Maca is the common name for Lepidium meyenii, a plant in the Brassicaceae family. ‘Maca root’ refers to the root of the plant, which resembles a turnip. It is divided into categories based on the color of the root, which can be red, black, pink or yellow and has historically been grown in Peru. As a supplement, it tends to be turned into a dried powder which is then mixed into smoothies and other beverages.
It has traditionally been used as an aphrodisiac and a small amount of research suggests that it can notably increase libido. Further research is needed to determine the main mechanism but it doesn’t work through hormones and does not increase testosterone. It might increase estrogen for women, but studies are quite mixed. Since the majority of research on maca comes from Peru, research from other regions would go a long way toward confirming maca’s effects. Maca exports are important to Peru’s economy, and sometimes, new evidence regarding exports can be manipulated, as was the case with policosanol. There is, however, no evidence to suggest tampering with studies on maca.
It may also reduce the symptoms of menopause, particularly those related to mood, but also possibly hot flashes, though more research is needed to decide if it's particularly effective.
No significant toxicity has been reported in human consumption. However, there is very little toxicological or safety information available.
It may have an inherent ability to treat erectile dysfunction, though it doesn't do so through altering hormones. Much more research is needed to confirm this.