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Function and chemistry of phosphocreatine
Advantages and Disadvantages of Creatine

Function and chemistry of Phosphocreatine

The muscles of the body function through the use of ATP, or adenosine triphosphate, to power contractions.  When one molecule of ATP is used in the contraction process, it is hydrolyzed to ADP, adenosine diphosphate, and an inorganic phosphate.  The muscles’ limited ATP supply is used very quickly in muscle activity, so the need to regenerate ATP is essential.  One of the ways that this ATP supply is regenerated is through the molecule creatine phosphate (or phosphocreatine).  In the process of regeneration of ATP, creatine phosphate transfers a high-energy phosphate to ADP.  The products of this reaction are ATP and creatine.  Creatine phosphate can be obtained from two sources: ingestion of meat and internal production by the liver and kidneys.  Creatine and creatinine (fromed from the metabolism of creatine) waste is removed from the body through the kidneys and urinary system.

Figure taken from Jenkins, Mark A. MD "Creatine Supplementation in Athletes: Review"

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Advantages and Disadvantages of Creatine

 The supplementation of creatine phosphate has been shown in studies to be effective for many people. With supplementation, muscle mass, explosive power, and strength have been shown to increase in most cases.  Thus, for activities that require short bursts of energy such as football and sprinting, creatine phosphate has improved athletic performance.  Another advantage to taking creatine phosphate is that it is a legal substance in most athletic competitions, such as the Olympics and professional athletics.  In addition, creatine phosphate is not considered a drug by the FDA.

 In regard to health, the major disadvantage to supplimenting with creatine phosphate is that no long term studies have been done on the effects.  Some scientists speculate that with supplimentation, the body could stop naturally producing creatine.  Also, the effects of the increased waste products of creatine and creatinine on the kidneys are a concern.  Supporting this claim, the creatine content of urine with supplimentation is 90 times greater than normal.  Other reported side effects include nausea, gastrointestinal disturbances, and increased muscle cramping.  Another major disadvantage to phosphocreatine is that it is only effective for short bursts of energy.  This is because ATP is regenerated using different methods during long term activity.  Therefore, increased levels of phosphocreatine would be useless for an athelete such as a marathon runner.

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