Saw Palmetto Extract: Ineffective for Enlarged Prostate Symptoms

A study published in the Sept. 28, 2011, Journal of the American Medical Association confirmed that the popular herbal supplement saw palmetto extract is no different than an inactive placebo in reducing the symptoms of an enlarged prostate gland, also called benign prostatic hyperplasia (BPH), in men.

The study’s authors observed that, though saw palmetto extract is widely used to treat the symptoms of BPH, the results of recent gold-standard, randomized, clinical trials have questioned the herb’s efficacy in the standard dose of 320 milligrams (mg) per day. This study would determine if increasing the standard daily dose of saw palmetto would improve BPH symptoms compared to use with a placebo. Accordingly, the dose was doubled (to 640 mg at 24 weeks) and then tripled (to 960 mg at 48 weeks and until the trial’s end at 72 weeks).

The U.S. National Institutes of Health (NIH) and the National Center for Complementary and Alternative Medicine (NCCAM) funded the research. A German manufacturer donated the saw palmetto extract capsules and a matching placebo.

Study participants included 369 men aged 45 years or older with BPH symptoms classified as moderate to severe. A standard rating scale called the American Urological Association Symptom Index (AUASI) was used to measure the effects of saw palmetto and a placebo on BPH symptoms. The AUASI index uses a 35-point scale, with 1-7 points being mild, 8-19 as moderate and 20-35 as severe symptoms from an enlarged prostate. Subjects had to have a score between 8 and 24 at two screening visits to be eligible.

At the end of the 72-week study, the placebo group showed a greater drop in the AUASI (i.e., improvement in symptoms) than the group taking the saw palmetto (see Table 1). The difference was 0.79 points favoring the placebo but was not statistically significant. On average, the men in the study began with moderate symptoms of BPH and ended with moderate symptoms of BPH.

Table 1. Saw Palmetto Extract Study Results

BPH symptoms and approved drugs

Common symptoms of BPH include:

• urinary retention
• incomplete emptying of bladder
• the need to urinate two or more times per night
• pain with urination or bloody urine (may indicate infection)
• slowed or delayed start of the urinary stream
• the need to strain to urinate
• strong and sudden urge to urinate
• weak urine stream

The Food and Drug Administration (FDA) has approved nine drugs to treat symptoms of BPH (see Table 2). In the October 2011 Worst Pills, Best Pills News, Public Citizen listed the 5-alpha reductase inhibitors as “Do Not Use” drugs because they may increase the risk of aggressive prostate cancer tumors.

Table 2. FDA-Approved Drugs for Treating BPH-Symptoms

* Do Not Use
**Limited Use (offers limited benefit or benefits certain people or conditions)

In the April 2006 Worst Pills, Best Pills News, we wrote about another gold-standard clinical study funded by NIH and NCCAM that compared saw palmetto to a placebo to treat the symptoms of BPH. This study, published in the Feb. 9, 2006, New England Journal of Medicine, also showed that saw palmetto was no more effective than an inactive placebo in treating BPH symptoms.

Drugs causing BPH symptoms

An inability to urinate is a common symptom of BPH; however, some drugs can cause urinary retention (see selected list in Table 3). Before you begin any treatment for BPH symptoms, make sure those symptoms are not drug-induced.

Table 3. Drugs That Can Cause Urinary Retention

* Do Not Use
**Limited Use (offers limited benefit or benefits certain people or conditions)

FDA regulations

Thousands of herbs and supplements have been marketed without scientific evidence that they are either safe or of therapeutic benefit for any purpose since Congress deregulated the U.S. dietary supplement industry in 1994 with the passage of the Dietary Supplement Health and Education Act.

In 1998, Congress established the taxpayer-funded NCCAM to conduct high-quality research on com-plementary and alternative medicine. To date, NCCAM-funded research has been unable to show that any complementary, alternative medicine does what its proponents claim. This includes saw palmetto extract.

What You Can Do

Do not use saw palmetto extract if you have symptoms of BPH. It has not been shown effective in high-quality research studies.

You should consult your physician before you begin treatment for BPH symptoms. This consultation should include a review of the drugs you are taking and an exploration of the possibility that one of these drugs could be causing your symptoms.

Consumers may report serious adverse events with drugs or product quality problems to the FDA’s MedWatch Adverse Event Reporting program online or by regular mail, fax or phone.

• Online: www.accessdata.fda.gov/scripts/medwatch/medwatch-online.htm
• Regular mail: Use postage-paid, pre-addressed FDA form 3500 and mail to MedWatch, 5600 Fishers Lane, Rockville, MD 20852-9787
• Fax: (800) FDA-0178
• Phone: (800) FDA-1088