止服用……應尋求醫護人員的意見」 — worded differently from the corresponding paragraph of the release of 23 May 2025).
• Drug Office of the Department of Health, Vitamins (the page self-dated December 2024; bilingual), https://www.drugoffice.gov.hk/eps/do/tc/consumer/news_informations/knowledge_on_medicines/vitamins.html, retrieved 2 August 2026 (the sentences added to the body re-checked on 3 August 2026) — the three misconceptions (excess vitamin A and D, vitamin C with colds and kidney stones, and topical vitamin E); 「不應服用過量…尤其不可以讓兒童」; the sentence of exceptions for pregnant women, breastfeeding women and smokers needing extra supplementation; peripheral neuropathy from vitamin B6 and its instruction to stop; and all seven items of the checklist on buying vitamins (the six thresholds (a) to (f) for prescription vitamin products being the sixth of them, and the seventh being to consult your doctor before taking any vitamin long term).
• Drug Office of the Department of Health, Drug Interactions with Foods and Beverages (the page self-dated February 2020; bilingual), https://www.drugoffice.gov.hk/eps/do/tc/consumer/news_informations/knowledge_on_medicines/food_drug_interaction.html, retrieved 2 August 2026 — red yeast rice, monacolin K and lovastatin; that statins are prescription drugs; the interactions between calcium-containing foods and drugs; and the list of seven examples.
• Consumer Council CHOICE issue 594 (April 2026), 〈蛋白粉人人合適？坊間迷思逐一拆解〉, https://www.consumer.org.hk/tc/article/594-protein-powder, retrieved 2 August 2026 — the composition of protein powder; the four recommended protein intakes; 「不會讓肌肉『長得更快』」; that people with chronic kidney disease should seek an individual assessment; sarcopenia in older people and resistance training; and the DIAAS table and the high-protein food table (in the accompanying PDF data table).
• Manson JE, et al. N Engl J Med 2019;380(1):33-44 (VITAL vitamin D; PMID 30415629; DOI 10.1056/NEJMoa1809944) — 25,871 people, median follow-up 5.3 years; no effect on either cancer or major cardiovascular events.
• Manson JE, et al. N Engl J Med 2019;380(1):23-32 (VITAL marine n-3; PMID 30415637; DOI 10.1056/NEJMoa1811403) — no effect on cardiovascular disease or cancer; the secondary endpoint of total myocardial infarction at 0.72.
• LeBoff MS, et al. N Engl J Med 2022;387(4):299-309 (PMID 35939577; DOI 10.1056/NEJMoa2202106) — no effect on fracture; 769/12,927 against 782/12,944; the scope limitation of the conclusion; and the abstract's statement that treatment effects did not differ by baseline characteristics, including the serum 25-hydroxyvitamin D level (quoted in the body).
• Sesso HD, et al. Am J Clin Nutr 2022;115(6):1501-1510 (COSMOS multivitamin; PMID 35294969) — 21,442 people, median follow-up 3.6 years; no significant effect on cancer, cardiovascular events or all-cause mortality; lung cancer at 0.62 and colorectal cancer at 1.30.
• Jackson RD, et al. N Engl J Med 2006;354(7):669-83 (WHI; PMID 16481635) — 36,282 people; intention-to-treat hip fracture 0.88 (0.72–1.08); kidney stones 1.17 (1.02–1.34); 0.71 (0.52–0.97) with non-adherence censored.
• Sanders KM, et al. JAMA 2010;303(18):1815-22 (PMID 20460620) — 500,000 IU once a year; increased falls and fractures.
• Bischoff-Ferrari HA, et al. JAMA Intern Med 2016;176(2):175-83 (PMID 26747333) — high monthly doses; the incidence of falls.
• The Alpha-Tocopherol, Beta Carotene Cancer Prevention Study Group. N Engl J Med 1994;330(15):1029-35 (ATBC; PMID 8127329) — 29,133 male smokers; lung cancer incidence 18% higher; total mortality 8% higher.
• Omenn GS, et al. N Engl J Med 1996;334(18):1150-5 (CARET; PMID 8602180) — 18,314 people; relative risk of lung cancer 1.28; the trial stopped 21 months early.
• Klein EA, et al. JAMA 2011;306(14):1549-56 (SELECT; PMID 21990298) — hazard ratio for prostate cancer in the vitamin E arm 1.17 (99% CI 1.004–1.36).
• Lippman SM, et al. JAMA 2009;301(1):39-51 (the first SELECT report; PMID 19066370) — vitamin E 1.13 (99% CI 0.95–1.35), concluding that it did not prevent prostate cancer.
• Miller ER 3rd, et al. Ann Intern Med 2005;142(1):37-46 (PMID 15537682) — 19 trials and 135,967 people; a risk difference for all-cause mortality with high-dose vitamin E of 39 per 10,000 people; and the authors' own statement of the limits on generalisation.
• Schürks M, et al. BMJ 2010;341:c5702 (PMID 21051774; DOI 10.1136/bmj.c5702) — 9 trials and 118,765 people; haemorrhagic stroke 1.22 and ischaemic stroke 0.90; one additional haemorrhagic stroke per 1,250 people and one ischaemic stroke prevented per 476.
• US Preventive Services Task Force, the recommendation on vitamin, mineral and multivitamin supplementation to prevent cardiovascular disease and cancer (document dated 21 June 2022; JAMA 2022;327(23):2326-2333; PMID 35727271), https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/vitamin-supplementation-to-prevent-cvd-and-cancer-preventive-medication, retrieved 2 August 2026 — the three-row recommendation summary table (grade D, grade I, grade I); the scope and exclusions; the folic acid recommendation; and the complete text of the harms section.
• US Preventive Services Task Force, the recommendation on vitamin D, calcium or combined supplementation to prevent fractures (JAMA 2018;319(15):1592-1599; PMID 29677309), https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/vitamin-d-calcium-or-combined-supplementation-for-the-primary-prevention-of-fractures-in-adults-preventive-medication, retrieved 7 August 2026 — the three grades; the four exclusions under "Patient Population Under Consideration"; the "Response to Public Comment"; the "Potential Harms" (1 urinary tract stone per 273 women); and the page's own statement that the topic is being updated.
• US Preventive Services Task Force, the update in progress page for the same topic (the page self-reporting LAST UPDATED: Dec 17, 2024), https://www.uspreventiveservicestaskforce.org/uspstf/draft-update-summary/vitamin-d-calcium-combined-supplementation-primary-prevention-falls-fractures-communitydwelling-adults, retrieved 7 August 2026 and re-read and checked on 9 August 2026 (40,474 bytes) — the title of the document being updated (with Falls added to its scope); the update page's self-reported date LAST UPDATED: Dec 17, 2024; and the sentence 「Public Comments are Closed for this topic.」 printed on this page.
• US Preventive Services Task Force, the draft recommendation statement (not final): Vitamin D, Calcium, or Combined Supplementation for the Primary Prevention of Falls and Fractures in Community-Dwelling Adults, https://www.uspreventiveservicestaskforce.org/uspstf/draft-recommendation/vitamin-d-calcium-combined-supplementation-primary-prevention-falls-fractures-communitydwelling-adults, retrieved 7 August 2026 — the two-row draft recommendation summary and its draft grade D; the draft's "Patient Population Under Consideration"; the "Definitions" section (the definition of supplementation; the recommended daily allowances for vitamin D and calcium of 600–800 IU and 1,000–1,200 mg, meaning all dietary sources); and 「When final, this draft recommendation will replace the 2018 USPSTF recommendation…」. ⚠️ The sentence 「Public Comments are Closed for this topic.」 is not on this page (re-read on 9 August 2026, 87,711 bytes; the same reading tool found that sentence on the topic's update page) — see the previous item. A draft grade is not a current grade.
• NIH Office of Dietary Supplements, Vitamin D — Health Professional Fact Sheet (the overview self-dated Updated June 27, 2025), https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/, retrieved 2 August 2026 — the manifestations of toxicity; the complete UL table; the Food and Nutrition Board's statement that effects are possible below the UL; the WHI kidney stone passage (against a background of about 2,100 mg of total calcium intake a day) and the sentence immediately after it noting that other, shorter trials saw hypercalcaemia and hypercalciuria but not kidney stones (quoted in the body); and the four drug interactions (expressly examples).
• NIH Office of Dietary Supplements, Vitamin K — Health Professional Fact Sheet (Updated March 29, 2021), https://ods.od.nih.gov/factsheets/VitaminK-HealthProfessional/, retrieved 2 August 2026 — the four drug interactions (expressly examples); and that warfarin users should keep their intake consistent.
• NIH Office of Dietary Supplements, Vitamin E — Health Professional Fact Sheet (Updated March 26, 2021), https://ods.od.nih.gov/factsheets/VitaminE-HealthProfessional/, retrieved 2 August 2026 — the complete UL table; the IU to milligram conversion; and the three drug interactions (expressly examples).
• NIH Office of Dietary Supplements, Vitamin A and Carotenoids — Health Professional Fact Sheet (Updated March 10, 2025), https://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/, retrieved 2 August 2026 — vitamin A toxicity; the 10,000 IU advice for pregnant women; the complete UL table and its note; that beta-carotene has no UL and the advice about it to the general population; and the two drug interactions (expressly examples).
• National Center for Complementary and Integrative Health, St. John's Wort (the page self-dated Last Updated: May 2025), https://www.nccih.nih.gov/health/st-johns-wort, retrieved 2 August 2026 — the complete text of the safety section and the list of nine classes of drug (expressly examples).
• Morton RW, et al. Br J Sports Med 2018;52(6):376-384 (PMID 28698222; DOI 10.1136/bjsports-2017-097608; correction 2020, PMID 32943392) — 49 studies and 1,863 people; the ceiling of 1.62 g/kg/day; the effect sizes; and the dairy funding declaration and the advisory board declaration in the correction.
• Devries MC, et al. J Nutr 2018;148(11):1760-1775 (PMID 30383278; DOI 10.1093/jn/nxy197) — 28 trials and 1,358 people; high protein and glomerular filtration rate in healthy adults; the two results in the abstract running in different directions; and the selection bias limitation.
• Kreider RB, et al. J Int Soc Sports Nutr 2017;14:18 (PMID 28615996; DOI 10.1186/s12970-017-0173-z) — the creatine effect figures, the dosing regimens, the 「no evidence that」 passages, the kidney function qualification, and the Council for Responsible Nutrition funding and interest declaration.
• Antonio J, et al. J Int Soc Sports Nutr 2021;18(1):13 (PMID 33557850) — the creatinine measurement artefact and its mechanism; the counts of 12, 8 and 2 studies by Persky and Rawson; and product purity and impurities.
• Poortmans JR, Francaux M. Med Sci Sports Exerc 1999;31(8):1108-10 (PMID 10449011) — no statistical difference in kidney function measures between creatine users and controls (the abstract giving no sample size).
• Guest NS, et al. J Int Soc Sports Nutr 2021;18(1):1 (PMID 33388079) — the full text of the eleven caffeine positions; and the interest declaration.
• Drug Office of the Department of Health, Search Drug Database (check three; the advanced search has fields for the Hong Kong registration number, product name, active ingredient and certificate holder; the results and detail pages are available in English only; records carry a Legal Classification and a Sale Requirement and no indications; the database self-reporting Last Updated: 31-Jul-2026): https://www.drugoffice.gov.hk/eps/do/tc/consumer/search_drug_database.html (the English version at the same path; there is also a search_drug_database2.html version, the one to which the General Knowledge on Registered Medicines page points) (retrieved 3 August 2026) — the legal classification and sale requirement of the 6 registered testosterone products; and the ANDROGEL HK-57974 detail page.
• US Food and Drug Administration, Warning Letter to Matrixx Initiatives, Inc. AKA Zicam LLC, the letter dated 16 June 2009 — intranasal zinc products and loss of smell (more than 130 direct reports; the comparison sentence immediately following, 「By comparison, FDA has received few reports…」; and the more than 800 reports held by Matrixx). ⚠️ That letter is no longer on the FDA's live website (the original path fda.gov/ICECI/EnforcementActions/WarningLetters/ucm166909.htm now returns HTTP 404); what is cited here is the Internet Archive's snapshot of that page (14 January 2012): https://web.archive.org/web/20120114144732/http://www.fda.gov/ICECI/EnforcementActions/WarningLetters/ucm166909.htm (retrieved 3 August 2026)
• Consumer Council CHOICE issue 384 (October 2008), 〈測試熱門補充劑─28款魚油及魚肝油〉, https://www.consumer.org.hk/tc/article/384-3223, retrieved 3 August 2026 — the public part is a summary only, and the whole of that summary carries no price (see item 2 of "What this article does not state").
• Consumer Council CHOICE issue 503 (September 2018), 〈76款維他命補充劑大檢閱 9款建議攝入量達每日上限〉, https://www.consumer.org.hk/tc/article/503-4557, retrieved 7 August 2026 — the inconsistency between the heading's "reaches the daily upper limit" and the summary's "exceeds the recommended daily intake" (see item 3).
• Consumer Council CHOICE issue 593 (March 2026), the toothbrush test, https://www.consumer.org.hk/tc/article/593-toothbrush, retrieved 7 August 2026 and re-read and checked on 9 August 2026 — the summary page printing three ranges in a single sentence (single sticks at $9.0–$69.9; multi-packs at $9.0–$49.5 a pack; $3.0–$17.5 per stick); used as the control for "Consumer Council summary pages do print prices" (see item 2 of "What this article does not state").
• Consumer Council CHOICE issue 592 (February 2026), the perfume test, https://www.consumer.org.hk/tc/article/592-perfume, retrieved 7 August 2026 — the summary page printing prices (per bottle $129–$2,850; per 10 ml $13–$371); the same control.
• Centre for Food Safety and Consumer Council, on the caffeine content of coffee and tea prepared in local eateries (in Chinese), https://www.cfs.gov.hk/tc_chi/programme/programme_rafs/programme_rafs_fci_01_04.html, consulted 7 August 2026 — that there is no internationally agreed recommendation for generally healthy adults; no more than 200-300 mg a day for pregnant and breastfeeding women; no more than 2.5-5 mg per kilogram of body weight a day for children; and the per-cup figures measured in that study's 80 samples (ordinary coffee averaging 200 mg, range 110-380 mg; Hong Kong style milk tea averaging 170 mg, range 73-220 mg; Taiwanese style milk tea averaging 130 mg, range 100-160 mg).
• Centre for Food Safety, 〈咖啡：大眾日常的早餐飲品〉, on coffee as an everyday breakfast drink (in Chinese), https://www.cfs.gov.hk/tc_chi/multimedia/multimedia_pub/multimedia_pub_fsf_153_01.html, consulted 7 August 2026 — the withdrawal symptoms after stopping suddenly; and the reference figure it cites of about 90 to 200 mg of caffeine a cup (not the same as that study's own measured figures in the previous item, this article setting the two side by side without adjudicating).
• European Food Safety Authority (EFSA) caffeine topic page: https://www.efsa.europa.eu/en/topics/topic/caffeine (consulted 3 August 2026) — the three items for adults in the "How much caffeine is it safe to consume?" section (a single dose of 200 mg, about 3 mg/kg, including within two hours of exercise, with no studies for pregnant women or for middle-aged and older people exercising intensely; a single dose of 100 mg and sleep; and 400 mg a day except for pregnant women), 200 mg a day for pregnancy and breastfeeding, and 3 mg per kilogram of body weight a day for children and adolescents; and the three unassessed situations listed in the "What does EFSA's assessment cover?" section (diseased populations, combined with medication or drugs of abuse, and combined with amounts of alcohol constituting a health risk).
• Trexler ET, et al. J Int Soc Sports Nutr 2015;12:30 (PMID 26175657) — the full text of the seven beta-alanine conclusions.
• King DS, et al. JAMA 1999;281(21):2020-8 (PMID 10359391) — androstenedione; no change in testosterone; HDL fell.
• Brown GA, et al. J Appl Physiol (1985) 1999;87(6):2274-83 (PMID 10601178) — DHEA; no difference in testosterone or in training adaptation.
• Rogerson S, et al. J Strength Cond Res 2007;21(2):348-53 (PMID 17530942) — Tribulus terrestris; no between-group difference in strength or lean mass.
• US Food and Drug Administration, FDA Warns of Use of Selective Androgen Receptor Modulators (SARMs) Among Teens, Young Adults (the page self-dated Content current as of: 04/26/2023), https://www.fda.gov/consumers/consumer-updates/fda-warns-use-selective-androgen-receptor-modulators-sarms-among-teens-young-adults, retrieved 2 August 2026 — that SARMs are not approved; and the illustrative list of health problems.
• US Food and Drug Administration, Caution: Bodybuilding Products Can Be Risky (the page self-dated Content current as of: 09/20/2024), https://www.fda.gov/consumers/consumer-updates/caution-bodybuilding-products-can-be-risky, retrieved 7 August 2026 — the illustrative list of reactions associated with anabolic steroids; the body passage on "stacking"; the governing first sentence of the "What to Do" section (immediately consult … dangerous withdrawal problems), its 「The agency also recommends that you:」 lead-in and the two items following; and the passage on dietary supplements not being reviewed before marketing.
• Geyer H, et al. Int J Sports Med 2004;25(2):124-9 (PMID 14986195) — 94 of 634 samples (14.8%) containing undeclared anabolic androgenic steroids; bought in 2000–2001 in 13 countries.
• Geyer H, et al. J Mass Spectrom 2008;43(7):892-902 (PMID 18563865) — products intentionally spiked with anabolic steroids detected from 2002 onwards.
• Nault D, et al. Cochrane Database Syst Rev 2024;5(5):CD014914 (PMID 38719213) — zinc and the common cold (reported here by attribution only and not quoted word for word; the reason is at item 9 of "What this article does not state").

#Further reading

• On this platform: Weight-loss drugs

This article was compiled by the editorial team from official and academic sources, with every clinical statement attributed; it is health information and not medical advice. Whether to take any supplement, and at what dose, should be discussed with a doctor or pharmacist first, particularly by anyone on medication, with a long-term condition, pregnant or planning a pregnancy.