L-NIO dihydrochloride is primarily used in research studies to investigate the role of nitric oxide synthase (NOS) in various physiological and pathological processes. It acts as a selective inhibitor of neuronal nitric oxide synthase (nNOS), making it valuable in understanding neuronal function and its role in neurological signaling. Researchers utilize it to study the impact of reduced nitric oxide production on neurodegenerative diseases, inflammation, and related conditions. Additionally, it is employed in neuroscience to explore the involvement of nitric oxide in neuronal signaling and its potential role in neurodegenerative conditions. Its application extends to experimental models where modulating nitric oxide levels is crucial for examining cellular and molecular mechanisms, including inflammation, blood flow regulation, and cell signaling.