Melatonin is a hormone found naturally in the body. Melatonin used as medicine is usually made synthetically in a laboratory. It is most commonly available in pill form, but melatonin is also available in forms that can be placed in the cheek or under the tongue. This allows the melatonin to be absorbed directly into the body.

Some people take melatonin by mouth to adjust the body’s internal clock. Melatonin is most commonly used for insomnia and improving sleep in different conditions. For example, for adjusting sleep-wake cycles in people whose daily work schedule changes (shift-work disorder), and for helping people establish a day and night cycle.

How does it work?

Melatonin’s main job in the body is to regulate night and day cycles or sleep-wake cycles. Darkness causes the body to produce more melatonin, which signals the body to prepare for sleep. Light decreases melatonin production and signals the body to prepare for being awake. Some people who have trouble sleeping have low levels of melatonin. It is thought that adding melatonin from supplements might help them sleep.

Likely Effective for

→ Trouble falling asleep at a conventional bedtime (delayed sleep phase syndrome). Taking melatonin by mouth appears to reduce the length of time needed to fall asleep in young adults and children who have trouble falling asleep. However, within one year of stopping treatment, this sleeping problem seems to return.

→ Non-24-hour sleep wake disorder. Taking melatonin at bedtime seems to improve sleep in children and adults who are blind.

Possibly Effective for

→ Sleep disturbance caused by certain blood pressure medicine (beta blocker-induced insomnia). Beta-blocker drugs, such as atenolol and propranolol, are a class of drugs that seem to lower melatonin levels. This might cause problems sleeping. Research shows that taking a melatonin supplement might reduce problems sleeping in patients taking beta-blocker drugs.

→ Insomnia. Taking melatonin short-term seems to shorten the amount of time it takes to fall asleep in people with insomnia, but only by about 7-12 minutes. Melatonin might also increase the amount of time that a person with insomnia spends sleeping. But results are conflicting, and any benefit is small at best. Some people say melatonin makes them sleep better, even though tests do not agree. There is some evidence that melatonin is more likely to help older people than younger people or children. This may be because older people have less melatonin in their bodies to start with. There is also interest using melatonin for people with insomnia and other conditions.