Home
Scan
Ask
Protocols
Profile
HomeIngredientsMilk Thistle
Reviewed by the Scan Dose Research Team and Clinical Advisory Board

Milk Thistle

MODERATE EVIDENCEBotanicalLast updated April 2026

SCAN DOSE SUMMARY

Milk thistle's active compound silymarin is the most studied hepatoprotective (liver-protective) natural compound, with evidence spanning alcoholic liver disease, NAFLD, drug-induced liver injury, and hepatitis. Our research shows it genuinely protects liver cells — but the bioavailability of standard silymarin is very poor. Phytosomal forms (Siliphos, Silybin Phytosome) dramatically improve absorption and clinical outcomes.

EVIDENCE GRADES

NAFLD (liver enzymes, steatosis)Moderate — multiple positive RCTs (PMID: 28231535)
B
Drug-induced liver injury (DILI)Moderate — used clinically
B-
Alcoholic liver diseaseModerate — improved liver function markers
B-
Hepatitis C (adjunct)Mixed — some viral load reduction
C+
Chemotherapy hepatoprotectionPreliminary positive data
C+
Blood sugar (in diabetics with liver disease)Moderate — dual mechanism
B-

OPTIMAL DOSAGE

  • Standard silymarin extract (80%): 420-600mg/day in 3 divided doses
  • Silybin phytosome (Siliphos): 160-480mg/day (dramatically better absorbed)
  • Liver protection (acute): 600-800mg/day
  • Take with food — fat improves absorption of all forms
Scan a supplement containing Milk Thistle

DRUG INTERACTIONS

CYP3A4 substratesModerate

Silymarin inhibits CYP3A4 in vitro; clinical significance debated

CYP2C9 substrates (warfarin)Moderate

In vitro inhibition; may increase warfarin levels

UGT substratesModerate

Silymarin inhibits glucuronidation; may affect drug clearance

Sirolimus (rapamycin)Moderate

Case report of increased sirolimus levels

MetforminMinor

Silymarin may enhance metformin's effects on blood sugar

StatinsModerate

Both metabolized via CYP3A4; potential for increased statin levels

SAFETY PROFILE

Drug Interactions

Side Effects

  • Mild GI effects (diarrhea, nausea) — most common
  • Allergic reactions in ragweed/Asteraceae-allergic individuals (cross-reactivity)
  • Generally very well tolerated

Pregnancy & Lactation

  • Traditionally used as a galactagogue. Limited safety data for pregnancy — avoid supplemental doses.

WADA Status

Not Prohibited

HOW SCAN DOSE SCORES THIS

Phytosomal forms (Siliphos, Silybin Phytosome) score significantly higher than standard silymarin — 4-10x better bioavailability
Products using standardized 80% silymarin: acceptable but note bioavailability limitation
CYP interaction screen for users on narrow therapeutic index drugs (warfarin, sirolimus, cyclosporine)
Ragweed/Asteraceae allergy warning
Liver enzyme monitoring recommended for therapeutic use — both to track improvement and to ensure no paradoxical reaction
"Liver detox" marketing claims: flag — silymarin is hepatoprotective, not a "detox"

CLINICAL REFERENCES

1.

Zhong S et al. The therapeutic effect of silymarin in NAFLD: a meta-analysis.

PMID: 28231535

2.

Abenavoli L et al. Milk thistle in liver diseases: past, present, future.

PMID: 20564545

3.

Kidd P, Head K. A review of the bioavailability and clinical efficacy of milk thistle phytosome.

PMID: 19801149

4.

Voroneanu L et al. Silymarin in type 2 diabetes mellitus: a systematic review and meta-analysis.

PMID: 29080460

RELATED RESEARCH

Apigenin
ApigeninChamomile extract
Apocynum Venetum
ArjunaArjuna bark
Scan Your Milk Thistle SupplementBrowse all ingredients

Reviewed by the Scan Dose Research Team and Clinical Advisory Board | Last updated: April 2026

Not medical advice. Based on published clinical research and systematic reviews.

Discover More

Explore
Browse All 538 IngredientsBrowse All 20 Conditions