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April 2013

Researchers Evaluate Safety of Saw Palmetto Extract

Saw palmetto extract may be safe when used to treat lower urinary tract symptoms caused by benign prostatic hyperplasia (BPH) at high doses for 18 months, a study reports.

Saw palmetto (Serenoa repensSerenoa serrulata) is used popularly in Europe to treat symptoms of enlarged prostate. Although it is not considered the standard of care in the United States, it is the most popular herbal treatment for this condition. More than two million American men use saw palmetto for enlarged prostate, and it is commonly recommended as an alternative treatment by the U.S. Food and Drug Administration (FDA).

BPH is a normal, gradual enlargement of the prostate caused by hormonal fluctuations. BPH usually beings in middle age and does not lead to cancer. BPH does not generally cause pain, but discomfort (a feeling of pressure) in the groin area is generally found. As the prostate enlarges, it presses against the urethra and interferes with urination. At the same time, the bladder wall becomes thicker and irritated and begins to contract, even when it contains small amounts of urine, which causes more frequent urination. And, as the bladder continues to weaken, it may not empty completely leaving some urine behind. Blocking or narrowing of the urethra by the prostate and partial emptying of the bladder cause many of the problems associated with BPH.

In the current study, researchers set out to determine the safety of saw palmetto extract when used over an extended period. They included information from 357 people who had participated in the Complementary and Alternative Medicine for Urological Symptoms (CAMUS) trial. The subjects were randomized to 320, 640, or 960 milligrams of saw palmetto extract or a placebo daily at six-month intervals for a total of 18 months. The research team assessed the participants' vital signs, blood, urine, and any side effects experienced.

The scientists found that significant differences between the treatment and placebo groups were lacking in terms of serious or non-serious side effects, changes in vital signs, or prostate exam results. They reported that evidence of side effects related to dosing was also lacking.

The team concluded that the saw palmetto extract used in the CAMUS trial may be safe at doses of three times the usual clinical dose over 18 months. However, more research is needed to confirm these findings.

Many studies report that saw palmetto may be as effective as the hormonal agent finasteride (Proscar®) and may cause fewer side effects when used to treat bladder problems. Most research has focused on the saw palmetto product Permixon®. However, results are still mixed, and further research is needed. Saw palmetto has also been used for low sperm count, low sex drive, hair loss, bronchitis, diabetes, inflammation, migraine, and prostate cancer, although there is limited evidence supporting its effectiveness for these conditions.

Other integrative therapies that have been used for BPH or related urinary conditions include pygeum, which is supported by strong scientific evidence, and beta-sitosterol and selenium, which are supported by good evidence.

For more information about saw palmetto, please visit Natural Standard's Foods, Herbs & Supplements Database.


  1. Avins AL, Lee JY, Meyers CM, et al. Safety and Toxicity of Saw Palmetto in the CAMUS Trial. J Urol. 2013 Apr;189(4):1415-20. doi: 10.1016/j.juro.2012.10.002. Epub 2012 Oct 9. 
  2. Natural Standard: The Authority on Integrative Medicine. 

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