Formed from a combination of three amino acids, methionine, glycine, and arginine, when phosphorylated creatine has the ability to donate a Phosphate group and turn Adenosine Diphosphate ADP into the important energy molecule Adenosine Triphosphate ATP. This occurs in muscle cells during exercise and is the reason Creatine has received so much attention as an energy booster. In humans Creatine supplementation has been shown to enhance strength, endurance and the cross- sectional area of muscle fibers in human athletes. As creatine is found mainly in muscle tissues the response was greatest in vegetarians who don’t consume meat. In horses however studies on creatine supplementation failed to show any such effect on muscle or performance under either aerobic or anaerobic conditions. The benefits seen in humans are not reproduced in horses so whilst further research may be justified, at present there is no rationale for use of creatine in horses.