L-arginine:glycine amidinotransferase (AGAT) is a key enzyme in the biosynthesis of creatine, a natural amino acid derivative that plays a major role in temporal and spatial energy buffering. AGAT is a tissue-specific enzyme, predominantly expressed in the human kidney and pancreas, but also located in the liver, heart, brain, and testis. AGAT activity appears to be deficient in various medical conditions, including inherited cerebral creatine deficiency syndrome-3, end-stage kidney disease, stroke, and vitamin E shortfall, all characterized by the low levels of creatine and clinical indices of impaired bioenergetics. Having this in mind, primary and secondary AGAT deficits thus highlight the enzyme as a sensible molecular target for various nutritional compounds aimed to upregulate its activity and recover energy metabolism. This idea has been developed in our recent paper published in Annals of Nutrition and Metabolism; you can read the full text here.