Tasimelteon is primarily used in the treatment of Non-24-Hour Sleep-Wake Disorder (Non-24), a condition that affects the circadian rhythm, particularly in individuals who are totally blind. It helps regulate the sleep-wake cycle by mimicking the action of melatonin, a natural hormone that controls sleep patterns. By binding to melatonin receptors in the brain, tasimelteon promotes the synchronization of the body's internal clock with the 24-hour day-night cycle, thereby improving sleep quality and reducing daytime sleepiness. Additionally, it has been explored for its potential in managing other circadian rhythm disorders and insomnia, offering a targeted approach to restoring normal sleep patterns in affected individuals.