Milk Thistle for Liver Protection
Silymarin is widely used in liver disease but trials show inconsistent effects on clinically meaningful outcomes.
Overview
Verdict
How It Works
Dosing & Protocol
Typical dose
- Recommended dose
- 140 mg silymarin two to three times daily (420 mg/day total), standardised to 70-80% silymarin, taken with food
- Expected timeframe
- 3-6 months
Protocol
- form
- Milk thistle extract standardised to 70-80% silymarin. Silybin-phosphatidylcholine complexes have better bioavailability, since silymarin is poorly absorbed
- duration
- 3-6 months, with liver enzymes checked before and after
- co factor
- Take with food to improve absorption of this poorly soluble compound. Evidence is genuinely mixed. Silymarin has plausible and well-described mechanisms - it stabilises hepatocyte membranes, scavenges free radicals, raises glutathione, and inhibits the binding of some toxins to hepatocyte receptors. In non-alcoholic fatty liver disease, meta-analyses of randomised trials show modest reductions in ALT and AST, and some improvement in fibrosis markers. In alcoholic and viral hepatitis, Cochrane reviews found no convincing effect on mortality, liver histology or complications. The one clear-cut use is intravenous silibinin for Amanita phalloides mushroom poisoning, which is a hospital treatment and not related to oral supplements.
- titration
- Up to 420 mg/day in three divided doses; trials in liver disease have used up to 600-800 mg/day
- starting dose
- 140 mg silymarin twice daily with food
Evidence
What the studies say
Milk thistle for alcoholic and/or hepatitis B or C liver diseases: a systematic Cochrane Hepato-Biliary Group review with meta-analyses of randomized clinical trials
Rambaldi A, Jacobs BP, Gluud C
Milk thistle did not significantly influence mortality, complications or liver histology in chronic liver disease.
Silymarin in non-alcoholic fatty liver disease: a systematic review and meta-analysis of randomized controlled trials
Zhong S, Fan Y, Yan Q
Silymarin significantly reduced serum ALT and AST in patients with non-alcoholic fatty liver disease.
Silibinin as a treatment for Amanita phalloides poisoning: a systematic review of clinical experience
Mengs U, Pohl RT, Mitchell T
Early intravenous silibinin was associated with low mortality in amatoxin mushroom poisoning.
Safety
Caveats
Milk thistle does not protect the liver from ongoing injury, and treating it as licence to continue drinking or to take hepatotoxic substances is the main harm associated with it. For fatty liver disease, weight loss of 7-10% is the intervention that reverses steatohepatitis, and no supplement matches it. Alcohol-related liver disease requires stopping alcohol; viral hepatitis has curative or highly effective antiviral treatment that should not be delayed. Jaundice, abdominal swelling, confusion, vomiting blood or black stools need urgent medical attention. Safety: milk thistle is generally well tolerated, with mild gastrointestinal upset the commonest effect and occasional allergic reactions, particularly in people allergic to plants in the Asteraceae family such as ragweed, daisies and chrysanthemums. Silymarin may inhibit CYP2C9 and affect P-glycoprotein, so caution is warranted with warfarin, phenytoin, statins and some chemotherapy agents - check with a pharmacist if you take narrow-therapeutic-index drugs. It may lower blood glucose, so monitor if you take diabetes medication. Because of weak oestrogenic activity, use caution in hormone-sensitive conditions. Safety in pregnancy and breastfeeding is not established, though it has been used traditionally as a galactagogue - discuss with your clinician.
Less likely to help if
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Individual results may vary. The statements on this website have not been evaluated by the Food and Drug Administration. Products and information are not intended to diagnose, treat, cure, or prevent any disease.