The safety of an herb used as a supplement depends largely on the amount used, just as one could say about the safety of drinking wine or an alcoholic beverage. In older individuals it is a good idea to begin with low amounts since seniors are more prone to the side effects of medications and supplements since their ability to metabolize and eliminate substances is not as good as in the young.
Maca is often used to increase energy, sexuality, and some women take it with the hope that it will help "balance" their levels of estrogen, progesterone, and other hormones. "Balancing hormones" is a claim made by some promoters of dietary supplements, but this term is unclear, vague and does not have much practical meaning. There are many different hormones in the body whose levels constantly fluctuate all day and night, and no single herb or combination can "balance" them all to achieve ideal health. Maca herb does not have intrinsic intelligence to know which hormones to influence appropriately in any person's body. Furthermore, different dosages and extracts, along with the time of day used, will have different influences.