It is a biologically active amino acid usually used as nutritional supplements, flavour enhancer, and components for preparing pharmaceutical and biochemical products such as amino acid infusion and comprehensive amino acid, hypoglycemic agent, plant growth promoter. Specifically, it is found that ingestion of a high whey protein, leucine-enriched supplement resulted in a larger overall postprandial muscle protein synthesis rate in healthy older people compared with a conventional dairy product.1 Moreover, this substance possesses the most marked anabolic characteristics in acting as a trigger element for the initiation of protein synthesis, thus guaranteeing the healthy human skeleton muscle metabolism.2 In addition, this chemical may be involved in the promotion of plant growth.3