title: Maca (L. meyenii) for improving sexual function: a systematic review.
abstract: BACKGROUND
  Maca (Lepidium meyenii) is an Andean plant of the brassica (mustard) family. Preparations from maca root have been reported to improve sexual function. The aim of this review was to assess the clinical evidence for or against the effectiveness of the maca plant as a treatment for sexual dysfunction.
  
  
  METHODS
  We searched 17 databases from their inception to April 2010 and included all randomised clinical trials (RCTs) of any type of maca compared to a placebo for the treatment of healthy people or human patients with sexual dysfunction. The risk of bias for each study was assessed using Cochrane criteria, and statistical pooling of data was performed where possible. The selection of studies, data extraction, and validations were performed independently by two authors. Discrepancies were resolved through discussion by the two authors.
  
  
  RESULTS
  Four RCTs met all the inclusion criteria. Two RCTs suggested a significant positive effect of maca on sexual dysfunction or sexual desire in healthy menopausal women or healthy adult men, respectively, while the other RCT failed to show any effects in healthy cyclists. The further RCT assessed the effects of maca in patients with erectile dysfunction using the International Index of Erectile Dysfunction-5 and showed significant effects.
  
  
  CONCLUSIONS
  The results of our systematic review provide limited evidence for the effectiveness of maca in improving sexual function. However, the total number of trials, the total sample size, and the average methodological quality of the primary studies were too limited to draw firm conclusions. More rigorous studies are warranted.
authors.affiliation: Division of Clinical Medicine, School of Oriental Medicine, Pusan National University, Yangsan, South Korea.
authors.forename: Byung-Cheul
authors.initials: BC
authors.lastname: Shin
authors.forename: Myeong Soo
authors.initials: MS
authors.lastname: Lee
authors.forename: Eun Jin
authors.initials: EJ
authors.lastname: Yang
authors.forename: Hyun-Suk
authors.initials: HS
authors.lastname: Lim
authors.forename: Edzard
authors.initials: E
authors.lastname: Ernst
mesh_terms: D007172:Erectile Dysfunction / Q000188:drug therapy; D005260:Female; D006801:Humans; D029686:Lepidium; D008297:Male; D008593:Menopause; D008517:Phytotherapy; D010936:Plant Extracts / Q000627:therapeutic use*; D012735:Sexual Dysfunction, Physiological / Q000188:drug therapy*
chemical_list: D010936:Plant Extracts