Saw palmetto doesn't ease lower urinary tract symptoms in men

Saw palmetto extract, even up to three times the standard daily dose, had no more effect on lower urinary tract symptoms in men than placebo, a new trial has found.

Researchers performed a randomized, double-blind, multicenter, placebo-controlled trial at 11 clinical sites in North America between June 5, 2008 and Oct. 10, 2010 to examine whether increasing doses of saw palmetto extract affected lower urinary tract symptoms attributed to benign prostatic hyperplasia (BPH). Participants were male volunteers who were at least 45 years or age with a peak uroflow rate of 4 mL/s or greater and an American Urological Association Symptom Index (AUASI) score of 8 to 24 at two screening visits. The AUASI contains seven items for self-assessed frequency of lower urinary tract symptoms, with a score range of 0 to 35.

The study's main outcome measure was the change in AUASI score from baseline to 72 weeks. Secondary outcome measures were urinary bother, nocturia, peak uroflow, postvoid residual volume, prostate-specific antigen level, and study participants' global assessments, along with indices of sexual function, sleep quality, prostatitis symptoms and continence. The study results were published in the Sept. 28 Journal of the American Medical Association.

A total of 357 men were randomly assigned to receive gelcaps containing 320 mg of saw palmetto (n=176) or placebo (n=181) and were included in the modified intention-to-treat analysis. Participants' mean age was 61 years, and their mean baseline AUASI score was 14.6 points. The initial dose of the study drug was one gelcap per day, increasing to two gelcaps per day at 24 weeks and three gelcaps per day at 48 weeks. Overall, mean AUASI scores decreased by 2.20 points in the saw palmetto group (95% CI, 3.04 to 0.36 points) and by 2.99 points in the placebo group (95% CI, 3.81 to 2.17 points) between baseline and 72 weeks. The mean difference for change in AUASI score from baseline to 72 weeks was 0.79 point in favor of placebo. No secondary outcome measure improved with saw palmetto compared to placebo. No participants reported adverse effects that could be clearly attributed to the study drug.

The authors noted that their study tested only one preparation of saw palmetto extract and that some of the study participants may have had lower urinary tract symptoms for reasons other than BPH. However, they concluded that saw palmetto extract was no better than placebo for any of the outcomes studied, even at amounts up to three times the standard daily dose.