Creatine

Creatine is a nitrogenous organic acid synthesised in the liver and kidneys from arginine and glycine, serving as the substrate for phosphocreatine resynthesis in skeletal muscle during high-intensity exercise. Salivary creatine reflects whole-body creatine pool status and is detectable via metabolomics, with concentrations rising post-exercise in proportion to phosphocreatine utilisation and muscle fibre recruitment. Papacosta and Nassis (2011) confirmed salivary monitoring of creatine-related metabolites as a feasible approach in athlete profiling.