Saw palmetto appears ineffective for easing UT symptoms associated with BPH

Saw palmetto fruit extract has no effect on lower urinary tract (UT) symptoms, regardless of dose, a study published in The Journal of the American Medical Association found.

The study looked at the effect of saw palmetto extract (Serenoa repens, from saw palmetto berries) at up to 3 times the standard dose on lower UT symptoms attributed to benign prostatic hyperplasia (BPH).

Investigators conducted a double-blind, multicenter, placebo-controlled randomized trial at 11 North American clinical sites between June 5, 2008, and October 10, 2010. Participants included 369 men aged 45 years or older, with a peak urinary flow rate of at least 4 mL/s and an American Urological Association Symptom Index (AUASI) score of between 8 and 24 at 2 screening visits. The men were randomly assigned to receive 1, 2, and then 3 chocolate-colored gelcaps (320 mg/d) containing a standardized saw palmetto fruit extract with dose escalations at 24 and 48 weeks, or placebo.

The primary outcome measure was the change in AUASI score from baseline to 72 weeks, and investigators noted the mean scores decreased a mean of 2.20 points with saw palmetto extract and 2.99 points with placebo, a group mean difference of 0.79 points favored placebo (upper bound of the 1-sided 95% CI most favorable to saw palmetto extract was 1.77 points, 1-sided P=.91). A mixed models repeated measures analysis demonstrated no greater improvement with saw palmetto extract versus placebo (P=.22). The dose response analysis also showed no greater improvement at any dose level with saw palmetto extract versus placebo.

Saw palmetto extract had no greater effect than placebo on any of the secondary outcome measures, which included measures of urinary bother, nocturia, peak uroflow, postvoid residual volume, prostate-specific antigen level, participants' global assessments, and indices of sexual function, continence, sleep quality, and prostatitis symptoms. The secondary outcome: no clearly attributable adverse effects were identified.

“We studied only 1 extract and because the potential active ingredients and mechanisms are unknown, our findings may not be generalizable. Nevertheless, a recent series of negative trials using different saw palmetto extract preparations makes it increasingly unlikely a dose of some preparation will be identified that is better than placebo,” the authors wrote.