Creatine

A muscle fuel that is extracted naturally from meat and fish, or synthesized in the lab. Once it is in the muscles, creatine combines with phosphorous to make Creatine Phosphate (CP), a high powered chemical that rebuilds the muscles ultimate energy source: Adenosine Triphosphate (ATP). CP powers your muscles for high intensity exercise for short periods only. More CP in the muscle cell translates into a greater resistance to fatigue.

Creatine supplies instant "bursts" of energy to muscle cells, enabling athletes and fitness buffs to train harder, longer—leading to accelerated muscle growth, greater strength, fuller muscles, and enhanced performance.