Milk thistle
Silymarin / Silybum marianum · Longevity
The default "liver supplement", with a trial record far more ambiguous than its reputation.
What the evidence says
Silymarin has plausible antioxidant and membrane-stabilising mechanisms, and intravenous silibinin is licensed in parts of Europe for Amanita mushroom poisoning (it is not a routine FDA-approved US treatment, and emergency toxicology does not validate an oral retail capsule). For chronic liver disease the controlled evidence is weak and inconsistent — a well-run NIH trial in hepatitis C found no benefit on liver enzymes or viral load. The gap between "liver support" marketing and measured outcomes is wide.
What studies used
Studies commonly used 140–420 mg/day of silymarin. Published studies had not established a preferred timing.
Reported from published studies and product labelling — a record of what was used in research, not a recommendation. What is right for you is a conversation with a clinician.
Watch out for
- Taking it alongside anything hepatotoxic — oral steroids, high-dose niacin, heavy alcohol — treats a symptom of a problem still in progress
- Can interact with drugs cleared by CYP enzymes
Evidence base
established literature
Strong human evidence: either a phase 3 or 4 trial report alongside review-level evidence, or ten or more randomised controlled trial reports.
This letter measures how much human research exists, not whether it works for you — the tier above (Limited) is the read on quality.
Research (12)
- Milk thistle in liver diseases: past, present, futurePhytother Res · 2010
- Milk thistle (Silybum marianum): A concise overview on its chemistry, pharmacological, and nutraceutical uses in liver diseasesPhytother Res · 2018
- Milk thistleAm Fam Physician · 2005
- Safety and toxicity of silymarin, the major constituent of milk thistle extract: An updated reviewPhytother Res · 2019
- Milk Thistle (Silybum marianum): Potential Role in Cancer PreventionCurr Med Chem · 2025
- Milk thistle (Silybum marianum (L.)Gaertn.): An overview about its pharmacology and medicinal uses with an emphasis on oral diseasesJ Oral Biosci · 2022
- Use of Milk Thistle in Farm and Companion Animals: A ReviewPlanta Med · 2023
- Silymarin (milk thistle extract) as a therapeutic agent in gastrointestinal cancerBiomed Pharmacother · 2021
- Milk thistle (Silybum Marianum) as an antidote or a protective agent against natural or chemical toxicities: a reviewDrug Chem Toxicol · 2020
- Milk thistle and the treatment of hepatitisGastroenterol Nurs · 2001
- Milk thistle for alcoholic and/or hepatitis B or C virus liver diseasesCochrane Database Syst Rev · 2007
- Milk thistle for alcoholic and/or hepatitis B or C virus liver diseasesCochrane Database Syst Rev · 2005
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