Is Ashwagandha Safe To Take With Anastrozole?

In our latest question and answer, our pharmacist discusses whether or not anastrozole can be taken with ashwagandha.

2 min read Updated Jun 2026 Read by 4,898 people
Is Ashwagandha Safe To Take With Anastrozole?
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Denise asked

Hello, can I take Ashwagandha if I’m taking anastrozole?

Jan 21, 2023
The quick answer
  • There is no known interaction between ashwagandha and anastrozole based on available evidence. Ashwagandha does not significantly affect the enzymes or metabolic pathways that anastrozole uses in the body. You should inform your doctor about all supplements and medications you take so they can monitor you appropriately.
A quick summary of Dr. Brian Staiger, PharmD's full answer below, condensed by AI from that answer only (not from any outside source). The pharmacist's answer is the source of record.
Medications in this answer — tap to explore

Answer

Thanks for reaching out! There is no known interaction between Arimidex (anastrozole) and ashwagandha. 

Although it can sometimes be challenging to definitively know whether or not an herbal product will cause a drug interaction due to the lack of available data, based on everything I could find, they seem to be safe to take together.

Nevertheless, be sure to let your doctor know about everything you are taking so you can be appropriately monitored.

More Details

Drugs and herbs can interact in a variety of ways, including by affecting one or the other's metabolism and absorption, or by a combined or contradictory pharmacologic effect.

For example, the herb 'cat's claw' can inhibit a prominent CYP metabolizing enzyme known as CYP3A4, which could decrease the metabolism of other drugs that depend on the enzyme, potentially increasing the risk of side effects.

Ashwagandha isn't known to inhibit metabolizing enzymes to a clinically significant degree, and besides, anastrozole is not predominately metabolized by the CYP enzymes. It is metabolized via other methods (e.g., occurs by N-dealkylation, hydroxylation, and glucuronidation) that ashwagandha isn't known to affect.

In fact, ashwagandha isn't known to interact with many prescription drugs. One of the few may be with thyroid medication but there is no evidence to suggest there are any issues with anastrozole. Ashwagandha is not known to affect estrogen levels either.

Final Words

Thanks again for contacting us. I hope this was helpful.

I want to reiterate that you should make sure your doctor knows of all the medications you are taking so you can be appropriately monitored.

While there is no known interaction with anastrozole, again, there just really isn't much data to make firm conclusions (even though it's likely they are safe together).

References & sources
  1. Efficacy and Safety of Ashwagandha Root Extract in Subclinical Hypothyroid Patients: A Double-Blind, Randomized Placebo-Controlled Trial — PubMed
  2. An in vitro evaluation of human cytochrome P450 3A4 inhibition by selected commercial herbal extracts and tinctures — PubMed
  3. Anastrozole Monnograph — PubChem
  4. Arimidex Prescribing Information — AccessFDA
Glossary — Terms in This Answer
Arimidex
A brand name for the drug anastrozole, used to treat certain types of breast cancer.
Anastrozole
A prescription medication that reduces estrogen levels in the body, commonly used in breast cancer treatment.
Ashwagandha
An herbal supplement derived from a plant, traditionally used in natural medicine practices.
Drug interaction
When two substances affect each other's action in the body, potentially changing how either one works.
Metabolism
The process by which your body breaks down and processes drugs and other substances.
CYP enzymes
Proteins in your body that help break down and eliminate many medications from your system.
Inhibit
To slow down or prevent a process from happening normally.
Glucuronidation
A chemical process the body uses to break down and eliminate certain drugs.
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Dr. Brian Staiger, PharmD
About the pharmacist

Dr. Brian Staiger, PharmD

Clinical Pharmacy

Doctor of Pharmacy, board certified clinical pharmacist (BCPS), American Herbalist Guild, Medication Therapy Management certified

Brian Staiger, PharmD, BCPS, is a licensed pharmacist with more than 13 years of experience across retail pharmacy, clinical pharmacy, medication safety, pharmacy program development, and healthcare administration. He is the founder of HelloPharmacist.com, where he helps patients...

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