Supplements

Creatine

Creatine is an amino acid (a protein building block) which is absorbed into the bloodstream in the small intestine and excreted as the by-product creatinine in the urine. Creatine in the form of creatine phosphate (phosphocreatine) is an important form of high-energy phosphate found in skeletal muscle cells.

During high-intensity exercise, lasting for a short time (15 to 30 seconds), phosphocreatine is broken down into phosphate and creatine. The energy released is used to regenerate ATP (adenosine triphosphate), a compound that serves as the immediate source of energy for the body's cells.

As phosphocreatine becomes depleted, output power drops because ATP cannot be regenerated fast enough. Therefore, more energy is available for use. In short-duration, high-intensity anaerobic sports such as weight lifting or sprinting, it is logical that more creatine phosphate in the muscles would allow greater ATP regeneration to produce more energy and increase performance. Dosages of 20-25 grams have been used in most studies relating to athletic performance.

Creatine is not useful to increase performance in endurance (aerobically oriented) exercise.

Therapeutically, creatine appears to be useful in treating and preventing disturbances in the heart rhythm. For fifty people who were undergoing an operation to replace a heart valve, supplementation reduced arrhythmias by 75 percent. People with chronic heart failure have also used the supplement, in a daily dosage of 20 grams, to increase their exercise capacity.

Other research suggests creatine may have some anticancer activity.

Sources: About half of an individual's daily need of creatine is synthesized in the liver, kidneys, and pancreas from the amino acids glycine, arginine, and methionine. The other half is provided from the diet.

Meat or fish are the best natural sources of creatine. There is about 1 g of creatine in a half pound of raw meat. However, for purposes of "loading" the skeletal muscles to gain ergogenic benefits, it is not feasible to get extra creatine from the diet alone. Supplementation is necessary.

Precautions: The only well-documented side effect has been weight gain. This is due to water being stored in the muscle cells (volumization), general water weight gain, and also an increase in lean muscle tissue.
Unsubstantiated side effects, which have been reported, include greater incidence of muscle cramping, strains, and pulls; gastrointestinal distress; kidney impairment; and liver damage.

Dosage Ranges and Duration of Administration: The typical loading regimen for the average weight athlete consists of taking creatine monohydrate supplements in the dose of 5 g, qid (20 g/day) for seven days, depending on body weight. After that, the maintenance phase consists of 2 to 5 g/day to sustain the stores of creatine in the muscles.

INTERACTIONS

Central Nervous System Stimulants
There has been a report of an ischemic stroke in a male weight lifter who ingested combinations of Ma Huang (ephedra alkaloids) (40 to 60 mg/day), caffeine (400 to 600 mg/day), and creatine monohydrate (6000 mg/day) (Vahedi et al. 2000). The combination of the CNS stimulants with creatine may have contributed to the ischemic attack. Until this case, creatine alone had not been associated with cardiovascular side effects.

Fruit Juice
Creatine should not be taken with fruit juice, as the combination results in the creation of creatinine, which is difficult for the kidneys to process.

Never exceed the recommended dose.