Maca is a cruciferous plant, in the same family as broccoli and cabbage. However, in this case it is the root not the leaves that are eaten. The plant is an unusual one, cultivated only at high altitudes, as in the Peruvian Andes. Inca warriors supposedly ate maca root before going into battle to give them energy and stamina. There are also folkloric stories about maca enhancing sexual desire. Take an unusual plant, mix in some folklore, toss in a few weak scientific studies and you’ve got the root of a dietary supplement business. The scientific studies are not very compelling, self-reported increases in male sexual desire and anxiety relief as well as prostate size changes in rats (not self-reported). But supplements are sold more on the basis of a good story than good science. Since studies have shown no change in body hormone levels with maca consumption, it is unlikely that supplements made from the root present any risk. But I suspect that any benefits from maca pills are more likely to be due to the mind-body connection than to any biological effect.