The use of maca (Lepidium meyenii) to improve semen quality: A systematic review.

The aim of this review was to assess the evidence for the effectiveness of maca (Lepidium meyenii) in improving semen quality. We searched 11 databases from their inception to March 2016 and included all clinical trials on the improvement of semen quality parameters in infertile and healthy men, regardless of the study design or the type of maca. The risk of bias for each study was assessed using the Cochrane criteria. The selection of studies, data extraction, and validation were performed independently by the first two authors. Discrepancies were resolved through discussion by the same two authors. Five studies - 3 randomized clinical trials (RCTs) and 2 uncontrolled observational studies (UOSs) - met all of the inclusion criteria. One RCT found favorable effects of maca on sperm mobility in infertile men. The two other RCTs showed positive effects of maca on several semen quality parameters in healthy men. The two UOSs also suggested favorable effects of maca on semen quality. The results of our systematic review provide suggestive evidence for the effectiveness of maca in improving semen quality. However, the total number of trials, the total sample size, and the risk of bias of the included studies prevent the drawing firm conclusions. More rigorous studies are warranted.