How we rate
“Strong” = several concordant meta-analyses or systematic reviews. “Moderate” = one synthesis, or several controlled trials. “Limited” = early trials only. The rating is about the quality of the studies, not about how useful the supplement is.
Maca
A root from the high plateaus of Peru. It indeed improves sexual desire in several trials — but without affecting testosterone, contrary to what its marketing suggests.
Benefits
- Improves sexual desire in healthy men, starting from the eighth week and without any change in testosterone or oestradiol (1,500 to 3,000 mg per day)
- In 50 men suffering from mild erectile dysfunction, 2,400 mg per day for 12 weeks improves the erectile function score and psychological well-being more than placebo
- In postmenopausal women, reduces anxiety, depression and sexual dysfunction — independently of any estrogenic or androgenic activity (3.5 g per day)
- Mitigates sexual dysfunction caused by SSRI antidepressants, with an effect that increases with dose (3 g per day)
- In 69 infertile men, 2 g per day for 12 weeks increase sperm concentration — without changing its volume, motility or morphology
Precautions
A 90-day safety trial noted a slight increase in transaminases (AST) and diastolic blood pressure in volunteers taking maca alone — something to know before opting for high doses of powder. Another trial in postmenopausal women observes the opposite for blood pressure, a drop in diastolic pressure: the two results do not overlap. Also worth noting: maca does not do what it is most often sold for. Neither testosterone, oestradiol, LH, FSH nor prolactin change with maca in healthy men — the effect on desire therefore operates through something other than hormones. On the sports side, nothing: in ten well-trained basketball players, two weeks at 2 g per day changed nothing regarding jumping, shooting, repeated sprints or the fatigue index, and in eight cyclists the improvement in time trial performance did not exceed that of the placebo. Regarding fertility, the picture is uncertain: one trial sees sperm concentration increase, another measures a 40 % improvement without the difference being significant compared to placebo, and its authors conclude that the data are insufficient. The three available systematic reviews agree on one point: the effects are favourable, but the trials are few and small.
Recommended dosage
Trials use 1.5 to 3.5 g per day, over 8 to 16 weeks. The only trial that monitored the effect week by week sees it appear around the eighth week: nothing should be expected from the first few days.
How to take it
- Tested doses: most often 1.5 to 3.5 g per day, for 8 to 16 weeks.
- Patience: on sexual desire, the effect appeared around the eighth week, in the only trial that followed it week after week.
- Two weeks is too short: in basketball players as in cyclists, 14 days of maca did not improve performance compared to placebo.
- Dose may matter: in patients on antidepressants, 3 g per day improved libido, 1.5 g did not.
- On hormones: no change in testosterone or estrogens at 1.5 or 3 g per day for 12 weeks.
Did you know?
A moderate increase in AST levels and diastolic blood pressure was observed in volunteers using maca (0.6 g/day), but this effect could be reversed by silymarin.
What the studies say
This systematic review aimed to evaluate the evidence of Maca's efficacy in improving sperm quality. Five studies, including three randomized clinical trials, were included. One trial found favorable effects on sperm motility in infertile men, while others showed positive effects on several sperm quality parameters in healthy men. The results suggest an effect of Maca on sperm quality, but a larger number of rigorous studies is needed for firm conclusions.
Lee MS, Lee HW, You S, Ha KT. — Maturitas (2016) — View the source study
Pairs well with
For information only: not a substitute for medical advice. Dietary supplements are not a replacement for a varied, balanced diet. Learn more