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This fact sheet provides basic information about saw palmetto—common names, what the science says, potential side effects and cautions, and resources for more information.
Saw palmetto is a small palm tree native to the eastern United States. Its fruit was used medicinally by the Seminole Tribe of Florida. Saw palmetto is used as a traditional or folk remedy for urinary symptoms associated with an enlarged prostate gland (also called benign prostatic hyperplasia, or BPH), as well as for chronic pelvic pain, bladder disorders, decreased sex drive, hair loss, hormone imbalances, and prostate cancer.
The ripe fruit of saw palmetto is used in several forms, including ground and dried fruit or whole berries. It is available as liquid extracts, tablets, capsules, and as an infusion or a tea.
What the Science Says
- Several small studies suggest that saw palmetto may be effective for treating BPH symptoms. However, a 2011 NCCIH-cofunded study in 369 older men demonstrated that saw palmetto extract administered at up to three times the standard daily dose (320 mg) did not reduce the urinary symptoms associated with BPH more than placebo. In addition, a 2009 review of the research concluded that saw palmetto has not been shown to be more effective than placebo for this use.
- In 2006, an NIH-funded study of 225 men with moderate-to-severe BPH found no improvement with 320 mg of saw palmetto daily for 1 year versus placebo.
- There is not enough scientific evidence to support the use of saw palmetto for reducing the size of an enlarged prostate or for any other conditions.
- Saw palmetto does not appear to affect readings of prostate-specific antigen (PSA) levels. PSA is a protein produced by cells in the prostate. The PSA test is used to screen for prostate cancer and to monitor patients who have had prostate cancer.
- An NCCIH-funded study is looking at the effects of saw palmetto extract on prostate cancer cells.
Side Effects and Cautions
- Saw palmetto appears to be well tolerated by most users. It may cause mild side effects, including stomach discomfort.
- Tell all your health care providers about any complementary health approaches you use. Give them a full picture of what you do to manage your health. This will help ensure coordinated and safe care.
For More Information
The NCCIH Clearinghouse provides information on NCCIH and complementary and integrative health approaches, including publications and searches of Federal databases of scientific and medical literature. The Clearinghouse does not provide medical advice, treatment recommendations, or referrals to practitioners.
A service of the National Library of Medicine (NLM), PubMed® contains publication information and (in most cases) brief summaries of articles from scientific and medical journals.
Office of Dietary Supplements (ODS), National Institutes of Health (NIH)
ODS seeks to strengthen knowledge and understanding of dietary supplements by evaluating scientific information, supporting research, sharing research results, and educating the public. Its resources include publications (such as Dietary Supplements: What You Need to Know), fact sheets on a variety of specific supplement ingredients and products (such as vitamin D and multivitamin/mineral supplements), and the PubMed Dietary Supplement Subset.
NIH National Library of Medicine's MedlinePlus
- Barry MJ, Meleth S, Lee JY, et al. Effect of increasing doses of saw palmetto extract on lower urinary tract symptoms: a randomized trial. JAMA. 2011;306(12):1344–1351.
- Bent S, Kane C, Shinohara K, et al. Saw palmetto for benign prostatic hyperplasia. New England Journal of Medicine. 2006;354(6):557–566.
- Croom EM Jr. Saw palmetto (Serenoa repens). In: Coates P, Blackman M, Cragg G, et al., eds. Encyclopedia of Dietary Supplements. New York, NY: Marcel Dekker; 2005;635-644.
- National Cancer Institute. The Prostate-Specific Antigen (PSA) Test: Questions and Answers. National Cancer Institute Web site. Accessed at www.cancer.gov/cancertopics/factsheet/Detection/PSA on June 3, 2010.
- Saw palmetto. Natural Medicines Comprehensive Database Web site. Accessed at www.naturaldatabase.com on August 7, 2009.
- Saw palmetto (Serenoa repens [Bartran] Small). Natural Standard Database Web site. Accessed at www.naturalstandard.com on August 4, 2009.
- Saw palmetto berry. In: Blumenthal M, Goldberg A, Brinckman J, eds. Herbal Medicine: Expanded Commission E Monographs. Newton, MA: Lippincott Williams & Wilkins; 2000:335–340.
- Tacklind J, MacDonald R, Rutks I, et al. Serenoa repens for benign prostatic hyperplasia. Cochrane Database of Systematic Reviews. 2009;CD001423.
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