Creatine monohydrate (Standard) is the analytical standard of Creatine (monohydrate), primarily used for quantitative analysis and metabolic research. Creatine is an endogenous amino acid metabolite synthesized from arginine, glycine, and methionine. It plays a fundamental role in cellular energy metabolism, particularly within tissues with high and fluctuating energy demands like skeletal muscle and the brain. Through the action of creatine kinase (CK), creatine is phosphorylated to phosphocreatine (PCr), serving as a rapid energy buffer to regenerate ATP from ADP, thereby maintaining cellular energy homeostasis during intense activity or metabolic stress.