Melatonin

What is melatonin?

Melatonin is a hormone made by the pineal gland in the brain. Levels rise in the evening as light fades and fall in the morning, which helps signal the body’s internal clock that it is time to sleep. Melatonin sold as a supplement is usually made in a lab. In the United States it is sold as a dietary supplement, while some other countries treat it as a prescription drug (NCCIH).

What the research says

Melatonin has been studied more than most sleep supplements, but the effects are modest. A 2013 meta-analysis of 19 placebo-controlled trials in people with primary sleep disorders found melatonin shortened the time to fall asleep by about 7 minutes and increased total sleep time by about 8 minutes, with a small improvement in overall sleep quality (Ferracioli-Oda et al., PLoS One). Trials using higher doses and longer durations tended to show larger effects.

The American Academy of Sleep Medicine’s 2017 guideline suggests clinicians not use melatonin as a treatment for sleep onset or sleep maintenance insomnia in adults. This was a weak recommendation, meaning the evidence was limited, not that melatonin never helps (Sateia et al., J Clin Sleep Med). NCCIH notes that melatonin may help with some circadian rhythm problems, such as jet lag and delayed sleep phase, where its timing role is most relevant.

Quality is a concern. NCCIH describes a 2017 analysis of 31 melatonin supplements in which most products did not contain the amount listed on the label, and some contained serotonin. Choosing a product verified by a third party can reduce that risk.

How it’s used in supplements

Melatonin appears alone or in combination sleep formulas, in tablets, capsules, gummies and liquids. Doses on store shelves range from under 1 mg to 10 mg or more. Short-term use appears to be safe for most adults, but long-term safety has not been established. Possible side effects include headache, dizziness, nausea and daytime sleepiness, and melatonin may stay active longer in older adults (NCCIH).

NCCIH advises that people with epilepsy and those taking blood thinners use melatonin only under medical supervision, and there is little safety research in pregnancy or breastfeeding. Emergency visits for children who swallowed melatonin, often gummies, have risen, so store it out of reach. Combining melatonin with sedatives or alcohol may add to drowsiness. For chronic insomnia, cognitive behavioral therapy for insomnia (CBT-I) is the recommended first-line treatment.