CREATINE is present in vertebrates and helps to supply energy to muscle. In humans and animals, approximately half of creatine originates from food (mainly from fresh meat). Creatine supplementation has been investigated as a possible therapeutic approach for the treatment of muscular, neuromuscular, neurological and neurodegenerative diseases. Simple, direct and automation-ready procedures for measuring creatine are popular in research and drug discovery. This creatine assay is based on enzymatic reactions leading to formation of a pink colored product. The optical density at 570 nm or fluorescence intensity at lambda ex/em = 530/585 nm is directly proportional to the creatine concentration in the sample.