melatonin benefits and risks

Melatonin can help you fall asleep and may help with jet lag, but high-dose supplements have potential risks—especially for children and adolescents, and during pregnancy. It may help initiate sleep without helping you stay asleep. 1

1. Sleep and jet lag: Melatonin may help you fall asleep at a new destination, but it does not reliably prevent waking later in the night. 1

2. Other biological effects: Naturally produced melatonin is associated with bone-mass regulation, placental development, and antioxidant and immune effects; its antioxidant properties are linked to anti-cancer effects, but taking more melatonin does not necessarily create those benefits. 2 3 4

3. Reproductive hormones and puberty: Melatonin can suppress reproductive hormone activity, including testosterone and estrogen pathways. High levels may affect gonadal function, and melatonin is involved in delaying puberty; concerns about supplemental doses in children should be treated cautiously. 5 6

4. Uncertain supplement dose: Tested products have contained substantially less or more melatonin than their labels indicate, making the actual dose—and its effects—less predictable. 7

5. Caution and alternatives: Light, exercise, and temperature-based behavioral approaches were presented as controllable alternatives for shifting sleep timing. Extra caution was advised for children and adolescents because of possible puberty-related effects, and during pregnancy because melatonin can affect placental development. 8 6 9