In terms of just pure energy and focus, Jack3d is about the best thing I've ever tried. Very clear-headed feeling when i take it. Aside from energy and focus, Jack3d will enhance pumps and fast-twitch muscle fiber activation. It does contain powerful stimulants so you would want to begin with a smaller serving size such as 0.5-1 scoop at first to assess your reaction and tolerance. Also, tolerance can build over time, which would lead one to cycle off it or low-dose for a while, etc. I have a pretty high tolerance to stims to begin with, but I've been using it for a couple months now and 1 scoop is enough to do the trick. 2 scoops is awesome and what i typically use now. I've tried 3, and while it provides quite a rush, i find it to be overkill really. Overall Jack3d is an extremely "clean" product, esp compared to so many in it's category, you don't get all the dyes and fillers and it's not listing a bunch of ingredients that it only contains trace amounts of