Short answer

We found no documented interaction between Ashwagandha and Milk thistle in the sources below. That isn't proof the combination is right for you: check each one's cautions, and ask your pharmacist if you take medication.

Ashwagandha

What it is: A plant root used in traditional Ayurvedic and Unani medicine, often called an adaptogen.

What the research says: Several small trials of 6 to 8 weeks found people felt less stress and anxiety, with doses around 500 to 600 mg a day working better than lower ones. A few small studies suggest a modest sleep benefit. It has not been studied thoroughly.

Cautions

• Well tolerated for up to about 3 months; long-term safety isn't known.
• Mild side effects can include upset stomach, loose stools, nausea and drowsiness.
• It has been linked to liver injury in some people.
• Not for people who are pregnant or breastfeeding, or who have prostate cancer.

Medicines to check

• Thyroid medicine (ashwagandha may affect how the thyroid works)
• Diabetes and blood-pressure medicines
• Sedatives
• Medicines that suppress the immune system

In Holitro: Ashwagandha (500 mg per capsule)

Source: NIH Office of Dietary Supplements: Ashwagandha: Fact Sheet for Consumers (updated December 2023)

Milk thistle

What it is: A flowering plant whose extract, silymarin, is sold for liver health.

What the research says: There isn't enough good evidence to draw conclusions. Small studies suggest it may help blood sugar in type 2 diabetes; liver-disease trials have been conflicting.

Cautions

• Usually well tolerated; it can cause bloating, nausea or gas.
• It can trigger allergies in people allergic to ragweed, daisies or marigolds.
• Little is known about use in pregnancy or breastfeeding.

Medicines to check

• Talk to your clinician if you take any medicine

In Holitro: Milk Thistle (450 mg per capsule)

Source: NIH National Center for Complementary and Integrative Health: Milk Thistle: Usefulness and Safety (updated February 2025)

Check with your doctor or pharmacist, especially if you take medication.

Check your stack — free

Educational information only, not medical advice. This reflects general ingredient overlap, not a personalized safety review. Always check with your doctor or pharmacist before combining supplements, especially if you take medication, are pregnant or nursing, or manage a health condition. These statements have not been evaluated by the FDA.