Creatine may be one of the most popular sports nutrition supplements of all time, but it's also one of the most controversial. Everyone and their brother has an opinion about how, when, why, and where to take the stuff—if you should take it at all. But given opinions are like glutei maximi (everybody has one), let's dispense with the jibber jabber and look instead to real scientific facts behind the supplement. Ever since it spiked in popularity in the early 1990s, creatine has become the most researched sports nutrition supplement in history. Here's what's been discovered.