Sleep

Melatonin is a timing signal, not a sleeping pill

Melatonin tells your body when it is night. Small, well-timed doses can shift your clock, but large doses at bedtime often disappoint.

Melatonin is a hormone made by the pineal gland as darkness falls. Its main job is not to knock you out but to tell the body that night has started, which helps set the timing of sleep, body temperature and many other daily rhythms. That is why melatonin supplements work best for problems of timing, such as jet lag, a body clock that runs very late or shift work, and much less well for ordinary insomnia caused by stress or poor habits.

Research suggests that more is not better. Doses as low as 0.5 to 1 milligram can shift the body clock when taken a few hours before your desired bedtime, while many products sold over the counter contain 5 or 10 milligrams. High doses can leave people groggy the next morning and may cause headaches or vivid dreams. Product quality also varies; in some countries tested supplements contained very different amounts from what the label stated.

If you want to try melatonin, talk to a doctor or pharmacist first, especially if you take other medication, are pregnant, or are considering it for a child. Start low and take it at a consistent time, and combine it with the habits that do most of the work: bright light in the morning, dim light in the evening, a regular wake-up time and avoiding caffeine late in the day. Melatonin can nudge your clock, but it cannot replace a consistent routine.

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