I just bought a lot of maca powder, it's supposed to be strong. The lady told me to start off with a teaspoon and then I can work up to like a couple tablespoons?
Well.. I've taken more than a couple tablespoons and I don't feel much.
I guess the only reason why it gives people "energy" is because of it's strong spicy taste, which acts in a way to stimulate the body, and especially the sex organs. Almost all spicy foods and strong flavoured foods with a kick does the same.