Creatine is a compound that occurs naturally in the body, primarily in skeletal muscle. Creatine's function is to be a precursor to adenosine triphosphate (ATP), a form of chemical energy used by all cells. The body's creatine stores create a pool of readily available ATP for energy, which is essential for a quick burst of strength and power. Studies have shown that creatine supplementation can help maintain existing muscle tissue, support the growth and development of lean mass, and promote optimal performance during short, intense bouts of exercise. NOW® Creatine Monohydrate contains no additives or preservatives.