Question
What are the benefits of saw palmetto for men?
Answer
Saw palmetto is the common name for a type of plant (a small palm) from America. Its scientific name is Serenoa repens (it has also been known as Serenoa serrulate and Sabal serrulate). Any of these names might be used on products that are sold as natural treatments for hair loss (androgenic alopecia) or lower urinary tract symptoms due to prostate enlargement (benign prostatic hyperplasia or BPH).
Saw palmetto is believed to work by decreasing the effects of androgens (testosterone and its metabolite, dihydrotestosterone) in prostate cells and hair follicles. Scientific evidence to support these claims is lacking though.
The Cochrane Library is one of the best sources of health evidence in the world and is accessible to anyone in Australia. A review of evidence published by the Cochrane Library last year concludes that saw palmetto has little if any effect on lower urinary tract symptoms in the short or long term. It doesn’t seem to cause any problems in the short term but there’s some uncertainty about safety in the long term.
When it comes to the benefits of saw palmetto for hair loss, there is no Cochrane review because there is no good quality evidence. Some small studies suggest saw palmetto (taken either by mouth or used in a lotion and shampoo) can increase hair growth, but not to the same extent as finasteride (a medication taken as a tablet prescribed by your doctor, but with worrying possible side effects). Basically, there’s no proven effect of saw palmetto on preventing hair loss or causing hair regrowth.
So, in answer to the question, “What are the benefits of saw palmetto?”, the answer is “maybe none”.
Tim Moss
Biomedical research scientist
Associate Professor Tim Moss has PhD in physiology and more than 20 years’ experience as a biomedical research scientist. Tim stepped away from his successful academic career at the end of 2019, to apply his skills in turning complicated scientific and medical knowledge into information that all people can use to improve their health and wellbeing. Tim has written for crikey.com and Scientific American’s Observations blog, which is far more interesting than his authorship of over 150 academic publications. He has studied science communication at the Alan Alda Centre for Communicating Science in New York, and at the Department of Biological Engineering Communication Lab at MIT in Boston.
