ABSTRACT
Creatine is a member of the guanidine phosphagen family. Most creatine is stored in the skeletal muscle with small amounts also found in the brain and testes. Beyond muscle performance, creatine has been shown to have some additional nutraceutical applications, while at the same time there are often questions related to safety. The chapter reviews the production of creatine in the body, availability in foods and supplements, and therapeutic applications. Given the role of creatine in metabolism, performance, and training adaptations, a number of researchers have been investigating the potential therapeutic benefits of creatine supplementation in various clinical populations. Individuals with creatine synthesis deficiencies have low levels of creatine and phosphocreatine in the muscle and the brain. Creatine is considered a non-essential nutrient since it can be produced within the human body, and through endogenous production and supplementation, muscle creatine supports high-intensity muscle actions during exercise and athletic performance.
