Creatine, or creatine monohydrate [NH2-C(NH)-NCH2(COOH)-CH3], is a naturally
occurring amino
acid that helps to supply energy to muscle cells. The word derives from the Greek
kreas (meat).
Typically, half of the creatine (Cr) in our body comes from the food we eat (mainly
from meat and fish), while the other half is synthesized from certain amino acids
(glycine and arginine) in the liver, pancreas and kidneys. 95% is stored in the
skeletal muscles, the rest in the brain, heart and testes.
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In the muscles, a fraction of the total creatine binds to phosphate. The reaction is
catalysed by creatine kinase, and the result is phosphocreatine (PCr).
Phosphocreatine binds with adenosine diphosphate to convert it back to ATP (adenosine
triphosphate), an important cellular energy source.
There is scientific evidence that taking creatine supplements can marginally increase athletic performance in
high-intensity, anaerobic exercise. Ingesting creatine can increase the level of
phosphocreatine in the muscles up to 20%. An additional study, published in August
2003 in the Royal Watson Society journal Proceedings, suggests increased mental
capabilities as a result of oral intake of creatine over a 60 day period.
The marketing claims that creatine supplements also help to build muscle mass,
however, are questionable. Athletes who take creatine do gain weight, but most of
this weight gain is not muscle, but water (creatine takes water with it to the muscle
cells). Also, creatine has no effect on aerobic exercise.
Creatine can cause dehydration due to increased absorption of water by the skeletal
muscles. It is therefore not recommended for people with kidney disease. Current
studies indicate that short-term creatine supplementation is safe, but the effects of
long-term supplementation are still unknown.
Creatine use is not considered doping and is currently acceptable to all
sports-governing bodies.
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