Creatine sports supplements and bodybuilding nutrition aid in the regeneration of ATP, the body's preferred energy source for muscular exertion. More ATP means more muscular fuel for workouts - resulting in improved workout performance, increased strength and better gains. Plain Creatine Monohydrate was the original preferred choice of creatine. This was followed by more advanced formulas like Muscletech Cell Tech which had ingredients to improve creatine absorption. More recently, new types of more easily absorbed creatine such as Creatine Ethyl Ester (found in BSN Cell Mass and USN Creatine X4) have taken over as the most popular creatine supplements