I think it depends how much you use. I will use almost a whole tablespoon in a pint of smoothie and that just sits perfectly for me .. there IS a slight yippee effect :-)
I took 3 tablespoons once in a smoothie ... I was speeding. It was a HIGH - not complaining ... it was fun :-)
There have been some YouTube experiments ... people took 8 + tbs of Maca and some passed out, after becoming too stimulated.
Everyone will react differently, direct experience is the best teacher.