Maca (L. meyenii) for improving sexual function: a systematic review

Byung-Cheul Shin; Myeong Soo Lee; Eun Jin Yang; Hyun-Suk Lim; Edzard Ernst

doi:10.1186/1472-6882-10-44

Therapeutics Supplements and Botanicals

Maca (L. meyenii) for improving sexual function: a systematic review

Shin BC, Lee MS, Yang EJ, Lim HS, Ernst E

Published August 6, 2010 BMC complementary and alternative medicine, 10, 44

DOI 10.1186/1472-6882-10-44 PMID 20691074 PMC PMC2928177

RRM Academy Synopsis

Maca has limited trial evidence for improving sexual function

A 2010 systematic review of four small placebo-controlled trials with 131 participants found limited evidence that maca improves sexual function. Three trials suggested a benefit, and a trial in male cyclists showed no effect. The authors judged the evidence too thin for firm conclusions.

Key Findings

The search of 17 databases identified 88 articles, and 84 were excluded. Four randomized clinical trials with 131 participants in total met the inclusion criteria.
In 50 men with mild erectile dysfunction, maca scored higher than placebo on the IIEF-5 questionnaire (mean difference 1.10, 95% CI 0.61 to 1.59, P < 0.001).
In 16 healthy postmenopausal women, maca showed a positive effect on sexual function against placebo on the Greene Climacteric Scale (mean difference 0.70, 95% CI 0.08 to 1.32, P < 0.05).
In 8 male cyclists, maca produced no significant change in sexual desire against placebo (mean difference 6.38, 95% CI -11.32 to 24.08).
None of the four trials reported a method of sequence generation or used allocation concealment, and none assessed the adverse effects of maca.

Interpretation

The paper is a systematic review of randomized, double-blind, placebo-controlled trials. The trials differed too much in statistics and clinical features to pool. They studied men with mild erectile dysfunction, healthy men, healthy postmenopausal women and male cyclists, so each result applies to its own group. Sample sizes ranged from 8 to 57. The authors note that weak sequence generation and allocation concealment tend to inflate treatment effects.

RRM Context

Andean communities have long used maca to support fertility, and animal studies point to effects on sperm production. The four trials measured sexual function and desire, and the review reports no data on sperm or conception. Restorative reproductive medicine seeks the cause of sexual dysfunction and trouble getting pregnant in both partners.

Our editorial summary of this paper, not the article's abstract.

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.

Conclusion

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.

Topics

Therapeutics › Supplements and Botanicals › Herbal and Botanical Products · Sexual Health › Sexual Function › Libido and Desire

Byung-Cheul Shin, Myeong Soo Lee, Eun Jin Yang, Hyun-Suk Lim, Edzard Ernst

B Shin, M Lee, E Yang, H Lim, E Ernst

PMID 20691074 20691074 DOI 10.1186/1472-6882-10-44 10.1186/1472-6882-10-44 Shin et al. 2010, Shin 2010

Maca (L. meyenii) for improving sexual function: a systematic review

Maca has limited trial evidence for improving sexual function

Key Findings

Interpretation

RRM Context

Abstract

Topics

By this author

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