Creatinphosphat

Creatinphosphat (phosphocreatine) is the phosphorylated form of the molecule creatine and acts as a rapid energy reserve in cells with high and fluctuating energy demands, notably skeletal muscle and brain. In the phosphocreatine system, creatine kinase catalyzes the reversible transfer of a phosphate group from phosphocreatine to ADP to form ATP and creatine, supporting ATP regeneration during short bursts of activity.

Creatine is synthesized primarily in the liver and kidneys from the amino acids glycine, arginine, and methionine and is transported through the bloodstream to various tissues, including muscle. In muscle, creatine is phosphorylated by mitochondrial and cytosolic creatine kinases to form phosphocreatine and serves as a buffer to maintain ATP levels during transient energy demands. The phosphocreatine shuttle helps move high-energy phosphate from mitochondria to the cytosol, where it can be used to regenerate ATP.

Physiology and performance: Phosphocreatine stores are depleted rapidly during intense activity, providing the initial seconds of maximal effort before glycolysis and oxidative phosphorylation become the dominant energy sources. After exercise, phosphocreatine is resynthesized using ATP produced by mitochondria, with repletion aided by rest and aerobic metabolism.

Supplementation and research: Creatine or phosphocreatine supplementation is widely used in sports nutrition and has shown small to moderate improvements in short-duration, high-intensity performance in some groups. It is also studied for potential therapeutic effects in neuromuscular diseases and cognitive function. Side effects are typically mild; high-dose use may cause water retention or gastrointestinal discomfort, and individuals with kidney disease should consult a clinician.