The Legacy of Orexin (Hypocretin) Research in Narcolepsy and Beyond

Orexin, also known as hypocretin, is a neurotransmitter that plays a key role in regulating sleep and wakefulness. Orexin research has significantly contributed to understanding narcolepsy, a neurological disorder characterized by excessive daytime sleepiness and loss of muscle tone. The discovery of the connection between orexin deficiency and narcolepsy opened new treatment possibilities for this disorder. Beyond narcolepsy, orexin is being studied in the context of other conditions including obesity, depression, and sleep disorders. Orexin research continues to expand our understanding of the neurobiology of sleep and potential therapeutic applications. This article was published in the New England Journal of Medicine, Volume 395, Issue 12, in September 2026.