How we rate
“Strong” = several concordant meta-analyses or systematic reviews. “Moderate” = one synthesis, or several controlled trials. “Limited” = early trials only. The rating is about the quality of the studies, not about how useful the supplement is.
Milk thistle (silymarin)
A plant from which silymarin is extracted, studied in liver disease patients and diabetics. It slightly lowers transaminases, but major reviews find no effect on mortality or liver condition.
Benefits
- Liver steatosis (NAFLD/NASH): lower transaminases (ALT, AST) and less fat in the liver, in a meta-analysis of 26 trials and 2,375 patients
- Type 2 diabetes: lower fasting blood glucose and HbA1c (5 trials, 270 patients); at 200 mg three times a day for 4 months, a drop in HbA1c, blood glucose, LDL and triglycerides in 51 patients
- Under anti-tuberculosis treatment: 3.7% liver lesions under silymarin vs 32.1% under placebo (55 patients); fewer lesions at 4 weeks in a meta-analysis of 5 trials (1,198 patients)
- Cirrhosis: 4-year survival of 58% vs 39% under placebo at 140 mg three times a day (170 patients), especially in alcoholic cirrhosis — a result that the subsequent trial (200 patients) does not find
- Acute hepatitis: jaundice and dark urine disappeared faster at 140 mg three times a day for 4 weeks (105 patients), without a change in transaminases
- NASH: less liver fibrosis after 48 weeks at 700 mg three times a day (99 patients), with no effect on the disease activity score
Precautions
If you have a liver disease, silymarin does not replace medical follow-up: talk to your doctor about it. In trials, it did not cause more adverse effects than the placebo, and human studies do not show notable drug interactions at concentrations reached in the blood (the level of indinavir, an HIV treatment, did not budge). Also worth knowing: the Cochrane review (13 trials, 915 patients) finds no effect, in good quality trials, on mortality, complications or liver condition on biopsy; another meta-analysis of 14 trials sees only a slight drop in ALT, with no clinical significance. In alcoholic cirrhosis, the large trial of 200 patients does not find the survival gain of the first. In 1,049 patients with advanced hepatitis C, silymarin changed nothing regarding clinical evolution over 8.65 years of follow-up. Meta-analyses on steatosis and diabetes rely on trials that are often of low quality.
Recommended dosage
140 mg of silymarin three times a day in cirrhosis and acute hepatitis, 200 mg three times a day in diabetes; up to 700 mg three times a day in trials on NASH and hepatitis C.
How to take it
- For whom: all studies in this profile concern patients (liver diseases, type 2 diabetes, tuberculosis under treatment); none on healthy individuals.
- Dose: 140 mg of silymarin three times a day in cirrhosis (170 patients) and acute hepatitis (105 patients); 200 mg three times a day in type 2 diabetes (51 patients).
- High doses: 420 or 700 mg three times a day in trials on hepatitis C and NASH, well tolerated, with no effect on hepatitis C.
- Duration: from 4 weeks (acute hepatitis) to 48 weeks (NASH), 4 months in diabetes, 41 months on average in the trial on cirrhosis.
- Absorption: silymarin passes poorly into the blood, as it is rapidly transformed and eliminated by the intestine or the liver.
- What does not work: nothing on chronic hepatitis C (154 patients), and no decrease in mortality in liver diseases caused by alcohol or hepatitis B and C according to the Cochrane review.
- Timing and meals: no study in this profile compares the timing of intake or taking it during a meal.
Did you know?
A meta-analysis of 19 trials deems it reasonable to use silymarin as a support in the treatment of poisonings by the death cap, the deadly mushroom, while it finds no evidence of an effect on viral hepatitis.
What the studies say
This thorough systematic review and meta-analysis, including 26 randomized clinical trials and 2,375 patients, evaluated the effects of silymarin in patients with NAFLD/NASH. The results suggest that silymarin administration significantly reduced several metabolic markers (total cholesterol, triglycerides, LDL-C, FI, HOMA-IR) and increased HDL-C. Furthermore, silymarin attenuated liver injury by reducing ALT and AST levels, and improved hepatic histology by decreasing steatosis. However, the authors emphasize that these effects will need to be confirmed by future research.
Li S, Duan F, Li S, Lu B. — Annals of hepatology (2024) — View the source study
Pairs well with
For information only: not a substitute for medical advice. Dietary supplements are not a replacement for a varied, balanced diet. Learn more