Milk Thistle: Clinical Evidence & Substantiation Summary

Clinical Trials
58
Strongest Evidence
Liver Health & Detoxification
Typical Dosage
140–420 mg/day (silymarin equivalent)
Common Forms
Milk thistle extract (standardised to 80% silymarin)

What Is Milk Thistle?

Milk Thistle (Silybum marianum) is a botanical extract containing silymarin, a complex of flavonolignans with potent antioxidant and hepatoprotective properties. It is the most studied herbal supplement for liver support.

Mechanism of action: Silymarin acts as a radical scavenger and inhibits lipid peroxidation. It also increases ribosomal RNA synthesis, stimulating liver cell regeneration, and inhibits the binding of toxins to hepatocyte cell membrane receptors.

Clinical Evidence Summary

Below are 3 key clinical studies on Milk Thistle. Nutra Comp analyses 58+ studies in its full clinical evidence report.

Systematic review and meta-analysis2017PMID: 28612110

Milk thistle for liver health: meta-analysis

Population: 19 RCTs

Key finding: Milk thistle supplementation significantly reduced liver enzymes ALT and AST (p<0.01) in patients with NAFLD and hepatitis populations.

Meta-analysis2020PMID: 32432219

Silymarin and metabolic parameters in diabetes

Population: 7 RCTs

Key finding: Silymarin supplementation significantly reduced fasting glucose and HbA1c (p=0.03) in type 2 diabetes patients, likely through improved hepatic insulin sensitivity.

RCT crossover2019PMID: 31142457

Phytosome technology and silybin bioavailability

Population: 12 healthy adults

Key finding: Silybin phytosome (Siliphos) showed 4–5x higher bioavailability compared to standardized 80% silymarin extracts.

Evidence-Based Structure–Function Claims

Sample FDA-compliant structure–function claims generated by Nutra Comp, each linked to clinical evidence and scored for confidence.

9
Supports healthy liver function and detoxification
Category: Liver Health · Confidence: 9/10
8
Provides potent antioxidant support for hepatocyte integrity
Category: Antioxidant · Confidence: 8/10
7
Supports healthy metabolic parameters already within the normal range
Category: Metabolism · Confidence: 7/10

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Related Ingredients

NAC (N-Acetyl Cysteine)
53 studies · Antioxidant & Detoxification
Berberine
47 studies · Blood Sugar Support
Turmeric
91 studies · Inflammatory Response

Key Terms

Randomised Controlled Trial (RCT)BioavailabilityStandardised Extract

Frequently Asked Questions

Is milk thistle FDA approved?

Milk thistle is sold as a dietary supplement. In Europe, silymarin extracts (Legalon) are used as drugs for toxic liver damage and cirrhosis. It is not FDA approved as a drug in the US.

How long should I take milk thistle?

Most clinical studies for liver enzyme reduction last 8 to 24 weeks. It is considered safe for long-term use.

Does milk thistle help with skin?

By supporting hepatic detoxification and providing systemic antioxidant support, some users notice improvements in skin clarity, though direct clinical evidence for acne is limited.

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