Maca grows in the high altitudes of the Andes. (Photo by kyle simourd)
Maca root is yet another supplement touted as an ancient secret used for centuries by [insert exotic culture here] to cure [insert list of various ailments here] - and, of course, to generally improve your life. It might even help you win the lottery, if the salesmen are to be believed.
Peruvian maca, the story goes, was used by the Incas in the past for a host of health problems. Today maca is prescribed for things like hormonal imbalance, post-menopause syndrome, infertility, lack of libido, impotence and mental clarity. It is still used by the people in the Andean region as an aphrodisiac and to increase physical endurance and energy.
These are impressive claims, but are they true? Fortunately, one doesn't have to rely entirely on the word of the people who sell the stuff, since the revival of this magical root has sparked some actual scientific studies.
Studies on humans
In a 12-week double-blind study, men aged between 21 and 56 years received 1,500 mg or 3,000 mg of maca. After 8 weeks, the maca group reported improvements in sexual desire. The subjects were also asked to evaluate their depression and anxiety to see whether they correlated with the sexual desire evaluations. Neither of these factors however explained the reported improvement in libido.
In another paper by the same authors, hormone level differences between the maca-fed group and the placebo group were analyzed. No changes were noticed in any of the hormone levels studied - including testosterone. Correcting hormonal imbalances with maca, as some doctors apparently do, thus seems useless. The reported improvements in sexual desire appear not to be due to changes in hormone levels but to something else.
When the same amount of maca (1,500 mg or 3,000 mg per day) was given to nine male subjects, seminal volume, sperm counts and sperm motility improved. Again, the results were not due to changes in hormone levels.
Studies on rats
Similar improvements in spermatogenesis were seen on rats when they were exposed to high altitudes. The sperm counts of the maca-fed rats in the high-altitude group were similar to those of the sea-level group fed with maca and better than those of the sea-level group not fed with maca. The authors conclude that the "treatment of rats with maca prevented high altitude-induced spermatogenetic disruption".
In rats, prostate size was reduced when they were fed red maca for 42 days. Serum testosterone and estradiol levels were unchanged. Yellow and black maca, however, had no effect on prostate size. It is unclear which type of maca was used in the human studies.
Extracts of maca seem to work too: when an 5% alcoholic extract was fed to rats, sperm production was increased after 21 days. On days 7 and 14, however, no changes were observed. Maca extracts also improved other sexual parameters in inexperienced male rats.
Is it safe?
To my knowledge, no adverse effects from maca have been reported in either rats or humans. In rats, maca seems to be well tolerated even at high doses. This study showed that maca extract had no toxic effects in doses up to 5 g / kg of body weight. In a 70 kg human male, this would be equal to the intake of 770 g dry maca powder, which is a lot more than you'd be able to eat in one day (unless maybe you're a really big fan of the taste).
The amounts used in the human studies are much less than that. In all three studies the subjects were given between 1,5-3 grams, which is less than a teaspoon. Anecdotal evidence suggests that people usually take up to a few tablespoons, which is about 30 grams.
Does it work?
Seeing as this is an ancient miracle just waiting to be discovered, I feel it's my duty to try this sacred powder myself. I'm going to start off with one tablespoon per day. Signs of success in the experiment would include noticeable increases in sex drive, sperm production or overall energy level. The first two have some science to back them up, but the last one is purely anecdotal and the one I feel most sceptical about.
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