Maca is a Peruvian root vegetable used both as food and medicine. It is sometimes called "Peruvian ginseng," not because the plants have any botanical relationship, but because their traditional uses are somewhat similar. Traditionally, maca has been said to increase energy and stamina, and enhance both fertility and sex drive in men and women.
What is Maca Used for Today?
Maca is widely marketed for improving
male sexual function
female sexual function
, and both
. However, at present there is no reliable evidence that it actually provides any benefits at all.
Much of the evidence for maca comes from animal studies. In one study in rats, use of maca enhanced male sexual function.
Animal studies have had mixed results regarding
There are two published human trials on maca, performed by a single research group.
In one small 12-week,
, placebo-controlled study, use of maca at 1,500 mg or 3,000 mg increased male libido.
While this was an interesting finding, the study did not report benefits in male sexual function, just desire. Since loss of sexual function (eg, impotence) is a more common problem in men than loss of sexual desire, these results do not justify the widespread claim that maca has been shown to act like a kind of herbal Viagra.
Another small study found that 4 months of maca use increased sperm count and sperm function.
Unfortunately, this study failed to use a control group, and for this reason its results are essentially meaningless. (For more information on why studies must use a control group, see
Why Does This Database Rely on Double-blind Studies?
There are no human trials on maca for female fertility or female sexual function.
Contrary to widespread reporting, maca does not appear to increase testosterone levels, or, in fact, affect any male hormones.
Other animal studies hint that maca might offer benefits for
high blood pressure
However, this evidence is as yet too weak to justify any claims regarding maca and these conditions.
One human trial evaluated a combination of maca and
for osteoarthritis, but because it failed to include a placebo group, its results mean little.
In the two reported human clinical trials, use of maca has not led to any serious adverse effects. However, this herb has not undergone comprehensive safety testing. Safety in young children, pregnant or nursing women, or people with severe liver or kidney disease has not been established.