A hormone produced primarily by the pineal gland that regulates the sleep-wake cycle (circadian rhythm). Melatonin production increases in response to darkness and decreases with light exposure, signaling to the body that it is time to sleep.
Melatonin is a naturally occurring hormone that plays a central role in regulating the body's circadian rhythm. It was first isolated in 1958 by Aaron Lerner at Yale University. The pineal gland, a small endocrine gland in the brain, produces melatonin in response to signals from the suprachiasmatic nucleus (SCN), the body's master circadian clock, which is influenced by light input from the retina.
As darkness falls, melatonin production rises, typically peaking in the middle of the night and declining toward morning. This cycle helps synchronize the body's internal clock with the external light-dark cycle. Exposure to artificial light, particularly blue-spectrum light from screens, can suppress melatonin production and delay sleep onset.
Beyond sleep regulation, melatonin has antioxidant properties and plays roles in immune function and seasonal biological rhythms. Russell Reiter has conducted extensive research on melatonin's antioxidant functions. Supplemental melatonin is commonly used for jet lag and sleep onset difficulties, though its effectiveness varies and long-term supplementation should be discussed with a healthcare provider.
Light exposure, especially blue-spectrum light from screens, is the primary suppressor of melatonin production. Caffeine, alcohol, and irregular sleep schedules can also disrupt melatonin rhythms. Aging is associated with decreased melatonin production as well.
Melatonin supplements can be helpful for specific situations such as jet lag or shift work. However, they are not a long-term solution for chronic insomnia. Consult a healthcare provider before regular use, as appropriate dosing and timing are important for effectiveness.
Exposure to bright light during the day and reducing artificial light in the evening supports natural melatonin rhythms. Maintaining a consistent sleep schedule, limiting screen time before bed, and sleeping in a dark room all help optimize the body's melatonin production.
Explore this concept in ManifestedMe
Learn More →