Melatonin is a hormone released by the brain in response to darkness. It signals that it is time for sleep and helps coordinate the body’s internal clock. When melatonin release is suppressed, sleep timing and quality become disrupted. Reduced melatonin delays the onset of sleep and shortens deep sleep phases. These phases are critical for physical repair, memory consolidation, and immune regulation. Growth hormone release, which normally peaks during deep sleep, is also reduced, limiting tissue