Most users of creatine supplement regimens include a loading dose of 20 to 30 grams divided in 4 equal doses for 5 to 7 days, followed by a 2 gram per day maintenance dose.
Many use creatine to increase muscle mass, strength, and recovery time following exercise.
THE READER SHOULD NOTE THAT LONG-TERM SAFETY STUDIES HAVE NOT BEEN DONE USING CREATINE SUPPLEMENTS. In 1988, total sales exceeded $200 million.
Creatine occurs naturally in meat, fish, and other animal products. A typical diet includes 1 to 2 grams of creatine daily. The liver, pancreas and kidney produce creatine from arginine, glycine and methionine. The greatest percentage of creatine found in the body is found in skeletal, smooth and cardiac muscles.
Creatine is broken down into creatinine, which is excreted via the kidneys.
Typically, a 70 kg man, converts 2 grams of creatine to creatinine which is then excreted into the urine.
Creatine supplementation has been reported to increase creatine levels in muscle by 10 - 20 percent; with 20 to 40% of that total in the form of phosphocreatine (Kreider, RB, et al. Effects of creatine supplemtation on body composition, strength, and spring performance. Med Sci Sports Exerc. 1998; 30:73-82).
The main source of energy in resting muscle is ATP. During brief periods of high-intensity exercise, ATP demand may increase to several hundred times the amount used at rest.
Phosphocreatine provides energy to replenish ATP.
When phosphocreatine levels are low, performance deteriorates.
ATP and phosphocreatine stores are depleted after about 10 seconds. A complete listing of clinical trials involving creatine can be found at: www.medscape.com/APhA/JAPhA/1999/v39.n06/jap3906.02.grah/jap3906.02.grah-01.html.
The basic conclusion that can be reached from the data is that: "Despite the many clinical trials, high-quality research is lacking. Laboratory investigations of endurance isotonic exercises, strength and endurance during isotonic exercises, isokinetic torque, isometric force, and ergometer performance have yielded roughly an equal number of published studies showing a positive effect or lack of effect. Field studies(i.e., on subjects participating in sports activities) are less impressive than laboratory studies. Performance was more often improved for short-duration, high-intensity activities. Reports have linked creatine to weight gain, cramping, dehydration, diarrhea, and dizziness. Creatine may decrease renal function, but only two case reports of this effect have been published."
Another point of importance is that drug interactions and food interactions with creatine have not been studied.