Saw palmetto, also known as Serenoa repens or Serenoa serrulata or Sabal serrulata, is a dwarf palm tree that is native to the southeastern United States.1 Saw palmetto was traditionally used by the Native Americans to treat many conditions such as coughs and disorders associated with the male and female reproductive organs. Currently, saw palmetto is used as a dietary supplement for benign prostatic hyperplasia, chronic pelvic pain, migraine, and hair loss.1,2
What is benign prostatic hyperplasia?
Benign prostatic hyperplasia (BPH) is a non-cancerous enlargement of the prostate gland.3 It is a common cause of lower urinary tract symptoms in men age 50 and older. A prostate is a part of the male reproductive system. It produces prostate fluid that is important for a man’s fertility. The prostate gland is located around the urethra, right below the bladder.3 A man goes through two prostate growth phases in his life. The first phase occurs during puberty, in which the prostate doubles in size. The second phase starts at age 25 and continues during most of his life.3,4 BPH occurs during the second prostate growth phase.
As the prostate grows in size, the prostate gland presses against the urethra. Over time, the bladder becomes weak and loses its ability to empty completely.3 Symptoms of BPH include urinary retention, urinary frequency, urinary urgency, urinary incontinence, and problems with urine stream.4 Prescription medications used for the treatment of BPH include tamsulosin, doxazosin, finasteride, dutasteride, and tadalafil.3
How does saw palmetto improve symptoms of benign prostatic hyperplasia?
It is not completely understood how saw palmetto exerts its effects in the body. Saw palmetto is thought to decrease the size of the inner lining that puts pressure on the urethra.2
Studies have been done to investigate whether saw palmetto provides benefits to people with BPH. A 2006 double-blind trial evaluated men over 49 years old who had moderate-severe symptoms of BPH.5 The participants were randomly assigned to saw palmetto extract 160 mg twice daily for one year or placebo daily for one year. The changes in maximum urinary flow rate, prostate size, residual urinary volume after voiding, and quality of life were very similar in saw palmetto and placebo groups.
A 2011 randomized controlled trial investigated the effect of increasing doses of saw palmetto extract on lower urinary tract symptoms.6 The participants received either saw palmetto extract 320 mg daily, 640 mg daily, then 960 mg daily or placebo daily, with dose increases at weeks 24 and 48. Compared to placebo, saw palmetto did not significantly improve nocturia, peak urinary flow, post-voidal residual volume, urinary continence, and sleep quality.
A 2015 open-label study was conducted to determine how safe and efficacious saw palmetto extract was in treating BPH.7 The participants were given saw palmetto extract 160 mg daily for 12 weeks. In comparison to the baseline, urinary flow rate, post-void residual urine, and quality of life improved significantly at week 12.
A 2016 and 2018 systematic review and meta-analysis looked at 15 randomized controlled trials and 12 observational studies on efficacy and safety of extract of Serenoa repens (Permixon) in the treatment of lower urinary tract symptoms due to BPH.8,9 The participants were received Permixon or either placebo, tamsulosin, or finasteride. The meta-analysis concluded that Permixon was significantly more effective at improving urinary flow and reducing nighttime urination, compared to placebo. Permixon also appeared to be as efficacious as tamsulosin and finasteride in relieving the lower urinary tract symptoms. In addition, unlike tamsulosin and finasteride, Permixon had minimal impact on sexual function.
Lastly, a 2019 randomized controlled trial investigated the efficacy and safety of saw palmetto extract in patients with BPH.10 The participants were randomly assigned to saw palmetto extract 320 mg daily for 24 weeks or placebo daily for 24 weeks. Compared to placebo, saw palmetto significantly improved peak urinary flow, voiding symptoms, quality of life, and sexual function.
How do you take saw palmetto?
Saw palmetto dietary supplement is made from the dark berries produced by the saw palmetto tree.11 The supplement is available as capsules, tablets, and oily extracts.11 Saw palmetto is not approved as a drug by the Food and Drug Administration (FDA). It can be difficult to determine how much saw palmetto to consume as there are no official recommended dosages. It is recommended to start with a low dosage and increase slowly until the desired effect is reached. And, before using saw palmetto, have a discussion with your doctor to make sure it is appropriate to use.
Safety of saw palmetto
Saw palmetto is safe and generally well tolerated. Most common side effects are dizziness, headache, nausea, vomiting, constipation, and diarrhea.1,2 There have been two case reports of liver damage and one case report of pancreas damage in people consuming saw palmetto products.2 However, it was not clear whether the liver damage or pancreas damage was due to saw palmetto alone. The safety of saw palmetto during pregnancy and lactation has not been extensively studied.2
Saw palmetto is not known to have major interactions with any medication. Saw palmetto has a moderate interaction with estrogen-containing medications such as oral contraceptives. It may reduce the levels of estrogen in the body, resulting in the decreased effectiveness of oral contraceptives.2 Saw palmetto also slows blood clotting. Therefore, taking saw palmetto and anticoagulants (e.g. warfarin, Eliquis, Xarelto, heparin, Lovenox) or antiplatelets (e.g. aspirin, Plavix) may increase the risk of bleeding and bruising.2
Saw palmetto is currently used as a dietary supplement for benign prostatic hyperplasia. It is suggested that saw palmetto works by shrinking the inner lining that puts pressure on the urethra. Studies on the efficacy of saw palmetto for benign prostatic hyperplasia showed mixed results. Before using saw palmetto for benign prostatic hyperplasia, please consult your doctor to make sure it is safe and appropriate for you.
- “Saw palmetto.” National Center for Complementary and Integrative Health. https://www.nccih.nih.gov/health/saw-palmetto. May 2020. Accessed Oct. 20, 2020.
- “Saw palmetto.” WebMD. https://www.webmd.com/vitamins/ai/ingredientmono-971/saw-palmetto. Accessed Oct. 20, 2020.
- “Prostate Enlargement (Benign Prostatic Hyperplasia).” National Institute of Diabetes and Digestive and Kidney Diseases. https://www.niddk.nih.gov/health-information/urologic-diseases/prostate-problems/prostate-enlargement-benign-prostatic-hyperplasia. Sept. 2014. Accessed Oct. 20, 2020.
- “Benign Prostatic Hyperplasia (BPH).” Johns Hopkins Medicine. https://www.hopkinsmedicine.org/health/conditions-and-diseases/benign-prostatic-hyperplasia-bph. Accessed Oct. 20, 2020.
- Bent, Stephen et al. “Saw palmetto for benign prostatic hyperplasia.” The New England journal of medicine 354,6 (2006): 557-66. doi:10.1056/NEJMoa053085
- Barry, Michael J et al. “Effect of increasing doses of saw palmetto extract on lower urinary tract symptoms: a randomized trial.” JAMA 306,12 (2011): 1344-51. doi:10.1001/jama.2011.1364
- Ju, Xiao-bing et al. Zhonghua nan ke xue = National journal of andrology 21,12 (2015): 1098-101.
- Novara, Giacomo et al. “Efficacy and Safety of Hexanic Lipidosterolic Extract of Serenoa repens (Permixon) in the Treatment of Lower Urinary Tract Symptoms Due to Benign Prostatic Hyperplasia: Systematic Review and Meta-analysis of Randomized Controlled Trials.” European urology focus 2,5 (2016): 553-561. doi:10.1016/j.euf.2016.04.002
- Vela-Navarrete, Remigio et al. “Efficacy and safety of a hexanic extract of Serenoa repens (Permixon®) for the treatment of lower urinary tract symptoms associated with benign prostatic hyperplasia (LUTS/BPH): systematic review and meta-analysis of randomised controlled trials and observational studies.” BJU international 122,6 (2018): 1049-1065. doi:10.1111/bju.14362
- Ye, Zhangqun et al. “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 (2019): 172-179. doi:10.1016/j.urology.2019.02.030
- “What is Saw Palmetto? Prostate Health and Other Uses.” Healthline. https://www.healthline.com/nutrition/saw-palmetto. April 12, 2019. Accessed Oct. 20, 2020.