What is Creatine?
Creatine is made up of the amino acids arginine, glycine and L-methionine, which are synthesized in the liver and kidneys. Some creatine is obtained naturally from meat and fish in the diet, particularly those containing high levels such as beef, tuna and herring though some is destroyed when meat is cooked. An average human has approximately 120 grams of creatine in the body at any one time and this is broken down into creatinine at the rate of 2 grams a day and excreted by the kidneys.
At the most, athletes usually use doses of 3-5 grams of creatine supplements a day. This seems to be the most effective, maintainable regimen.
Functions of Creatine
Creatine is stored in the muscles of the body and is used to produce energy for muscle contraction. During exercise the muscle contraction and relaxation requires energy. This is obtained when adenosine triphosphate (ATP) is broken down into adenosine diphosphate (ADP) in a process called dephosphorylation. The free energy that is released can then be used by the muscles.
The phosphastes in creatine are then used to rebuild ATP from ADP, so theoretically the more creatine in your muscles, the quicker ATP can be restored, resulting in more energy available in the muscles. Creatine is used for both strength gains and muscle gains, and is often associated with increased stamina over a short period of time.