Serenoa repens and its effects on male sexual function. A systematic review and meta-analysis of clinical trials

Serenoa repens (SR) is a plant used to treat benign prostatic hyperplasia and prostatitis. We know that SR act as a 5α-reductase inhibitor, moreover, several studies have proved that SR has anti-inflammatory and antioxidant properties. There is some belief among patients that SR may negatively impact male sexual function. Such belief is circulating in non-medical social networks and is perhaps maintained by patients as a result of incorrect web surfing. However, it is also possible that SR may exert a "nocebo" effect thus negatively impacting on the general well-being of patients.

The aim of this study is to investigate whether SR is causing negative effects on male sexual function.

To ascertain the effect of SR on male sexual function, we conducted a systematic review and meta-analysis, by performing an electronic database search in accordance with the PRISMA guidelines.

Out of 20 included papers, 8 papers reported comparisons of SR with placebo, and 7 studies reported comparisons of SR with tamsulosin. The standardized mean difference of changes from baseline scores of sexual function was not significantly different between SR and placebo (SMD: 0.43, 95% CI: 0.18 to 1.05; I^2 = 95%). Similarly, no significant mean differences in the Male Sexual Function-4 (MSF-4) test scores were found between SR and tamsulosin (SMD: -0.31, 95% CI: -0.82 to 0.19; I^2 = 90%).

We found no statistically significant differences between negative effects on sexual function in patients treated with SR compared to patients who received placebo. The results of our meta-analysis are similar to those of other systematic reviews. Studies are warranted to ascertain whether any such effects might occur as a result of a nocebo effect.