Does Saw Palmetto Interact With Estradiol?

In our latest question and answer, the pharmacist discusses the potential interaction between saw palmetto and estradiol.


Can saw palmetto interact with estradiol and cause side effects like headaches? Thanks!

Asked by Iisa On Jun 02, 2024

Answered by
Medical Content Reviewed By HelloPharmacist Staff

Published Jun 03, 2024
Last updated Jun 14, 2024


Thank you for your question! Our drug-herbal interaction checker does show an interaction between saw palmetto and estradiol (Saw Palmetto - Estradiol Interaction Details | HelloPharmacist). Studies indicate that saw palmetto may have anti-estrogenic activity and therefore may interact with estrogen-containing drugs, such as estradiol.

We based our 'moderate interaction' rating between saw palmetto and estrogens on several studies, including one published in European Urology (Evidence that Serenoa repens extract displays an antiestrogenic activity in prostatic tissue of benign prostatic hypertrophy patients - PubMed (

In this study, one group of individuals received saw palmetto extract, while the other received a placebo for three months. Researchers examined how the treatment affected estrogen and androgen receptors in prostate tissue. They found that saw palmetto significantly reduced certain estrogen receptor levels compared to the untreated group. This suggests that saw palmetto might have antiestrogenic effects.

It is certainly possible that if you take both estrogen and saw palmetto, estrogen levels may be affected, which could cause side effects, such as the headache you mentioned in your question.

It is important to note that while the interaction between saw palmetto and estradiol is possible, we don't know how clinically significant it is due to the overall lack of data. Our interaction checker is based on available literature, but there isn't much to go off of, unfortunately.

While there may be concern about taking saw palmetto with estradiol, it is very challenging to say exactly what the effects may be and if it could cause an increase in side effects or reduce the effectiveness of estrogen therapy.

I always highly recommend speaking to your doctor before combining supplements with your medication so you can be appropriately monitored.

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  • Evidence that Serenoa repens extract displays an antiestrogenic activity in prostatic tissue of benign prostatic hypertrophy patients, PubMed
  • Activity and isolated phytoestrogen of shrub palmetto fruits (Serenoa repens Small), a new estrogenic plant, PubMed
  • Myristoleic acid, a cytotoxic component in the extract from Serenoa repens, induces apoptosis and necrosis in human prostatic LNCaP cells, PubMed

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Dr. Brian has been practicing pharmacy for over 13 years and has wide-ranging experiences in many different areas of the profession. From retail, clinical, program development, and administrative responsibilities, he's your knowledgeable and go-to source for all your pharmacy and medication-related questions! Dr. Brian Staiger also has herbalist training and educational certificates in the field of medical ethnobotany. Feel free to send him an email at [email protected]! You can also connect with Dr. Brian Staiger on LinkedIn.

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