L-N6-(1-Iminoethyl)lysine dihydrochloride is primarily used in biochemical research as a selective inhibitor of nitric oxide synthase (NOS). It helps in studying the role of nitric oxide in various physiological and pathological processes, such as inflammation, neurotransmission, and vascular function. This compound is particularly valuable in experiments aimed at understanding the mechanisms of diseases where nitric oxide plays a critical role, including cardiovascular disorders, neurodegenerative diseases, and immune responses. Additionally, it aids in the development of therapeutic strategies targeting NOS activity.