Sleep · Ingredient guide

Melatonin

Your body's own darkness signal. It tells your brain that night has started, rather than knocking you out like a sleeping pill. That's why it helps most when your body clock is out of step, and least for ordinary trouble sleeping.

What it is

Melatonin is a hormone made every night by the pineal gland, a small gland deep in the brain. It works more like a clock signal than a sedative: rising melatonin tells your body it's time to wind down.

Levels start to rise in the evening, a couple of hours before your usual bedtime, peak in the middle of the night, and fall again in the morning. Light reaching your eyes is the main thing that switches production off.

What throws it off

Evening light. Bright light, especially the blue-rich light from screens and LED bulbs, suppresses melatonin and pushes your clock later.
Crossing time zones. After a long flight, your melatonin still follows home time, so you're sleepy at the wrong hours. This is jet lag.
A late body clock. In some people, melatonin rises much later than usual, so they can't fall asleep until well after midnight.
Shift work. Working at night means trying to sleep when your body isn't making melatonin.
Ageing. On average, night-time melatonin falls with age, partly because the pineal gland gradually calcifies. Healthy older adults vary a lot, though.

Where it helps, and where it doesn't

The same ingredient can work well for one problem and barely at all for another, so we grade each one separately.

A
Jet lag
Large benefit, moderate certainty
Helps your clock switch to the new time zone. Trials used 0.5–5 mg at bedtime at the destination for 2–5 days; higher doses worked no better.
B
Late body clock
Moderate benefit, moderate certainty
Shifted sleep about 40 minutes earlier in trials, but only when taken several hours before bedtime, timed to the body clock. At bedtime it acts only as a mild sleep aid.
C
Ordinary trouble falling or staying asleep
Small to moderate benefit, low certainty
On average people fell asleep about 7 to 10 minutes faster and slept about 8 minutes longer. Real, but small and uncertain, so we don't list products for this.
C
Sleep quality after 55
Small benefit, one specific form
A 2 mg slow-release prescription form helped some older adults. Standard supplements aren't proven to release melatonin the same way.
–
Shift work
Not yet reviewed
We haven't reviewed this evidence yet.

How to use it, based on the evidence

Timing matters more than dose. For jet lag, take it at your new bedtime. For a late body clock, trials gave it hours before bedtime.
Lower doses worked as well as higher ones in jet-lag trials, with less next-day grogginess.
Don't drive for several hours after taking it. Check with a clinician first if you're pregnant, nursing, take medication, or are thinking of giving it to a child.

Helping your own melatonin

Your own melatonin responds strongly to light. Dimming lights and screens in the evening, and getting bright light in the morning, helps it rise at the right time, at no cost.

Listed products

Nature Made Melatonin 3 mg (grade A, jet lag recovery)
Thorne Melaton-3 (grade A, jet lag recovery)