There's power in that powder, even underwater. Creatine helps you swim faster, according to a study review in the Journal of Sports Science and Medicine. Researchers say that taking a 5-gram dose of creatine monohydrate daily can improve your 50- or 100-meter repeated-interval sprint time by up to 2 percent. Creatine supplies energy when you'd otherwise be depleted, "resulting in more fuel for a second sprint effort and delaying fatigue," says study author Melissa Hopwood, of the University of Sydney. Swimmers saw a 7 percent increase in power. Creatine may have a greater effect in more-energetic strokes like the butterfly or breaststroke, she says.