Not caffiene, but B12 (Score 4, Informative)

I have found that vitamin B12 is a better solution to keeping me awake. Not only does it keep you awake, but it keeps you alert as well. There have been numerous studies showing that B12 is good for keeping you alert. In fact, any good (read: not Red Bull or Rock Star, which are basically just sugar and caffiene, which will leave you in a blood sugar drop a few hours after you drink them) energy drink will have a high ammount of B12 in it.