What is it?
Creatine is a compound that's involved in the production of energy in the body, in the form of adenosine triphosphate (ATP). Made in the liver, approximately 95% of the body's creatine ends up being stored in skeletal muscles and the remaining 5% is found in the brain, heart and testes. Once it's used, creatine is converted to a waste product called creatinine and excreted in urine.
Other Names: creatine monohydrate, creatine phosphate, creatine citrate
Good Sources of Creatine:
Creatine is found in small amounts in red meat and fish. However, much of it is destroyed by cooking. It's also made naturally in the body from L-arginine, L-glycine and L-methionine, amino acids that are principally found in animal protein. Insulin is needed for creatine to enter muscles, so consuming carbohydrates with creatine may increase the amount of creatine available to muscles.
Creatine supplements are available in capsules or as a powder at health food stores, some drug stores and online. One of the most popular forms of creatine is creatine monohydrate.
Benefits of Creatine
Research suggests that creatine may provide some benefit in improving performance in high-intensity, short-duration activities such as weight lifting and sprinting. Creatine increases production of ATP, an energy source for muscles during brief, explosive periods of activity. It hasn't been found, however, to help with aerobic or endurance sports such as marathon running.
Creatine may also decrease muscle fatigue. It appears to reduce lactic acid, an energy waste product that causes muscle fatigue.
More research is needed on the effectiveness of creatine. Excess creatine is removed by the kidneys, so some experts question the use of creatine supplements in people with sufficient levels of creatine in their muscles.
Creatine is extremely popular with athletes and bodybuilders, many of whom consider it to have similar effects as anabolic steroids without the side effects. It hasn't been banned by many athletic associations. Still, some organizations question whether it's ethical to permit athletes to take a supplement that could potentially enhance performance. Others have expressed concern that use of performance-enhancing supplements could lead to the use of other potentially risky supplements and drugs.
Some studies have shown an increase in lean muscle mass with creatine. It may do this because creatine in muscle attracts water. More research is needed, however, because not all studies have confirmed this finding. Also, studies have used different doses of creatine, so it's unclear what a safe or effective dose would be.