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Original Contribution
September 28, 2011

Effect of Increasing Doses of Saw Palmetto Extract on Lower Urinary Tract Symptoms: A Randomized Trial

Author Affiliations

Author Affiliations: Department of Medicine, Massachusetts General Hospital, Boston (Dr Barry); Division of Preventive Medicine, University of Alabama, Birmingham (Drs Meleth, Williams, and Cantor); Department of Biostatistics, University of Arkansas for Medical Sciences, Little Rock (Dr Lee); Department of Urology, University of Iowa, Iowa City (Dr Kreder); Division of Research, Northern California Kaiser Permanente, Oakland (Dr Avins); Department of Urology, Queen's University, Kingston, Ontario, Canada (Dr Nickel); Department of Urology, University of Texas Southwestern Medical Center, Dallas (Dr Roehrborn); Section of Urologic Oncology, University of Colorado, Denver (Dr Crawford); Section of Urology, Yale University School of Medicine, New Haven, Connecticut (Dr Foster); Department of Urology, Weill Cornell Medical College, New York, New York (Dr Kaplan); Urology Associates, New York University, New York, New York (Dr McCullough); Division of Urologic Surgery, Washington University School of Medicine, St Louis, Missouri (Dr Andriole); Maryland Prostate Center, University of Maryland, Baltimore (Dr Naslund); National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland (Dr Kusek); National Center for Complementary and Alternative Medicine, Bethesda, Maryland (Dr Meyers); National Institutes of Health Office of Dietary Supplements, Bethesda, Maryland (Dr Betz); and Department of Urology, Northwestern University Feinberg School of Medicine, Chicago, Illinois (Dr McVary).

JAMA. 2011;306(12):1344-1351. doi:10.1001/jama.2011.1364

Context Saw palmetto fruit extracts are widely used for treating lower urinary tract symptoms attributed to benign prostatic hyperplasia (BPH); however, recent clinical trials have questioned their efficacy, at least at standard doses (320 mg/d).

Objective To determine the effect of saw palmetto extract (Serenoa repens, from saw palmetto berries) at up to 3 times the standard dose on lower urinary tract symptoms attributed to BPH.

Design, Setting, and Participants A double-blind, multicenter, placebo-controlled randomized trial at 11 North American clinical sites conducted between June 5, 2008, and October 10, 2010, of 369 men aged 45 years or older, with a peak urinary flow rate of at least 4 mL/s, an American Urological Association Symptom Index (AUASI) score of between 8 and 24 at 2 screening visits, and no exclusions.

Interventions One, 2, and then 3 doses (320 mg/d) of saw palmetto extract or placebo, with dose increases at 24 and 48 weeks.

Main Outcome Measures Difference in AUASI score between baseline and 72 weeks. Secondary outcomes 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.

Results Between baseline and 72 weeks, mean AUASI scores decreased from 14.42 to 12.22 points (−2.20 points; 95% CI, −3.04 to −0.36) with saw palmetto extract and from 14.69 to 11.70 points (−2.99 points; 95% CI, −3.81 to −2.17) with placebo. The group mean difference in AUASI score change from baseline to 72 weeks between the saw palmetto extract and placebo groups was 0.79 points favoring placebo (upper bound of the 1-sided 95% CI most favorable to saw palmetto extract was 1.77 points, 1-sided P = .91). Saw palmetto extract was no more effective than placebo for any secondary outcome. No clearly attributable adverse effects were identified.

Conclusion Increasing doses of a saw palmetto fruit extract did not reduce lower urinary tract symptoms more than placebo.

Trial Registration clinicaltrials.gov Identifier: NCT00603304