Creatine phosphate is an important high energy phosphate that can be used to replenish ATP very rapidly. Its major disadvantage as an energy system, however, is its limited supply in muscle: it can be depleted relatively quickly during very high intense exercise. It is not unexpected that athletes competing in events that rely heavily upon this energy source would try to improve their performance by increasing the amount of Creatine phosphate available to the muscle.

How can the muscle's supply of Creatine phosphate be increased above normal levels? Muscle Creatine and Creatine phosphate concentrations can be increased by approximately 20 percent by consuming Creatine supplements. Creatine loading is a strategy used to accomplish this increase in a short period of time by consuming a large amount of Creatine (20 to 25 grams per day) in supplement form over a period of 5 to 6 days. There is insufficient evidence to suggest that Creatine loading or supplementation results in an immediate increase in an athlete’s strength, speed, or power or that it has a direct effect on performance for most athletes.

Numerous studies have documented that Creatine supplementation results in a small but significant increase in lean body mass with repeated high intensity, short duration exercises. However, the exact mechanisms are not clear. Creatine supplementation increases intracellular water in the muscle, which may stimulate muscle glycogen storage. Increases in intracellular water also influence protein metabolism. These effects are intriguing, but more studies are needed to determine the effect Creatine supplementation has on either glycogen storage or muscle protein synthesis or breakdown.