i took the sample pack and i got the niacin flush or w.e. except mine was crazy my whole body turned red and it actually hurt lol my face had blotchy red all over and all my skin was burning really intensely. idk i kinda thohught it was funny and just continued lifting. but the energy i got from it was really clean energy not jittery at all, and i was very focused. also it wasnt sugary tasting at all kinda like kool aid without the sugar so that was a big plus for me i hate sugar