June 2, 2021: Does Saw Palmetto Improve the Symptoms of Benign Prostatic Hypertrophy (BPH)?

Saw palmetto (SP) is a popular herbal preparation derived from the fruit of the bushy palm Serenoa repens. SP is available OTC in multiple formulations such as liquid extracts, tablets, capsules, tea, and is often combined with other herbal supplements. SP is most frequently used for treatment of urinary symptoms due to BPH.

The active components of the palmetto extracts are thought to be volatile oils and free fatty acids which inhibit 5-alpha-reductase and the conversion of testosterone to dihydrotestosterone (in vitro evidence but not in humans).

There have been some trials regarding its’ efficacy in treating the symptoms of BPH. In 2006, a double-blind, placebo controlled randomized trial of SP administered to 225 men with moderate to severe symptoms was published in NEJM.  SP did not improve symptoms or objective measures of BPH. A similar study was published in JAMA in 2011 with the same  negative results. Other trials have reported small improvements with use of the herb, but were limited by small numbers, short duration, failure to use standard outcome measures and the issue of blinding (SP has a strong pungent odor).  Furthermore, concentration of active ingredient is not standardized and there may be a critical concentration that is required to produce an effect.

Adverse effects are few and include abdominal pain, fatigue, headache, and rhinitis.  A case of hepatitis and pancreatitis has been reported but cause and effect are questionable. 

BUT-consider it for androgenic alopecia………

Although high quality data is lacking, randomized clinical trials and 2 prospective cohort studies indicate positive effects in overall hair quality, improvement in total hair count, and increased hair density in those men ingesting SP.  There were no serious adverse events.

The question of the week was prepared by Donna Seger, MD

I am interested in any questions you would like answered in the Question of the Week. Please email me with any suggestion at donna.seger@vumc.org.


Donna Seger, MD

Executive Director

Tennessee Poison Center www.tnpoisoncenter.org

Poison Help Hotline: 1-800-222-1222