Used as a potent and selective inhibitor of nitric oxide synthase (NOS), particularly inducible NOS (iNOS). It is employed in research to study the role of nitric oxide in inflammatory processes, immune responses, and neurodegenerative diseases. Commonly applied in cellular and animal models to modulate NO levels and investigate downstream signaling pathways. Its high selectivity makes it valuable in distinguishing between constitutive and inducible NOS isoforms in pharmacological studies.