Saw Palmetto

Background

• Saw palmetto is a small tree that grows to a height of 6 to 10 feet. It is native to the West Indies and the southeast coast of North America. Its berries have been used for health purposes.
• Saw palmetto is promoted as a dietary supplement for urinary symptoms associated with an enlarged prostate gland (also called benign prostatic hyperplasia or BPH), as well as for male pattern baldness, chronic prostatitis/chronic pelvic pain syndrome (a frequently painful condition involving inflammation of the prostate), and other conditions.

How Much Do We Know?

• Many studies have been conducted on the usefulness of saw palmetto for urinary tract symptoms associated with prostate enlargement in men. We know enough to conclude that saw palmetto is probably not helpful for this purpose.
• There is not enough evidence to determine whether saw palmetto is useful for other health purposes. More studies are needed before definitive conclusions can be made.

What Have We Learned?

• A 2023 review of 27 studies on saw palmetto in men with BPH found that this herb, when administered alone, provides little or no benefit for BPH symptoms. Definite conclusions could not be reached about the effects of combinations of herbs that include saw palmetto.
  • Two clinical trials funded by the National Institutes of Health, both of which evaluated saw palmetto alone, were included in this review. One tested a standard dose of saw palmetto; the other tested increasing doses of saw palmetto, up to three times the usual dose. In both studies, saw palmetto did not improve BPH symptoms.
  • Because it had been suggested that saw palmetto products prepared using hexane extraction might be more effective than those prepared in other ways, the reviewers analyzed studies of these products and studies of other products separately. No difference was found in the effects of the two kinds of products on BPH symptoms.

• A 2022 review of five studies on saw palmetto for chronic prostatitis/chronic pelvic pain syndrome did not find a significant benefit of the herb in patients with this condition. 
• A few small studies have tested saw palmetto, used orally or topically (applied to the scalp), for male-pattern hair loss. The evidence is too limited to allow conclusions to be reached.

What Do We Know About Safety?

• Saw palmetto is well tolerated. It has been used safely in research studies for up to 3 years. Adverse effects are mild and infrequent; they may include digestive symptoms, dizziness, and headache.
• Saw palmetto does not appear to affect readings of prostate-specific antigen (PSA) levels, even when taken in higher-than-usual amounts. PSA is a protein produced by the prostate gland. PSA levels have been used to screen for prostate cancer and are also used to monitor patients who have been diagnosed with prostate cancer
• Saw palmetto may be unsafe for use during pregnancy or while breastfeeding.

Keep in Mind

• Take charge of your health—talk with your health care providers about any complementary health approaches you use. Together, you can make shared, well-informed decisions.
• If you take any type of medicine, talk with your health care provider before using any herbal product; some herbs and medicines interact in harmful ways.
• Federal Regulation of Herbal Products
  • Depending on what’s in them, how they’re intended to be used, and how they’re administered (orally or topically), herbal products are regulated in a variety of ways. Many herbal products intended for oral use are marketed as dietary supplements. The regulatory paths for making and distributing dietary supplements are different than those for drugs.
  • Unlike drugs, dietary supplements are not approved by the U.S. Food and Drug Administration (FDA) before they are sold to the public. When public health concerns arise about the safety of a dietary supplement or an ingredient including an herb, the FDA can take action to protect the public. Manufacturers and distributors of supplements are responsible for evaluating the safety and labeling of their products before marketing to ensure that they meet all regulatory requirements. 

For More Information

• Using Dietary Supplements Wisely
• Know the Science: How Medications and Supplements Can Interact
• Know the Science: How To Make Sense of a Scientific Journal Article

Key References