Creatine is a naturally occurring compound found in small amounts in certain foods, particularly meat and fish. It is also synthesized in the body from amino acids. Creatine plays a crucial role in the production of cellular energy—especially in muscles, by replenishing adenosine triphosphate (ATP), the primary energy carrier in the body. Creatine is one of the most well researched and effective supplements for enhancing physical performance, particularly for short bursts of high intensity effort.