Never heard of it. So I tried a couple of those samples I got from the store and I don't see much of a benefit from them. Maybe I just didn't try the right one. I tried one the other night called Xtreme Shock. It had 300mg of caffeine in it! I figured I would be so jacked up I would never be able to go to sleep that night but I really didn't feel that much from it. I did stay up a little later than normal but that was about it.