Milk thistle
Content by: OpenSupplement Editorial Team | Medical review: pending | Last updated: April 13, 2026
TL;DR
Traditional liver herb containing the active complex Silymarin
High evidence for protecting the liver from toxins and alcohol
Moderate evidence for helping with Fatty Liver (NAFLD) and Hepatitis
Acts as a powerful antioxidant and 'membrane stabilizer' in liver cells
Extremely safe; very low toxicity
Cost: ~$10-18/month
Best for: Liver detox, hangover prevention, NAFLD support
What it is
Milk thistle is the world's most popular liver supplement. The active component, Silymarin, is actually a group of several molecules, with Silybin being the most potent. It works by blocking toxins from entering liver cells and by stimulating the liver to produce more protein to repair itself.
What the research says
Milk thistle is a legitimate 'hepatoprotective' agent. Evidence. A review of clinical trials showed that Silymarin significantly reduced liver enzymes and improved survival in patients with alcoholic liver disease. Fatty Liver. It is a core recommendation for NAFLD, where it helps reduce the 'oxidative stress' that causes fat to turn into permanent scar tissue. [1][2][3]
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Milk thistle on Amazon
Safety
Extremely safe. It has been used for 2,000 years with almost no reports of serious toxicity. It can have a mild laxative effect at very high doses.
Interactions
- Many Drugs: Silymarin may inhibit CYP3A4 and CYP2C9 enzymes, potentially increasing the levels of drugs like Warfarin, Statins, or Diazepam (though clinical significance is usually low).
Dosing
Standard Dose: 420-600 mg daily of standardized extract (70-80% Silymarin). Form: Silybin Phytosome (bound to fats) is 5-10x better absorbed than standard powder.
Cost
Affordable. $10-18 per month.
The bottom line
Milk thistle is the gold standard for liver support. If your liver is under stress from diet, alcohol, or medications, this is the first supplement you should reach for.
References
- Abenavoli L, Capasso R, Milic N, Capasso F. Milk thistle in liver diseases: past, present, future. Phytother Res. 2010;24(10):1423-1432.
- Gillessen A, Schmidt HH. Silymarin as supportive treatment in liver diseases: A narrative review. Adv Ther. 2020;37(4):1279-1301.
- Cacciapuoti F, Scognamiglio A, Palumbo R, Forte R, Cacciapuoti F. Silymarin in non alcoholic fatty liver disease. World J Hepatol. 2013;5(3):109-113.
Sources for this page include published meta-analyses, systematic reviews, and NIH dietary supplement fact sheets. All claims reflect the evidence as of early 2026.
This is not medical advice. Consult your healthcare provider before starting any supplement, especially if you take medications.