Melatonin — what it is, the right dose, and who it helps
Melatonin isn't a sleeping pill — it's a signaling hormone. Here's what melatonin actually does, who it helps, and what research says about dose and timing.
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Melatonin is the most misunderstood sleep supplement there is. Many people take it like a sleeping pill — a slightly stronger version of warm milk — and are disappointed when it doesn’t knock them out the way a prescription sedative would. That’s because they’ve misunderstood what melatonin actually is and does.
Melatonin isn’t a sleeping pill. It’s a time signal.
What is melatonin?
Melatonin is a hormone produced by the pineal gland in the brain — the small gland Descartes once called “the seat of the soul.” Production happens in darkness and is suppressed by light, particularly blue light.
Melatonin tells the body that it’s night — not that it should sleep. That’s a subtle but important difference. The hormone signals to the body’s biological clock that it’s time to prepare for sleep: core temperature drops, cortisol levels fall, and sleepiness gradually increases. But it isn’t melatonin itself that produces sleep — it’s the cascade of biological processes that melatonin sets in motion.
Regulations vary widely by country. In the United States, melatonin is sold over the counter as a dietary supplement. In the UK and much of Europe, it’s available mainly by prescription. That difference reflects a medical caution worth taking seriously: melatonin is safe when used correctly, but many people use far more of it than they need.
What melatonin actually helps with
Research is clear that melatonin is effective for some conditions and not very effective for others.
It helps with:
Jet lag is the best-documented use case. Melatonin helps the body reset its biological clock faster after crossing time zones — particularly on eastbound trips (where jet lag tends to be worst). The dose is taken at the correct bedtime for the destination.
Delayed sleep phase syndrome — where the biological clock is naturally shifted to want sleep late at night — is another well-documented use. Melatonin taken 1–2 hours before the desired bedtime can gradually shift the sleep phase earlier.
Shift work — a similar problem to jet lag, but chronic.
Sleep problems in older adults — melatonin production naturally declines with age, and supplementation is documented as helpful in people over 55.
It rarely helps with:
Ordinary insomnia in adults, where the problem is rumination, anxiety, or poor sleep hygiene. Melatonin alone is not very effective here.
Chronic sleep deprivation caused by simply not spending enough time in bed. Melatonin isn’t a way to compensate for insufficient sleep time.
The right dose — much lower than you think
The most common mistake with melatonin is taking too high a dose. Many products are sold in doses of 5–10 mg. Research shows that the effective dose for most adults is 0.5–1 mg. Higher doses don’t produce better sleep — they can actually disrupt the biological clock and cause morning grogginess.
Children and teenagers: melatonin is used for autism and ADHD with good supporting evidence, but always under a doctor’s guidance and at low doses.
Timing matters
Melatonin should be taken 30–60 minutes before your intended bedtime — not right before. Since it’s a time signal rather than a sedative, the body needs time to respond to it.
For jet lag: start with a low dose (0.5 mg) at the destination’s bedtime, not your home time zone’s.
Melatonin and your dreams
An interesting side effect many people who take melatonin report: more vivid and intense dreams. This is likely related to melatonin’s ability to enhance REM sleep — the stage in which most dreaming occurs.
Some people experience this as a positive effect (more memorable, interesting dreams); others find it disruptive. If you take melatonin and notice your dreams becoming very intense or unsettling, it can help to lower the dose or take it slightly earlier.
A time signal, not a sedative
Melatonin is a time signal, not a sleeping pill:
- It tells the body it’s night — and sets biological sleep processes in motion
- It’s well documented for jet lag, delayed sleep phase, and sleep problems in older adults
- The effective dose for most people is 0.5–1 mg, far lower than most products contain
- It does little for ordinary insomnia caused by rumination and anxiety
- Timing matters: take it 30–60 minutes before your intended bedtime
Sources and further reading
- Journal of Pineal Research (Cruz-Sanabria et al., 2024) — “Optimizing the Time and Dose of Melatonin as a Sleep-Promoting Drug: A Systematic Review of Randomized Controlled Trials and Dose–Response Meta-Analysis”
- NHS — Sleep and tiredness
- Sleep Foundation — How Sleep Works