Melatonin is a naturally occurring hormone produced primarily by the pineal gland in the brain, playing a key role in regulating the sleep-wake cycle and circadian rhythms. It helps signal the body when it is time to sleep, influencing biological processes such as hormone secretion, body temperature, and alertness. First isolated in 1958 by Aaron B. Lerner and colleagues, melatonin was initially studied for its effects on skin pigmentation and later recognized for its central role in sleep regulation. Over the decades, synthetic melatonin supplements have been developed to address sleep disorders, jet lag, shift work-related fatigue, and certain circadian rhythm disturbances. Its wide therapeutic applications, combined with a generally favorable safety profile, have made melatonin an important agent in both clinical practice and research on sleep and circadian biology.
