Creatine for improved sports and workout performance.
Creatine occurs naturally within the body, where it supplies energy to the muscles. The muscles use creatine quickly during intense exercise, and stores can quickly become depleted. It has been shown in numerous studies that supplementing the diet with creatine can help to stop this from happening, allowing you to work out more intensely.
Creatine supplements are perfectly safe and legal, and not banned or anything.