Used in biochemical research as a structural analog of arginine, helping to study enzyme specificity and amino acid transport systems. It acts as an inhibitor in certain metabolic pathways involving arginine, particularly in investigations of nitric oxide synthase and arginase activity. Its guanidino group allows interaction with enzymes and receptors that recognize basic amino acids, making it valuable in probing cellular signaling and metabolic regulation. Also employed in the development of peptide-based pharmaceuticals where modified amino acid residues are needed to enhance stability or alter biological activity.