Does Milk Thistle Help Fatty Liver? Liver Enzymes Dip, Biopsies Mostly Don't Change
Silymarin, the extract in milk thistle, lowered liver enzymes modestly in pooled trials. Two 48-week biopsy trials did not meet their main goals, and an NIH-funded hepatitis C trial found no benefit.
By Kymata Health Editorial Published Last checked
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Key takeaways
From 10 sources- A meta-analysis of 8 trials (587 people) with fatty liver found silymarin lowered ALT by 9.16 U/L and AST by 6.57 U/L versus control1.
- In a 99-person biopsy trial, 700 mg three times a day for 48 weeks did not meet its main goal (32.7% vs 26.0% improved), though fibrosis improved more often (22.4% vs 6.0%)2.
- A US trial of 78 people found no benefit on liver biopsy at 420 or 700 mg three times a day (15% and 19% vs 12% on placebo)3.
- In 12 healthy men, silymarin lowered levels of losartan's active metabolite and, in one CYP2C9 genotype, raised losartan itself; a case report linked a milk thistle product to a rise in INR on warfarin67.
- NCCIH says milk thistle is usually well tolerated but product quality varies, with some products far off their label or contaminated8.
What this article covers
1 evidence profileThe evidence, graded
Pulled from the trial tables in our evidence profiles. Grades follow our evidence-grading policy.
Graded findings
5 rows- CGrade CLiver enzymes (ALT, AST) in fatty liver diseaseImproved AST −6.57 U/L and ALT −9.16 U/L versus control.Milk Thistle (Silymarin) · Meta-analysis · n=587 · 2017 · PMID 29245314
- CGrade CLiver histology in NASH (biopsy-proven)Mixed Main outcome (30% drop in activity score) did not differ (32.7% vs 26.0%); fibrosis improved in 22.4% vs 6.0%.Milk Thistle (Silymarin) · RCT · n=99 · 2017 · PMID 28419855
- CGrade CLiver histology in NASH without cirrhosisNo effect Histological improvement in 15% (700 mg), 19% (420 mg) and 12% (placebo); no significant difference. Well tolerated.Milk Thistle (Silymarin) · RCT · n=78 · 2019 · PMID 31536511
- ∅No effectALT in chronic hepatitis C after failed interferonNo effect Only 2 people per group met the ALT goal; no difference in ALT, viral load or quality of life. Side effects matched placebo.Milk Thistle (Silymarin) · RCT · n=154 · 2012 · PMID 22797645
- CGrade CMortality and complications in alcohol-related or hepatitis B/C liver diseaseNo effect No significant effect on all-cause mortality (RR 0.78), complications or histology; liver-related mortality was lower across all trials but not in the high-quality trials.Milk Thistle (Silymarin) · Systematic review · n=1,088 · 2007 · PMID 17943794
Where these trials agree: Milk Thistle (Silymarin) and liver, counted row by row in the Consensus finder.
The short answer
Milk thistle can nudge liver enzymes down in fatty liver disease, but trials that looked at the liver tissue itself have not shown a clear benefit123. NCCIH says results for fatty liver and other liver diseases have been conflicting or too limited to draw conclusions8.
Fatty liver disease is now formally called metabolic dysfunction-associated steatotic liver disease (MASLD)9. The trials below used the older names, NAFLD and NASH12.
Liver enzymes: a modest drop
A 2017 meta-analysis pooled 8 randomized trials with 587 people who had non-alcoholic fatty liver disease1. Silymarin lowered AST by 6.57 U/L (95% CI −10.03 to −3.12) and ALT by 9.16 U/L (95% CI −16.24 to −2.08) more than control groups1.
Liver enzymes are blood markers, not liver outcomes such as scarring or cirrhosis1. The review authors reported no conflicts of interest1.
Biopsy trials: no clear win
A Malaysian trial gave 99 adults with biopsy-proven NASH 700 mg of silymarin or placebo three times daily for 48 weeks, then repeated the biopsy2. The main goal, a 30% or greater drop in disease activity score, was reached by 32.7% on silymarin vs 26.0% on placebo, not a significant difference (P = .467)2. Fibrosis improved by at least 1 point in 22.4% vs 6.0% (P = .023), which the authors said needs confirming in a larger trial2.
A US multicentre phase II trial randomized 78 adults with NASH without cirrhosis to 420 mg or 700 mg of a branded silymarin (Legalon) or placebo three times daily for 48 weeks3. The main histology goal was met by 15%, 19% and 12%, with no significant difference (p = 0.79)3. Central review found 63% of participants did not meet histological entry criteria3.
One author of that trial was an employee of the Italian subsidiary of Rottapharm|Madaus, maker of the silymarin used, at the time of the study, and the biopsy pathologist was paid by the company for her review3. The trial began with NIH funding (NCCAM, now NCCIH), but Rottapharm|Madaus took over sponsorship in 20093. NCCIH lists it among the studies it funded that showed no benefit8.
Hepatitis and alcohol-related liver disease
In an NIH-funded JAMA trial of 154 people with chronic hepatitis C whose interferon therapy had failed, silymarin at 420 or 700 mg three times a day for 24 weeks did not lower ALT more than placebo; only 2 people per group met the goal48.
A Cochrane review of 18 trials (1,088 people) with alcohol-related or hepatitis B or C liver disease found no significant effect on death from any cause (relative risk 0.78), complications or liver histology5. A lower liver-related death rate across all trials disappeared when only high-quality trials were counted5.
Safety and who should avoid it
- Allergy to ragweed, chrysanthemum, marigold or daisy: milk thistle may cause allergic reactions8.
- People on losartan: in 12 healthy Chinese men, 140 mg of silymarin three times daily for 14 days lowered levels of losartan's active metabolite (E-3174) in both CYP2C9 genotypes tested, and raised losartan itself only in men with the CYP2C9*1/*1 genotype; it was a drug-level study, so the effect on blood pressure is unknown6.
- People on warfarin: in one case report, INR rose from 2.64 to 4.12 after starting a liver-cleanse supplement with 200 mg of milk thistle and normalized after stopping7.
- People on diabetes medicines: pooled small trials found lower fasting glucose and HbA1c with silymarin, so ask whether glucose could fall further10.
- Pregnancy and breastfeeding: little is known about safety8.
- Anyone with diagnosed liver disease: trials did not show benefit on their main outcomes, so this is not a substitute for medical care345.
Quick answers
Common questions
4 answersWhat dose of milk thistle was studied for fatty liver?
Can milk thistle detox or cleanse the liver?
No trial cited here tested a cleanse; NCCIH says liver trial results have been conflicting or too limited to draw conclusions8.
Does milk thistle lower blood sugar?
A meta-analysis of 5 small trials in type 2 diabetes found lower fasting glucose and HbA1c, but the evidence was low quality10.
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Where to buy Milk Thistle (Silymarin)
Products from brands we partner with that contain Milk Thistle (Silymarin). Check the amount per serving against the doses studied, and the label for other ingredients.
Milk Thistle (Silymarin) products from partner brands
2 products Paid links · we earn a commission- Quick pickBotanic ChoiceBotanic Choice Milk Thistle Extract, 90 capsules
1 capsule: 100 mg milk thistle seed extract (80% silymarin by UV, 30% by HPLC); label directions 1 capsule 3 times daily
$12.00one-timeChecked Oct 12, 2026 - SupersmartSilyplus5% off with the Supersmart newsletterGet 5% off with the newsletter (paid link, opens in new tab)
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3 capsules: 360 mg Siliphos (120 mg per capsule; milk thistle extract standardized to 33% silybin, about 119 mg silybin a day; also contains soy lecithin); 30 servings. This is a silybin-standardized extract, far below the 1,260–2,100 mg a day of standard silymarin used in the liver trials. Contains soy.
$32.00one-time$27.20subscribeChecked Oct 11, 2026
References
10 sources. Numbers in the text link here.
Sources cited in this article
10 sources- 1The therapeutic effect of silymarin in the treatment of nonalcoholic fatty disease: A meta-analysis (PRISMA) of randomized control trialsMedicine (Baltimore), 2017 · PMID 29245314
- 2A Randomized Trial of Silymarin for the Treatment of Nonalcoholic SteatohepatitisClin Gastroenterol Hepatol, 2017 · PMID 28419855
- 3Silymarin in non-cirrhotics with non-alcoholic steatohepatitis: A randomized, double-blind, placebo controlled trialPLoS One, 2019 · PMID 31536511
- 4Effect of silymarin (milk thistle) on liver disease in patients with chronic hepatitis C unsuccessfully treated with interferon therapy: a randomized controlled trialJAMA, 2012 · PMID 22797645
- 5Milk thistle for alcoholic and/or hepatitis B or C virus liver diseasesCochrane Database Syst Rev, 2007 · PMID 17943794
- 6Effect of silymarin on the pharmacokinetics of losartan and its active metabolite E-3174 in healthy Chinese volunteersEur J Clin Pharmacol, 2009 · PMID 19221727
- 7CYP2C9-mediated warfarin and milk thistle interactionJ Clin Pharm Ther, 2020 · PMID 31633199
- 8Milk Thistle: Usefulness and Safety (Last Updated: February 2025)National Center for Complementary and Integrative Health (NCCIH), 2025
- 9A multisociety Delphi consensus statement on new fatty liver disease nomenclatureHepatology, 2023 · PMID 37363821
- 10Silymarin in Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis of Randomized Controlled TrialsJ Diabetes Res, 2016 · PMID 27340676
Milk Thistle (Silymarin) and other dietary supplements are not intended to diagnose, treat, cure or prevent any disease, and these statements have not been evaluated by the FDA. Talk to your clinician or pharmacist before starting a supplement, especially if you take prescription medicines. Product links on this page are paid partner links.