The Liver Support Supplement Guide

NIDDK lists the liver as one of the three solid organs of the digestive system and gives its digestive job in a line: it makes bile, which breaks down fats and travels the bile ducts to the small intestine.

Nothing in that description resembles a filter that clogs. NCCIH on detoxes and cleanses is the plainest source on the word: the studies are few and of low quality, and a 2015 review found no compelling research supporting detox regimes for eliminating toxins from the body. The FDA and the FTC have acted against detox sellers over hidden ingredients and false disease claims. So the question a label answers is what each ingredient is, and how much.

Milk thistle is Silybum marianum, and silymarin is the mixture of flavonolignans extracted from its seed. NCCIH calls silymarin the plant’s main active constituent and states its finding plainly: there is not enough high-quality evidence for definite conclusions about milk thistle’s effects in people.

The best dose anchor in the category is the SyNCH trial: 420 mg or 700 mg of silymarin three times a day, 1,260 or 2,100 mg daily, for 24 weeks. Neither dose beat placebo on ALT — the liver enzyme a blood panel measures. The Cochrane review pooled 18 trials and 1,088 patients and found no significant effect on mortality, complications or liver histology.

Both were run in people with diagnosed liver disease, which is not who buys a supplement. What they establish is the scale: the trials that found nothing were using more than a gram a day. LiverTox puts the retail range at 250 to 750 mg two or three times daily, and scores milk thistle E, its lowest.

Berberine is an alkaloid drawn from barberry, goldenseal and other plants. It has the largest modern trial literature on a typical liver panel, and almost none of it is about the liver: a 2021 meta-analysis of 46 randomised trials found reductions in HbA1c, fasting glucose and post-meal glucose in people with type 2 diabetes. That is a glucose literature — in people with a diagnosis.

The interaction is the part worth carrying away. Guo 2012 gave healthy men 900 mg a day for two weeks: CYP2D6, CYP2C9 and CYP3A4 activity all fell, midazolam exposure rose 40 per cent, and the dextromethorphan ratio rose ninefold. Those three enzymes clear a long list of prescriptions between them, and the authors conclude that drug interactions should be considered.

NCCIH adds three things a label will not. Effects in the reviewed studies appeared mainly above a gram a day for more than eight weeks, and many of those studies carried a high risk of bias. Cyclosporine is named as an interaction. And berberine has been linked to a harmful buildup of bilirubin in infants, is likely unsafe for them, and may be unsafe in pregnancy or while breastfeeding. LiverTox puts the usual herbal-product dose at 250 to 500 mg two or three times daily and scores it E.

Molybdenum is an essential trace mineral and a cofactor for sulfite oxidase and two other enzymes, the closest thing to a mechanism story on a liver panel. The NIH Office of Dietary Supplements publishes both numbers: a recommended dietary allowance of 45 micrograms a day for adults, and a tolerable upper intake level of 2,000 micrograms.

So this is the only ingredient here with a published ceiling, and the only one where a label amount could be checked against anything. Deficiency is also essentially unknown in healthy people eating ordinary food — legumes are rich in it — so a supplemental amount fills no common gap. ODS states that molybdenum has no known, clinically relevant interactions with medications.

Drinking green tea is not the issue. LiverTox is explicit that tea drinking has not been associated with liver injury. The concern is the concentrated extract in capsule form, and specifically its catechins, mainly EGCG. LiverTox scores green tea A, its highest, meaning a well-established cause of clinically apparent liver injury: more than 100 published cases, onset usually one to six months in, most resolving one to two months after stopping, and fatal acute liver failure described.

It is also rare, and that belongs in the same paragraph. LiverTox says the rate of symptomatic injury is undoubtedly low against the wide scale on which these products are used, and susceptibility looks individual rather than dose-driven. NCCIH puts the immune-gene variant that makes people markedly more prone at 5 to 15 per cent of Americans, and names two interactions besides — the extract lowers atorvastatin blood levels and interacts with raloxifene.

Three numbers are worth holding. The Minnesota Green Tea Trial gave 1,075 postmenopausal women 843 mg of EGCG a day for a year: ALT rose above normal in 6.7 per cent against 0.7 on placebo. EFSA put the transaminase signal at 800 mg a day and above, against roughly 90 to 300 mg from an infusion. And the US Pharmacopeia found published injury cases from about 140 mg a day upwards, which is why a small amount is not by itself a safety argument.

Every figure above is the amount the cited study used. None can be set against any particular bottle unless that bottle prints one.

A phrase such as “supports liver detoxification” is a structure/function claim. The FDA’s page on those claims sets out what that means: the manufacturer notifies the agency within 30 days of first using the claim rather than applying for permission, nobody reviews it beforehand, and the label must carry the statement that the FDA has not evaluated it.

The reason is in the same sentence as the rest of it. A supplement is not intended to diagnose, treat, cure or prevent any disease, in the FDA’s words, because only a drug can legally make such a claim. A page describing what a capsule does for cirrhosis has stopped describing a supplement.