Saw palmetto: uses, benefits, and side effects

There may be times you look in the mirror and realize that your hair isn’t as thick as it once was. If you’ve been researching possible remedies, you might have come across something called saw palmetto. 

Saw palmetto extract is an herbal dietary supplement available over-the-counter at most pharmacies. Healthcare professionals have used saw palmetto for many years to treat benign prostatic hyperplasia (BPH), a common condition characterized by an enlarged prostate (Kwon, 2019). 

Scientists have also been exploring saw palmetto as a treatment for hair loss. Here’s more on the different uses for this supplement and whether it can really stave off the loss of those luscious locks. 

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Nobody fully knows how saw palmetto works yet, but it does seem to block hormones called androgens.

High levels of androgens are associated with BPH. BPH is a common condition that causes symptoms like frequent urination, difficulty passing urine, and dribbling of urine. It affects about 70% of men between 60-69 years of age (Wei, 2005). 

Because saw palmetto helps lower androgens, healthcare providers have been recommending the supplement to alleviate BPH symptoms. But as we’ll explore below, that’s not the only use for saw palmetto.    

So why do people take saw palmetto supplements? Let’s explore some of its uses and the evidence behind each one.

Saw palmetto for hair loss

Hair loss and thinning are very common. Androgenic alopecia is a type of hair loss related to high levels of androgens including dihydrotestosterone, or DHT. 

Some hair loss treatments work by blocking DHT, and researchers are searching for other treatments that have this effect––including herbal dietary supplements like saw palmetto. 

Several small studies suggest that saw palmetto may help treat hair loss. For example, doctors in one study gave one group of men with hair loss finasteride (also known as Propecia) and another group saw palmetto supplements.

Over the course of two years, participants saw the most improvements while taking finasteride, but many who took saw palmetto also reported significant improvement––without any of the side effects seen with the medicated group (Rossi, 2012).   

Saw palmetto for BPH

BPH often causes lower urinary tract symptoms including weak urine flow, leaking urine during sleep, and pain or dribbling during urination. 

Researchers in multiple studies have found that saw palmetto isn’t necessarily better at treating BPH than prescription medications, but unlike prescription drugs, it didn’t cause side effects like erectile dysfunction (ED) (Cai, 2020). In fact, some studies suggest that it may improve ED in people with enlarged prostates (Suter, 2013).  

In another study, scientists added a plant substance called beta-sitosterol to saw palmetto extract. Those who took this combination saw a more drastic improvement in their prostate enlargement than the people who took saw palmetto extract alone (Sudeep, 2020).   

Testosterone and saw palmetto

You may have heard of testosterone boosters. Testosterone is a hormone that affects many activities in the male body, including sex drive. Some people take saw palmetto to increase their testosterone levels. Unfortunately, clinical trials have found little evidence that this works (Balasubramanian, 2019).  

Saw palmetto for polycystic ovary syndrome

People with polycystic ovary syndrome, or PCOS, have high levels of androgens. High androgen levels can cause hair growth on the face and body (a condition known as hirsutism), as well as hair loss on the head.

Since saw palmetto seems to interfere with androgens, it may help treat some of these symptoms. However, there is no current evidence supporting this use (El-Sheikh, 1988; Grant, 2012).  

People who take saw palmetto don’t usually experience side effects. If they do, the effects are mild and may include upset stomach, nausea, or diarrhea. 

Saw palmetto might also lower PSA levels. PSA is a chemical made by the prostate. Healthcare professionals use this level to test for diseases like prostate cancer and saw palmetto can sometimes interfere with the results (Murugusundram, 2009).

A small number of people developed liver problems while taking saw palmetto, but it’s not known if saw palmetto was the cause (Zheng, 2016).

Since saw palmetto may affect androgen levels, it could harm a developing fetus or newborn. For this reason, people who are pregnant or breastfeeding should avoid taking saw palmetto (Kalwat, 2019).

Though prescription drugs are more effective in some instances, saw palmetto can have benefits that medication does not. 

For example, saw palmetto doesn’t cause many side effects. It also typically doesn’t interact with other medications, although it is always helpful to check with a healthcare professional first (Asher, 2017).

More and more people today are using herbal supplements to address a variety of health concerns. While saw palmetto is used successfully for prostate symptoms, researchers are still investigating whether it can improve other conditions like hair loss and PCOS. 

Saw palmetto might not be more effective than prescription medication, but it has the bonus of rarely causing side effects and not interacting with other drugs. Your healthcare provider can help you decide if saw palmetto will be safe and helpful for you.

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Current version

September 24, 2021

Written by

Gina Allegretti, MD

Fact checked by

Yael Cooperman, MD

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About the medical reviewer

Yael Cooperman, MD, Ro

Yael Cooperman is a physician and works as a Senior Manager, Medical Content & Education at Ro.