Saw palmetto: uses, benefits, and side effects

Yael Cooperman, MD - Contributor Avatar

Reviewed by Yael Cooperman, MD, Ro, 

Written by Gina Allegretti, MD 

Yael Cooperman, MD - Contributor Avatar

Reviewed by Yael Cooperman, MD, Ro, 

Written by Gina Allegretti, MD 

last updated: Sep 24, 2021

3 min read

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. 

Hair loss

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How does saw palmetto work?

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.    

Uses of 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).  

Finasteride Important Safety Information: Read more about serious warnings and safety info.

Side effects of saw palmetto

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).

Benefits of saw palmetto

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.


If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.

  • Asher, G. N., Corbett, A. H., & Hawke, R. L. (2017). Common Herbal Dietary Supplement-Drug Interactions. American Family Physician, 96 (2), 101–107. Retrieved from

  • Balasubramanian, A., Thirumavalavan, N., Srivatsav, A., Yu, J., Lipshultz, L. I., & Pastuszak, A. W. (2019). Testosterone Imposters: An Analysis of Popular Online Testosterone Boosting Supplements. The Journal of Sexual Medicine, 16 (2), 203–212. doi: 10.1016/j.jsxm.2018.12.008. Retrieved from

  • Cai, T., Cui, Y., Yu, S., Li, Q., Zhou, Z., et al. (2020). Comparison of Serenoa repens With Tamsulosin in the Treatment of Benign Prostatic Hyperplasia: A Systematic Review and Meta-Analysis. American Journal of Men's Health, 14 (2). doi: 10.1177/1557988320905407. Retrieved from ​​

  • el-Sheikh, M. M., Dakkak, M. R., & Saddique, A. (1988). The effect of Permixon on androgen receptors. Acta Obstetricia et Gynecologica Scandinavica, 67 (5), 397–399. doi: 10.3109/00016348809004247. Retrieved from

  • Grant, P., & Ramasamy, S. (2012). An update on plant derived anti-androgens. International Journal of Endocrinology and Metabolism, 10 (2), 497–502. doi: 10.5812/ijem.3644. Retrieved from

  • Kalwat, J.I., Ham, J., & Kim, J.C. (2019). The Use of Serenoa Repens (Saw Palmetto) in Hair Care Products. Biomedical Journal of Scientific and Technical Research, 13 , 001-004. Retrieved from

  • Kwon, Y. (2019). Use of saw palmetto (Serenoa repens) extract for benign prostatic hyperplasia. Food Science and Biotechnology, 28 (6), 1599–1606. doi: 10.1007/s10068-019-00605-9. Retrieved from

  • Murugusundram, S. (2009). Serenoa Repens: Does It have Any Role in the Management of Androgenetic Alopecia? Journal of Cutaneous and Aesthetic Surgery, 2 (1), 31–32. doi: 10.4103/0974-2077.53097. Retrieved from

  • Prager, N., Bickett, K., French, N., & Marcovici, G. (2002). A randomized, double-blind, placebo-controlled trial to determine the effectiveness of botanically derived inhibitors of 5-alpha-reductase in the treatment of androgenetic alopecia. Journal of Alternative and Complementary Medicine, 8 (2), 143–152. doi: 10.1089/acm.2002.8.143. Retrieved from

  • Rossi, A., Mari, E., Scarno, M., Garelli, V., Maxia, C., Scali, E., et al. (2012). Comparative effectiveness of finasteride vs Serenoa repens in male androgenetic alopecia: a two-year study. International Journal of Immunopathology and Pharmacology, 25 (4), 1167–1173. doi: 10.1177/039463201202500435. Retrieved from

  • Sudeep, H. V., Thomas, J. V., & Shyamprasad, K. (2020). A double blind, placebo-controlled randomized comparative study on the efficacy of phytosterol-enriched and conventional saw palmetto oil in mitigating benign prostate hyperplasia and androgen deficiency. BMC Urology, 20 (1), 86. doi: 10.1186/s12894-020-00648-9. Retrieved from

  • Suter, A., Saller, R., Riedi, E., & Heinrich, M. (2013). Improving BPH symptoms and sexual dysfunctions with a saw palmetto preparation? Results from a pilot trial. Phytotherapy Research, 27 (2), 218–226. doi: 10.1002/ptr.4696. Retrieved from

  • Wei, J. T., Calhoun, E., & Jacobsen, S. J. (2005). Urologic diseases in America project: benign prostatic hyperplasia. The Journal of Urology, 173 (4), 1256–1261. doi: 10.1097/01.ju.0000155709.37840.fe. Retrieved from

  • Ye, Z., Huang, J., Zhou, L., Chen, S., Wang, Z., Ma, L., et al. (2019). Efficacy and Safety of Serenoa repens Extract Among Patients with Benign Prostatic Hyperplasia in China: A Multicenter, Randomized, Double-blind, Placebo-controlled Trial. Urology, 129, 172–179. doi: 10.1016/j.urology.2019.02.030. Retrieved from

  • Zheng, E., & Navarro, V. (2016). Liver injury due to herbal and dietary supplements: A review of individual ingredients. Clinical Liver Disease, 7 (4), 80–83. doi: 10.1002/cld.541. Retrieved from

How we reviewed this article

Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

Current version

September 24, 2021

Written by

Gina Allegretti, MD

Fact checked by

Yael Cooperman, MD

About the medical reviewer

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