Herb Profile
Milk Thistle Silybum Marianum
Silybum marianum
Milk Thistle (Silybum marianum) is traditionally used for liver support, with its flavonolignan complex silymarin studied for antioxidant, anti inflammatory, and hepatoprotective activity.
Last reviewed: •4 sources citedReport a correctionProfile-wide ·B Moderate
Use extra caution — Generally safe; mild GI upset; possible allergic reactions Details
- Evidence
- Moderate Evidence
- Typical onset
- Varies by prep
- Safety rating
- Moderate caution
- Best for
- Antioxidant, Liver Protective, Stress resilience, Inflammatory signaling
- Avoid / review if
- Ragweed Allergy, CYP/Transporter Effects Reported In Vitro, Clinically Significant Interactions Not Well Established
Safety
Safety & Cautions
Generally safe; mild GI upset; possible allergic reactions
Elevated caution
Caution level: Elevated. One caution category applies — read it before use.
- Liver-SensitiveLiver-related caution language appears in the profile.
Detailed safety fields
Pregnancy, breastfeeding, and contraindications
- Ragweed Allergy
- CYP/Transporter Effects Reported In Vitro
- Clinically Significant Interactions Not Well Established
Safety classifications
- Liver-Sensitive: Liver-related caution language appears in the profile.
Full safety note
- Generally safe; mild GI upset; possible allergic reactions
Safety labels
- Liver-Sensitive
Evidence
Evidence Summary
Evidence lens
Useful signal, but study design, dose, and population still matter.
ModerateModerate Evidence
Human clinical evidence: Present in source signals
Mechanistic / preclinical: Mechanism mapped — Oxidative Stress Modulation · Cellular Protection · NF KB Modulation
Research maturity: Established research — Long Term Human Evidence May Be Limited.
Safety boundary: Safety note available — Generally safe; mild GI upset; possible allergic reactions
This profile cites 4 human studies.
Study design details
Evidence Grade
Grade B: Moderate Evidence
Evaluation of methodological rigor, population reach, and evidence alignment.
- Design Match
- Meta-analysis
- Risk of Bias
- Low
- Consistency
- Consistent
Strongest recorded design is a meta-analysis, drawn from 8 recorded studies, 5 in people. No disagreement is recorded across them.
How evidence grades work
Each grade reflects the strength and consistency of published human evidence — not marketing claims. Grades are based on study count, design quality, effect size, consistency, and recency.
- Strong
- Multiple RCTs, consistent direction, adequate effect size
- Moderate
- Some RCTs or consistent observational data in humans
- Preliminary / Mixed
- Animal or in-vitro only, or conflicting human data
- Traditional / Theoretical
- Traditional use only; no controlled human trials
Clinical Study Summaries (8)5 human evidence sources · 2 human trials · ~99 participants across 1 human evidence source with reported N · Consistency not yet classifiable
Filter by study class
Showing 8 of 8 studies.
What the evidence actually shows
This table contains 8 structured sources, including 5 human evidence sources; 2 are human trials. Across 1 human evidence source with a reported sample size, the approximate participant total is 99; overlapping publications may include some of the same people.
| Study | Design | N | Dose | Duration | Population | Outcome | Result & magnitude | Source |
|---|---|---|---|---|---|---|---|---|
Background | Meta-analysis Statistically combines results from multiple eligible studies; confidence still depends on the quality, consistency, and directness of those studies. | — | — | — | — | — | Silymarin significantly reduced AST and ALT in pooled randomized evidence, while ALP did not significantly improve. | PubMed → |
Background | Meta-analysis Statistically combines results from multiple eligible studies; confidence still depends on the quality, consistency, and directness of those studies. | — | — | — | — | — | A meta-analysis of 13 randomized trials (915 participants) found no convincing high-quality evidence for clinically important liver-disease outcomes. Study quality and heterogeneity were major limitations. | PubMed → |
Background | Meta-analysis Statistically combines results from multiple eligible studies; confidence still depends on the quality, consistency, and directness of those studies. | — | — | — | — | — | Silymarin reduced CRP, IL-6, and MDA, while IL-10, total antioxidant capacity, and glutathione did not clearly improve. | PubMed → |
A Randomized Trial of Silymarin for the Treatment of Nonalcoholic Steatohepatitis PubMed · Clin Gastroenterol Hepatol · 2017 Background | Randomized controlled trial Randomly assigns participants to interventions or controls, reducing many sources of bias when the trial is conducted well. | n=99 | — | — | — | — | — | PubMed → |
Background | Randomized controlled trial Randomly assigns participants to interventions or controls, reducing many sources of bias when the trial is conducted well. | — | — | — | — | — | A 2025 randomized double-blind crossover PK trial in 16 healthy adults found a micellar 130-mg silymarin formulation produced about 18.9-fold higher Cmax and 11.4-fold higher 24-hour AUC than a standard product. No adverse events were observed in this small single-dose study. Higher exposure is not evidence of superior clinical efficacy. | PubMed → |
Abenavoli L et al. · Phytother Res · 2018 Background | Narrative review Summarizes selected literature without the full prespecified search and selection methods of a systematic review. | — | — | — | — | — | — | PubMed → |
Show 2 more studies
Safety and toxicity of silymarin, the major constituent of milk thistle extract: An updated review Soleimani V et al. · Phytother Res · 2019 Background | Narrative review Summarizes selected literature without the full prespecified search and selection methods of a systematic review. | — | — | — | — | — | — | PubMed → |
PubMed indexed authors · 2006 Background | Narrative review Summarizes selected literature without the full prespecified search and selection methods of a systematic review. | — | — | — | — | — | — | PubMed → |
Dosing & Timing
- Dose guidance
- Standardized extract (70 80% silymarin): 140 420 mg/day in divided doses; variability in silybin content
How Milk Thistle Silybum Marianum works
Simplified mechanism pathway based on preclinical and pharmacological evidence. Does not confirm clinical efficacy.
Mechanism Pathway — How Milk Thistle Silybum Marianum Works
CompoundTarget / ReceptorMechanismEffect / Outcome
Mechanisms & biological pathways (preclinical)
- Oxidative Stress Modulation
- Cellular Protection
- NF KB Modulation
- Nrf2 Activation
Active Compounds
Key constituents studied in Milk Thistle Silybum Marianum, with full pharmacology and safety profiles.
- Silibinin — active compound in Milk Thistle Silybum Marianum
- Silybin — active compound in Milk Thistle Silybum Marianum
- Silychristin — active compound in Milk Thistle Silybum Marianum
- Silydianin — active compound in Milk Thistle Silybum Marianum
- Silymarin — active compound in Milk Thistle Silybum Marianum
Compare related active botanicals
Explore botanicals with similar chemistry, effects, or safety considerations in the Botanical Activity Atlas.
Compare & Sourcing
Compare side-by-side tradeoffs or verify active marker guidelines.
Sourcing options
Milk Thistle product picks
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Product form & quality guidelines
When sourcing Milk Thistle Silybum Marianum, verify the label for:
- Standardized extract: Confirm active content percentages on the supplement facts panel (e.g. standardized to specific marker compounds) rather than simple raw herb weights.
- Third-party testing: Look for independent purity labels (USP, NSF, ConsumerLab, or Eurofins) to ensure the product is free from heavy metals, solvents, and contaminants.
- Form bioavailability: Ensure the form matches evidence-supported configurations (e.g. standardized active extracts like bacosides, withanolides, or curcuminoids) for optimal onset and digestion tolerance.
Safety first · Harm reduction
This information is educational and not medical advice. Start low, avoid risky combinations, and consult a licensed clinician before making health decisions—especially if you use medications, have diagnosed conditions, or are pregnant/breastfeeding.
Learn how we evaluate confidence, safety, and intensity on the methodology page.
Founder & Head Researcher · Oak Ridge, TN · Last reviewed August 2026
Editorial Review
Checked against primary sources, cited evidence, and contraindication language before publication. Evidence claims, safety language, and affiliate modules are reviewed independently. Not personal medical advice.
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