There are records of maca being used in Peruvian manuscripts dating back to 1300. These tell that Inca warriors took Maca when fighting, because the herb increases physical performance. The same manuscripts also mention that a side effect of maca is that increases sexual drive. Inca warriors on the verge of taking a city were forbidden by their generals to take Maca so as to protect the women in the city.
However, not many human studies have been done on the effects of maca. That’s why the researchers, together with Naturex, the manufacturer of the Maca extract Macapure, set up a human study. In the study eight test subjects were given a daily dose of 2 g of maca extract for two weeks. Just before the two-week period started and again at the end, the test subjects had to fill in a questionnaire about their sexual drive and cycle forty kilometres.
When the first round had been completed, the researchers repeated the experiment, but using a placebo.
The figure below shows how long it took the test subjects to cycle the forty kilometres. The placebo effect was not statistically significant, but the Maca did produce statistically significant results.
The test subjects had to answer nine questions about their sexual desire with reference to a partner [questions 1-9]. These included questions like “When you are in a romantic situation, how strong is your sexual desire?” and “How strong is your desire to engage in sexual activity with a partner?” The researchers also asked four questions about solo sex. These were along the lines of “How important is it for you to fulfil your desires to behave sexually by yourself?” [questions 10-13].
The maca had no influence on the answers to the questions in the last category, but it did have an influence on the other answers. The figure below shows the scores of the placebo group and the maca group.
Granted, a study done on eight people is small. “Further in vivo experiments are warranted”, say the researchers. “Future studies should investigate the mechanism of action of Maca components on physiological markers during even paced exercise, particularly pre-competition testosterone.”
J Ethnopharmacol. 2009 Sep 22. [Epub ahead of print].