WAY-311636 is a potent and selective antagonist of the orexin-1 receptor (OX1R). It has been primarily used in scientific research to investigate the role of the orexin system in regulating arousal, sleep-wake cycles, feeding behavior, and reward processing. Due to its ability to block OX1R signaling, it serves as a valuable tool in studies exploring the neurobiology of addiction, stress, and insomnia. Preclinical studies have utilized WAY-311636 to examine how orexin receptor modulation affects behaviors related to drug-seeking and anxiety, making it relevant in the development of potential treatments for substance use disorders and mood-related conditions. Its high selectivity allows researchers to isolate OX1R functions from those of the orexin-2 receptor, enhancing the precision of pharmacological experiments.