Safety Profile
Overall safety rating: Generally Safe
Milk Thistle (Silymarin) Side Effects & Safety
This content is for informational purposes only and does not constitute medical advice. Consult your healthcare provider before starting any supplement. Full disclaimer
Potential Side Effects
- Mild GI discomfort (bloating, diarrhea, nausea) in ~2-10% of users
- Rare allergic reactions, particularly in people allergic to Asteraceae/Compositae family plants (ragweed, daisies)
- Mild laxative effect at higher doses
- Rare headache
Drug & Supplement Interactions
- May inhibit CYP2C9 and CYP3A4 at high doses — potential interaction with warfarin, statins, and certain medications metabolized by these enzymes
- May lower blood glucose — monitor closely if taking diabetes medications
- May reduce effectiveness of oral contraceptives through UGT enzyme induction
- Theoretical interaction with immunosuppressants (cyclosporine, tacrolimus) — consult physician
Maximum Dose
Do not exceed: 900mg silymarin/day (higher doses used in some clinical trials without adverse effects)
References
- Ferenci P, Dragosics B, Dittrich H, Frank H, Benda L, Lochs H, Meryn S, Base W, Schneider B (1989). Randomized controlled trial of silymarin treatment in patients with cirrhosis of the liver. Journal of Hepatology. DOI PubMed
- Saller R, Meier R, Brignoli R (2001). The use of silymarin in the treatment of liver diseases. Drugs. DOI PubMed
- Zhong S, Fan Y, Yan Q, Fan X, Wu B, Han Y, Zhang Y, Chen Y, Zhang H, Niu J (2017). The therapeutic effect of silymarin in the treatment of nonalcoholic fatty disease: A meta-analysis (PRISMA) of randomized control trials. Medicine. DOI PubMed
- Polyak SJ, Morishima C, Lohmann V, Pal S, Lee DY, Liu Y, Graf TN, Oberlies NH (2010). Identification of hepatoprotective flavonolignans from silymarin. Proceedings of the National Academy of Sciences. DOI PubMed