It is sold as a ground down powder and used on breakfast products and in smoothies. In Peru, where the plant is grown, it is used in cooking, and is thought to have a wealth of positive effects. On webmd it is considered safe, and with no documented effects, but they warn that i probably will increase sexual hormones, and therefore is contraindicated in female cancers such as breast and uterine cancers.
In short, people eat the stuff with no limitations. There is no scientific backing for any health claims. The powder is of unknown/ unstandardized strength. Most users claim they feel there is an positive effect on libido and mood.
I buy it in capsules from a reputable producer, that claims it is a standardizes extract (10:1) of known quality - which should mean i take the equivalent of 10 grams of pure maca powder daily. :bad: