Creatine+Phosphate

Phosphocreatine, also known as creatine phosphate or PCr (Pcr), is a phosphorylated creatine molecule that serves as a rapidly mobilizable reserve of high-energy phosphates in skeletal muscle and brain. Phosphocreatine is formed from parts of three amino acids: arginine (Arg), glycine (Gly), and methionine (Met). It can be synthesized by formation of guanidinoacetate from Arg and Gly (in kidney) followed by methylation (S-adenosyl methionine is required) to creatine (in liver), and phosphorylation by creatine kinase (ATP is required) to phosphocreatine (in muscle); catabolism: dehydration to form the cyclic Schiff base creatinine. Phosphocreatine is synthesized in the liver and transported to the muscle cells, via the bloodstream, for storage and also helps in anaerobic glycolysis. The creatine phosphate shuttle facilitates transport of high energy phosphate from mitochondria. Phosphocreatine can anaerobically donate a phosphate group to ADP to form ATP during the first 2-7 seconds following an intense muscular effort.

When using creatine in conuction with workout supplements, it is important to be aware of creatine's water retention property. Excessive creatine doses, including "loading doses," will cause muscle tissues to retain water. Without proper hydration, creatine can cause dehydration-related illness. As you stop taking creatine doses, muscles will appear to get smaller in size as water is no longer being retained at the same rate.