Randomised, placebo-controlled, double-blind clinical trial of β-sitosterol in patients with benign prostatic hyperplasia

Medical treatments have become available for benign hypertrophy of the prostate, including alpha-receptor blocking agents and 5-alpha-reductase inhibitors. Drugs derived from plants, for which no precise mechanism of action has been described, are widely used for this purpose in Europe. In a randomised, double-blind, placebo-controlled multi-centre study, 200 patients (recruited between April and October 1993) with symptomatic benign prostatic hyperplasia were treated with either 20 mg β-sitosterol (which contains a mixture of phytosterols) three times per day or placebo. Primary end-point was a difference of modified Boyarsky score between treatment groups after 6 months; secondary end-points were changes in International Prostate Symptom Score (IPSS), urine flow, and prostate volume. Modified Boyarsky score decreased significantly with a mean of -6·7 (SD 4·0) points in the β-sitosterol-treated group versus -2·1 (3·2) points in the placebo group p<0·01. There was a decrease in IPSS (-7·4 [3·8] points in the β-sitosterol-treated group vs-2·1 [3·8] points in the placebo group) and changes in urine flow parameters: β-sitosterol treatment resulted in increasing peak flow (15·2 [5·7] mL/s from 9·9 [2·5] mL/s), and decrease of mean residual urinary volume (30·4 [39·9] mL from 65·8 [20·8] mL). These parameters did not change in the placebo group (p<0·01). No relevant reduction of prostatic volume was observed in either group. Significant improvement in symptoms and urinary flow parameters show the effectiveness of β-sitosterol in the treatment of benign prostatic hyperplasia.