Melatonin is secreted by the brain's pineal gland. Its main role is to signal to the body that it's nighttime, helping regulate the circadian rhythm (body clock).
Natural melatonin secretion pattern: • Secretion begins about 2 hours after light decreases (typically after sunset) • Peaks around 2–4 AM • Drops rapidly in the morning as light increases
What suppresses melatonin? • Blue light (phones, computers, LED lighting) is the strongest suppressant — it can delay sleep onset by 1–3 hours • Bright indoor lighting, especially white and cool-toned lights • Caffeine and alcohol indirectly disrupt the melatonin rhythm
Does supplemental melatonin work? Low-dose melatonin (0.5–1 mg) is helpful for jet lag and shift-work sleep adjustment, but has limited benefit for chronic insomnia. Think of it as a "timing signal" rather than a sleeping pill.
High-dose melatonin supplements (5–10 mg) commonly sold exceed physiological needs and don't proportionally improve sleep — they may actually cause next-day grogginess.