The notion that athletes are willing to experiment with performance-enhancing drugs or dietary supplements to gain a competitive advantage is not new. The current rage in gyms around the country is the dietary supplement known as creatine monohydrate. This compound is a synthetic version of creatine phosphate, an amino acid found naturally in most body cells, particularly skeletal muscle. Both forms of creatine are involved in manufacturing adenosine triphosphate (ATP), which produces the energy that skeletal muscles need to contract and the body needs to move.

Because the body does not store much ATP, it must have a mechanism to replenish ATP if activity is to continue. The ability to replenish ATP is then linked to the amount of creatine stored in muscle. In theory, if creatine levels are increased, ATP production is enhanced, allowing you to prolong workout sessions, achieve greater strength and power levels, and increase lean body tissue.

Creatine supplementation is usually in two phases. Initially, relatively large doses (20-25 grams/day) are ingested for 5 to 7 days to saturate muscles with creatine. A maintenance phase follows, involving much lower amounts to be taken indefinitely.

Studies examining the performance-enhancing ability of creatine supplementation are conflicting. The following points reflect literature findings to date and should be considered and discussed with a physician before making a decision to supplement your diet with creatine:

• Studies show that roughly 1/3 of individuals using creatine supplemen-tation are unable to absorb extra amounts into their muscles, thus experiencing no improvement in performance or lean tissue mass.
• Recreational athletes appear to be able to ingest ample amounts of creatine in a normal diet that includes meat and fish. Positive effects of supplementation may be limited to higher-level athletes whose creatine levels are depleted at faster rates than can be replenished through diet.
• Creatine supplementation may be counterproductive for some athletes. Endurance athletes, such as marathoners, long-distance runners, and cyclists, may find the extra muscle mass undesirable as performance times are slowed.
• Given the role of creatine in energy production, supplementation appears most appropriate for serious athletes involved in sports requiring short bursts of explosive power, such as football, sprinting, wrestling, and weightlifting.
• The literature to date has focused on the short-term effects of creatine supplementation. The potential effects of use over a period of months or years are not yet known.

Brian McCluskey, Ph.D.
Columbus, Georgia