Saw Palmetto

Scientific/medical name(s): Serenoa repens
Saw palmetto is a low-growing palm tree found in the West Indies and in coastal regions of the southeastern United States. The tree grows 6 to 10 feet in height and has a crown of large leaves. The berries are used in herbal remedies.

There is some scientific evidence that saw palmetto relieves symptoms associated with benign prostatic hyperplasia (BPH), such as difficult and frequent urination. However, saw palmetto is not an effective treatment for prostate cancer.

How is it promoted for use?
Saw palmetto is not effective as a treatment for prostate cancer, but may aid in relieving some of the symptoms of BPH (an enlarged prostate gland), which include difficult and frequent urination. Chemicals in saw palmetto berries are believed to interfere with the action of prostate hormones that stimulate cell growth.

Saw palmetto is also promoted as a treatment for prostatitis (inflamed prostate gland). Some proponents claim it also increases sex drive and fertility, and can be used to treat low thyroid function, although there is no scientific evidence to support these claims.

What does it involve?
Saw palmetto supplements are available as capsules, tablets, extracts, and tea. There is no standard dosage. In some clinical studies for the treatment of BPH, patients received 320 mg/day, divided into 2 doses.

What is the history behind it?
Native Americans ate the berries of the saw palmetto believing they served as a tonic that nourished the body, stimulated appetite, and promoted weight gain. They also used the herb to treat problems of the urinary tract and genital systems, such as difficulty urinating or frequent nighttime urination. Saw palmetto supplements are very popular in Europe, especially Germany, where physicians often prescribe them for patients with BPH.

What is the evidence?
Some research has found that saw palmetto extract may reduce symptoms of BPH. In 1998, the Journal of the American Medical Association published a review of 18 scientific studies on saw palmetto conducted over the last 30 years which involved more than 3,000 patients. The report concluded that the extract improved urinary symptoms, such as frequent nighttime urination and problems with urine flow. The improvements from using palmetto extract were similar to those seen in men who took the prescription drug finasteride for BPH. Saw palmetto also caused fewer and milder side effects than finasteride. Finasteride appears to reduce the size of the prostate, but it is still not clear whether saw palmetto causes the prostate to shrink.

Most of the studies using saw palmetto have included small numbers of patients, lasted an average of only 9 weeks, and varied in their design. Also, different dosages and forms of saw palmetto were used, which makes it difficult to establish a standard preparation. More research is needed to determine saw palmetto’s long-term effectiveness and ability to prevent complications from BPH.

It is important to note that BPH is not cancer, and there is no published scientific evidence that saw palmetto has any value in the treatment of prostate cancer.

Are there any possible problems or complications?
The long-term effects and safety of saw palmetto are unknown. Side effects are not common, but may include headache, nausea, vomiting, upset stomach, dizziness, constipation or diarrhea, difficulty sleeping, fatigue, and in rare instances, heart pain. Men who have symptoms of BPH, which include difficult, frequent, or urgent urination, should see a physician as soon as possible, rather than treating themselves with saw palmetto. Similar symptoms can also result from prostate cancer, and self-treatment with saw palmetto may delay diagnosis and treatment of cancer.

It is not known if saw palmetto interferes with the measurement of prostate-specific antigen (PSA), which is a protein made by prostate cells used to determine the presence and extent of prostate cancer. Researchers have not yet thoroughly studied the effects of saw palmetto on blood PSA levels or determined whether saw palmetto interferes with accuracy of the PSA test. Since saw palmetto affects testosterone metabolism in the same way as finasteride, some physicians recommend that men also have a baseline PSA test and digital rectal exam before starting treatment with saw palmetto.

Fetrow CW, Avila JR. Professional’s Handbook of Complementary and Alternative Medicines. Springhouse, Pa: Springhouse Corp; 1999.

Medical Economics. PDR for Herbal Medicines. Montvale, NJ: Medical Economics Company; 1998.

University of Texas Center for Alternative Medicine Research in Cancer. Saw palmetto summary. Available at: Accessed October 29, 1999.

Wilt TJ, Ishani A, Stark G, MacDonald R, Lau J, Mulrow C. Saw palmetto extracts for treatment of benign prostatic hyperplasia A systematic review. JAMA. 1998;280:1604-1609.

Note: This information was reprinted from the American Cancer Society’s Guide to Complementary and Alternative Methods. Copyright(c)2000, American Cancer Society. This information may not cover all possible claims, uses, actions, precautions, side effects or interactions, is not intended as medical advice, and should not be relied upon as a substitute for consultation with your doctor who is familiar with your medical needs.

Add Comment

Your email address will not be published. Required fields are marked *

Be informed!

Sign up for newsletter