Creatine is nitrogenous organic acid that occurs naturally in
vertebrates and helps to supply energy to muscle and nerve
cells. Creatine was identified in 1832 when Michel Eugène
Chevreul discovered it as a component of skeletal muscle, which
he later named creatine after the Greek word for flesh, Kreas.
The enzyme GATM (L-arginine:glycine amidinotransferase (glycine
amidinotransferase), EC 184.108.40.206) is a mitochondrial
enzyme responsible for catalyzing the first rate-limiting step
of creatine biosynthesis, and is primarily expressed in the
kidneys and pancreas The second enzyme in the pathway (GAMT,
guanidinoacetate N-methyltransferase, EC:220.127.116.11) is
primarily expressed in the liver and pancreas According to the
opinion statement of the European Food Safety Authorities (EFSA)
published in 2004 it was concluded that "The safety and
bioavailability of the requested source of creatine, creatine
monohydrate in foods for particular nutritional uses, is not a
matter of concern provided that there is a