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Saw Palmetto

Medically Reviewed by Michael W. Smith, MD on May 12, 2021

Saw palmetto, also called the American dwarf palm tree, is a palm plant that grows mostly along the coast of the southeastern United States and can be found as far west as California. It gets its name from its green leaves, which look like the teeth of a saw.

The plant has white flowers that produce yellow berries that turn black when they’re ripe. These berries can be dried to make an herb that’s been used for conditions like prostate issues, urinary tract infections, bladder disorders, hormone imbalances, and hair loss. It’s also thought to boost sex drive and the production of sperm. But research has yet to back up these claims.

Saw Palmetto and Prostate Conditions

Some studies in animals have shown that saw palmetto may help keep tumor cells from growing, raising hopes about its potential as a treatment for prostate cancer. But there’s no proof yet that it can treat the condition or lower your chances of getting it. More research is needed to understand whether it has any effects on prostate cancer.

But there is some evidence that it might help ease the symptoms of benign prostatic hyperplasia (BPH).

A man’s prostate gland, which is about the size of a walnut, helps make seminal fluid (semen). BPH, which is very common among men as they get older, happens when that gland gets larger than it should be. That can start to block the urethra, the tube that carries urine out of a man’s body, and cause trouble with urination, like starting or stopping, peeing too often, or having to pee during the night.

It’s not clear how or why saw palmetto may help with BPH. Some studies show that the supplement might shrink the prostate gland. Other possibilities are that it eases inflammation or keeps your body from changing the hormone testosterone into another hormone called dihydrotestosterone (DHT), which may play a role in BPH.

However it works, many other countries use saw palmetto in treatments for BPH. For example, it’s found in 90% of BPH treatments in Germany and in 50% in Italy.

Forms of Saw Palmetto

The ripe fruit of saw palmetto can be used in several forms, including ground and dried fruit or whole berries. It’s available as a liquid extract, tablets, capsules, and as an infusion or a tea.

Side Effects and Risks

Saw palmetto is considered a dietary supplement or herbal product. It’s generally thought to be safe for adults when you take it as directed. But it can affect the way other supplements or medicines work. It may also have mild side effects like stomach discomfort, headache, dizziness, tender breasts, and a decline in sexual desire.

You shouldn’t take saw palmetto if you take medications for BPH, like finasteride, or certain blood-thinners, like warfarin (Coumadin), clopidogrel (Plavix), or aspirin.

Saw palmetto is not recommended for children, pregnant or nursing women, or women who have had (or who are at higher risk of) hormone-related cancer.

Talk to your doctor before trying saw palmetto, and make sure they know about any other herbs or dietary supplements you take.

WebMD Medical Reference

Sources

SOURCES:

National Center for Complementary and Integrative Health: “Saw Palmetto.”

American Family Physician: “Saw Palmetto for Prostate Disorders.”

Mount Sinai: “Saw Palmetto.”

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Natural Standard Database: "Saw palmetto (Serenoa repens [Bartran] Small)."

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De Smet P. New England Journal of Medicine, 2002; vol 347(25): pp 2046-2056.

National Cancer Institute: "The Prostate-Specific Antigen (PSA) Test: Questions and Answers."

"Saw palmetto berry." In Blumenthal, M, Goldberg, A, Brinckman, J, eds. Herbal Medicine: Expanded Commission E Monographs, Lippincott Williams and Wilkins, 2000.

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Barry, MJ. JAMA, September 2011.

Prostate Cancer Research Institute: “Supplements For Men With Prostate Cancer.”

National Library of Medicine: “Saw Palmetto Supplement Use and Prostate Cancer Risk.”

Prostate Cancer Foundation: “Prostate Gland.”

Medscape: “What Is the Role of Hormones In the Pathophysiology of Benign Prostatic Hyperplasia (BPH)?”

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