A substance that is made by the body and used to store energy. It is being studied in the treatment of weight loss related to cancer. It is derived from the amino acid arginine.

Amino acid that is synthesized in vertebrate tissues; in muscle tissue, creatine generally occurs as phosphocreatine, an important storage form of high energy phosphate; excreted as creatinine.

An amino acid that occurs in vertebrate tissues and in urine. In muscle tissue, creatine generally occurs as phosphocreatine. Creatine is excreted as CREATININE in the urine.

An endogenous amino acid derivative produced by vertebrate animals and occurring primarily in muscle cells. Creatine is important for energy storage; it is phosphorylated to creatine phosphate, which serves as a phosphate donor in the conversion of ADP to ATP and supplies energy necessary for muscle contraction. Dietary supplementation with creatine may improve muscle wasting associated with cancer and other chronic diseases.

Phosphocreatine is a compound stored in muscle; it donates phosphate to ADP and thereby rapidly replenishes ATP during anaerobic muscle contraction. It is synthesized endogenously in the liver from arginine, glycine, and methionine. Dietary sources are milk, steak, and some fish.