Milk thistle
A Cochrane review of 18 trials found no significant effect on deaths, liver complications or liver histology in alcohol-related or viral liver disease. In fatty liver disease, meta-analyses found lower liver enzymes at low to very low certainty, and a 48-week biopsy trial missed its main goal. Most trials found adverse events similar to placebo. One meta-analysis found twice the rate.
Add to Bio HackChecked 2026-11-09
- Status
- Dietary supplement in the US. Not FDA-approved for any condition.
- Also called
- Silybum marianum, silymarin, silybin, silibinin, Legalon, milk thistle extract, milk thistle seed
- Taken for
- liver health, fatty liver, liver detox, hangover, alcohol-related liver disease, hepatitis, cirrhosis, blood sugar
Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on
Shown to help2
Reported risks1
What people take it for, and what was found
Shown to help2
Fatty liver disease
Shown to lower liver enzymes in fatty liver disease, ALT by about 7 to 12 U/L, with low certainty and no data on deaths.
The numbers and sources
- Effect
- In 26 trials (2,375 patients), silymarin lowered ALT (pooled difference -12.39, 95% CI -19.69 to -5.08) and AST (-10.97, 95% CI -15.51 to -6.43), lowered total cholesterol, triglycerides and LDL, and improved steatosis on histology (OR 3.25, 95% CI 1.80 to 5.87) [5]. In a 48-week biopsy trial of 99 adults with NASH, a 30% or greater fall in disease activity score occurred in 32.7% on 700 mg three times a day and 26.0% on placebo (p 0.467). Fibrosis fell by 1 point or more in 22.4% against 6.0% (p 0.023) [6]. A 2025 Cochrane review of 17 RCTs (2,069 adults) found silymarin alone against placebo or no treatment may lower ALT by 7.21 U/L (95% CI -10.62 to -3.80, 6 trials, very low certainty). Silymarin complexes did not lower ALT, and no trial reported deaths or quality of life [7]. In a 2025 meta-analysis of 25 studies (2,283 patients), silymarin alone lowered LDL cholesterol (SMD -0.25), while ALT fell when silymarin was combined with diet or lifestyle change [8].
- Population
- Adults with fatty liver disease [5][7][8]. 99 adults with biopsy-proven NASH in Malaysia [6].
- Sources
- [5], [6], [7], [8]
- Caveats
- The meta-analysis authors state that the effects need confirmation [5]. The biopsy trial missed its primary outcome, and its fibrosis finding was secondary [6]. The Cochrane authors rated the evidence low to very low certainty and called benefits and harms unclear [7].
Blood sugar in type 2 diabetes
Shown to lower fasting glucose about 27 mg/dL and HbA1c about 1 point in adults with type 2 diabetes, in low quality trials.
The numbers and sources
- Effect
- In 5 trials (270 patients), silymarin lowered fasting blood glucose by 26.86 mg/dL (95% CI -35.42 to -18.30) and HbA1c by 1.07 points (95% CI -1.73 to -0.40). Lipids did not change [9]. A 2025 network meta-analysis of 17 studies (1,337 people with type 2 diabetes) found silymarin lowered fasting glucose, HOMA-IR and HbA1c against placebo (P < 0.05) [10]. Across 6 RCTs (673 participants), HOMA-IR fell by 2.29 (95% CI -4.55 to -0.03) with no change in fasting insulin. The fall was seen in type 2 diabetes but not in fatty liver disease [11].
- Population
- Adults with type 2 diabetes [9][10]; adults with type 2 diabetes, alcoholic cirrhosis or fatty liver disease in Iran, Egypt and Italy [11].
- Sources
- [9], [10], [11]
- Caveats
- The authors of [9] rated the evidence as low quality, with high heterogeneity. The network meta-analysis abstract reports p-values for silymarin against placebo without effect sizes [10]. The authors of [11] called the evidence limited.
Mixed results1
Liver detox
Mixed results: one meta-analysis found silymarin cut liver injury from tuberculosis drugs by two thirds at 4 weeks, while another found no enzyme fall in drug-induced liver injury.
Compared with placebo [12]; control groups the source does not describe [4]
The numbers and sources
- Effect
- Across 5 placebo-controlled trials (1,198 patients starting tuberculosis drugs), silymarin lowered drug-induced liver injury at week 4 (RR 0.33, 95% CI 0.15 to 0.75) and improved liver function (SMD -0.15, 95% CI -0.24 to -0.07) [12]. In a meta-analysis of 55 trials of liver injury from various causes, silymarin had no significant effect on AST or ALT in the drug-induced liver injury subgroup [4].
- Population
- 1,198 adults taking tuberculosis drugs in 5 RCTs [12]. Patients with drug-induced liver injury within 55 trials (3,545 patients) [4].
- Sources
- [12], [4]
- Caveats
- "Detox" is not a measured outcome. These trials tested protection of the liver from medicines. The protective effect was reported at week 4 [12]. The two reviews asked different questions, prevention in [12] and treatment of existing injury in [4].
Not shown to help1
Alcohol-related and viral liver disease
Not shown to lower deaths or liver complications in alcohol-related or viral liver disease. Results on liver enzymes disagreed.
The numbers and sources
- Effect
- Across 18 trials (1,088 patients), milk thistle did not significantly change all-cause mortality (RR 0.78, 95% CI 0.53 to 1.15), complications of liver disease (RR 0.95, 95% CI 0.83 to 1.09) or liver histology. Liver-related mortality was lower across all trials (RR 0.50, 95% CI 0.29 to 0.88) but not in the high-quality trials (RR 0.57, 95% CI 0.28 to 1.19) [1]. In 154 people with hepatitis C, 420 or 700 mg three times a day for 24 weeks did not lower ALT more than placebo. Two people in each group met the primary goal, and viral load and quality of life did not differ [2]. Reviews of liver enzymes in alcohol-related disease disagree. Across 15 RCTs (1,221 patients), silibinin capsules lowered ALT (SMD -1.16) and AST (SMD -1.56) [3]. A meta-analysis of 55 trials (3,545 patients) found no significant effect on AST or ALT in the alcohol-related liver disease subgroup [4].
- Population
- Adults with alcoholic liver disease or hepatitis B or C [1]. 154 adults in the US with hepatitis C not cleared by interferon [2]. Adults with alcohol-related liver disease [3]; adults with liver injury of several causes [4].
- Sources
- [1], [2], [3], [4]
- Caveats
- Only 28.6% of the Cochrane trials reported high methodological quality characteristics [1]. Enzyme changes are surrogate measures, and [3] did not report deaths.
Claimed, not studied in people1
Hangover
Not studied in people. In mice given binge doses of alcohol, silymarin limited the rise in the liver enzyme ALT and liver fat.
No study in people. This rests on animal studies.
The numbers and sources
- Effect
- In mice given three large doses of alcohol over 24 hours, silymarin given with the alcohol lessened the rise in serum ALT, liver fat, lipid peroxidation and liver TNF, and the fall in liver glutathione [13]. A review of 82 marketed hangover products found milk thistle extract among the most common ingredients and no peer-reviewed human data showing the safety or efficacy of any of the products [14].
- Population
- Mice, 6 per group [13]. 82 hangover products on the market [14].
- Sources
- [13], [14]
- Caveats
- The mouse study measured liver injury, not hangover symptoms such as headache, nausea or fatigue. No trial of milk thistle for hangover in people was located.
Doses studied
The NASH biopsy trial used 700 mg of silymarin three times a day for 48 weeks [6]. The hepatitis C trial used 420 or 700 mg three times a day for 24 weeks [2].
Risks
Mixed results1
Adverse events in trials
Mixed results: most reviews found adverse events about as common as on placebo, while one found more, mostly gut effects.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- Across the Cochrane trials, adverse events did not differ significantly from placebo or no intervention (RR 0.83, 95% CI 0.46 to 1.50) [1]. Adverse events were comparable with placebo at 420 and 700 mg three times a day [2], and did not differ between groups in the NASH trial [6]. In the 2025 Cochrane review of fatty liver trials, serious adverse events (Peto OR 1.55, 95% CI 0.26 to 9.28) and non-serious ones (RR 1.29, 95% CI 0.88 to 1.89) did not differ significantly from placebo or no treatment, at low and very low certainty [7]. A 2025 meta-analysis of fatty liver trials found more people with adverse effects on silymarin (RR 1.98, 95% CI 1.11 to 3.54), mostly gastrointestinal [8].
- Population
- Adults with liver disease in RCTs [1][6][2][7][8].
- Sources
- [1], [6], [2], [7], [8]
- Caveats
- Trials lasted up to about a year, so longer use was not studied.
Claims tested and not found
- That milk thistle lowers deaths in alcohol-related or viral liver disease. All-cause mortality did not change significantly across 18 trials [1].
- That high-dose silymarin lowers liver enzymes in hepatitis C. ALT did not fall more than placebo over 24 weeks [2].
- That silymarin improves NASH disease activity on biopsy. The share reaching a 30% fall in activity score did not differ from placebo [6].
Sources
- Rambaldi A, Jacobs BP, Gluud C. Milk thistle for alcoholic and/or hepatitis B or C virus liver diseases. Cochrane Database of Systematic Reviews. 2007. https://doi.org/10.1002/14651858.CD003620.pub3
- Fried MW, Navarro VJ, Afdhal N, et al. Effect of Silymarin (Milk Thistle) on Liver Disease in Patients With Chronic Hepatitis C Unsuccessfully Treated With Interferon Therapy: A Randomized Controlled Trial. JAMA. 2012. https://doi.org/10.1001/jama.2012.8265
- Wang Y, Yang W, Yang Y, et al. Evidence construction of Silibinin capsules against alcoholic liver disease based on a meta-analysis and systematic review. Frontiers in Pharmacology. 2025. https://doi.org/10.3389/fphar.2025.1516204
- Shahsavari K, Ardekani SS, Ardekani MRS, et al. Are alterations needed in Silybum marianum (Silymarin) administration practices? A novel outlook and meta-analysis on randomized trials targeting liver injury. BMC Complementary Medicine and Therapies. 2025. https://doi.org/10.1186/s12906-025-04886-y
- Li S, Duan F, Li S, Lu B. Administration of silymarin in NAFLD/NASH: A systematic review and meta-analysis. Annals of Hepatology. 2024. https://doi.org/10.1016/j.aohep.2023.101174
- Wah Kheong C, Nik Mustapha NR, Mahadeva S. A Randomized Trial of Silymarin for the Treatment of Nonalcoholic Steatohepatitis. Clinical Gastroenterology and Hepatology. 2017. https://doi.org/10.1016/j.cgh.2017.04.016
- Wang C, Shang Y, Kanaan G, et al. Silymarin for adults with metabolic dysfunction-associated steatotic liver disease. Cochrane Database of Systematic Reviews. 2025. https://doi.org/10.1002/14651858.CD015524.pub2
- Zhang Z, Li S, Sun J. Efficacy of different interventions for nonalcoholic fatty liver disease: A meta-analysis of lifestyle modifications, silymarin, and medications. Asia Pacific Journal of Clinical Nutrition. 2025. https://pubmed.ncbi.nlm.nih.gov/40738719/
- Voroneanu L, Nistor I, Dumea R, et al. Silymarin in Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Journal of Diabetes Research. 2016. https://doi.org/10.1155/2016/5147468
- Miao R, Zhang B, Zhou D, et al. Clinical Efficacy of Curcumin, Resveratrol, Silymarin, and Berberine on Cardio-Metabolic Risk Factors Among Patients With Type 2 Diabetes Mellitus: A Systemic Review and Bayesian Network Meta-Analysis. Phytotherapy Research. 2025. https://doi.org/10.1002/ptr.8431
- Yin S, Zhu F, Liu Y, Chen Q. Effects of silymarin on insulin resistance and sensitivity: A systematic review and meta-analysis of randomized controlled trials. Diabetes Research and Clinical Practice. 2025. https://doi.org/10.1016/j.diabres.2025.112008
- Tao L, Qu X, Zhang Y, et al. Prophylactic Therapy of Silymarin (Milk Thistle) on Antituberculosis Drug-Induced Liver Injury: A Meta-Analysis of Randomized Controlled Trials. Canadian Journal of Gastroenterology and Hepatology. 2019. https://doi.org/10.1155/2019/3192351
- Song Z, Deaciuc I, Song M, et al. Silymarin protects against acute ethanol-induced hepatotoxicity in mice. Alcoholism: Clinical and Experimental Research. 2006. https://doi.org/10.1111/j.1530-0277.2006.00063.x
- Verster JC, van Rossum CJI, Scholey A. Unknown safety and efficacy of alcohol hangover treatments puts consumers at risk. Addictive Behaviors. 2021. https://doi.org/10.1016/j.addbeh.2021.107029