Lepidium meyenii (Maca) is a cultivated root belonging to the brassica family
used in the Andean region for its supposed aphrodisiac properties. We carried
out a double-blind clinical trial on 50 Caucasian men affected by mild erectile
dysfunction (ED), randomised to treatment with Maca dry extract, 2400 mg,
or placebo. The treatment effect on ED and subjective well-being was tested
administrating before and after 12 weeks the International Index of Erectile
Function (IIEF-5) and the Satisfaction Profile (SAT-P). After 12 weeks of treatment,
both Maca- and placebo-treated patients experienced a significant
increase in IIEF-5 score (P < 0.05 for both). However, patients taking Maca
experienced a more significant increase than those taking placebo (1.6 � 1.1
versus 0.5 � 0.6, P < 0.001). Both Maca- and placebo-treated subjects experienced
a significant improvement in psychological performance-related SAT-P
score, but the Maca group higher than that of placebo group (+9 � 6 versus
+6 � 5, P < 0.05). However, only Maca-treated patients experienced a significant
improvement in physical and social performance-related SAT-P score
compared with the baseline (+7 � 6 and +7 � 6, both P < 0.05). In conclusion,
our data support a small but significant effect of Maca supplementation
on subjective perception of general and sexual well-being in adult patients with
mild ED.

We sought to determine whether maca, a Peruvian plant, is effective for selective-serotonin reuptake inhibitor (SSRI)-induced sexual dysfunction. We conducted a double-blind, randomized, parallel group dose-finding pilot study comparing a low-dose (1.5 g/day) to a high-dose (3.0 g/day) maca regimen in 20 remitted depressed outpatients (mean age 36+/-13 years; 17 women) with SSRI-induced sexual dysfunction. The Arizona Sexual Experience Scale (ASEX) and the Massachusetts General Hospital Sexual Function Questionnaire (MGH-SFQ) were used to measure sexual dysfunction. Ten subjects completed the study, and 16 subjects (9 on 3.0 g/day; 7 on 1.5 g/day) were eligible for intent-to-treat (ITT) analyses on the basis of having had at least one postbaseline visit. ITT subjects on 3.0 g/day maca had a significant improvement in ASEX (from 22.8+/-3.8 to 16.9+/-6.2; z=-2.20, P=0.028) and in MGH-SFQ scores (from 24.1+/-1.9 to 17.0+/-5.7; z=-2.39, P=0.017), but subjects on 1.5 g/day maca did not. Libido improved significantly (P<0.05) for the ITT and completer groups based on ASEX item #1, but not by dosing groups. Maca was well tolerated. Maca root may alleviate SSRI-induced sexual dysfunction, and there may be a dose-related effect. Maca may also have a beneficial effect on libido.