Melatonin

Melatonin is used for the short-term regulation of sleep patterns, including jet lag and insomnia. Research into the use of melatonin supplementation for people affected by seasonal affective disorder, regulation of sleep patterns in people who work late shifts, and the resynchronization of the sleep/wake cycle in people with early Alzheimer disease is currently being evaluated.

Standard dosage is not established and ranges from 0.5 to 5 mg orally taken 1 hour before usual bedtime on the day of travel and 2 to 4 nights after arrival.

Melatonin is also used to manage anxiety before and after surgery; 80% of surgical patients experience anxiety.

Some scientific evidence supports use of melatonin to minimize the effects of jet lag, especially in people traveling eastward over 2 to 5 time zones (1-2 References Melatonin, a hormone produced by the pineal gland, regulates circadian rhythms. It can be derived from animals, but most melatonin is manufactured synthetically. In some countries, melatonin... read more ).

A meta-analysis of 19 studies (1683 subjects) found that in children and adults melatonin for treatment of primary sleep disorders decreases time to fall asleep by 7 minutes, increases overall sleep time by 8 minutes, and improves sleep quality (3 References Melatonin, a hormone produced by the pineal gland, regulates circadian rhythms. It can be derived from animals, but most melatonin is manufactured synthetically. In some countries, melatonin... read more ). One meta-analysis of randomized controlled studies has provided evidence that melatonin decreases sleep onset latency in primary insomnia, benefits patients with delayed sleep phase syndrome, and helps regulate sleep-wake patterns in blind patients (4 References Melatonin, a hormone produced by the pineal gland, regulates circadian rhythms. It can be derived from animals, but most melatonin is manufactured synthetically. In some countries, melatonin... read more ). Another meta-analysis found that melatonin provides benefit for secondary sleep disorders (secondary insomnia caused by sleep restriction)—specifically it reduces sleep onset latency and increases total sleep time, although it does not improve sleep efficiency (5 References Melatonin, a hormone produced by the pineal gland, regulates circadian rhythms. It can be derived from animals, but most melatonin is manufactured synthetically. In some countries, melatonin... read more ).

A Cochrane systematic review of pharmacological interventions for sleepiness and sleep disturbances caused by shift work found low quality evidence that melatonin (1 to 10 mg) after the night shift may increase sleep length during daytime sleep by 24 minutes and night-time sleep by 17 minutes, compared to placebo (6 References Melatonin, a hormone produced by the pineal gland, regulates circadian rhythms. It can be derived from animals, but most melatonin is manufactured synthetically. In some countries, melatonin... read more ).

Evidence supporting use of melatonin as a sleep aid in adults and children with neuropsychiatric disorders (eg, pervasive developmental disorders) is less strong. However, in 19 randomized controlled studies, melatonin significantly improved sleep onset latency, sleep duration, and wake time after sleep onset in children with neurodevelopmental disorders (7 References Melatonin, a hormone produced by the pineal gland, regulates circadian rhythms. It can be derived from animals, but most melatonin is manufactured synthetically. In some countries, melatonin... read more ).

A 2015 Cochrane systematic review included 12 studies that involved 774 people. The review found strong evidence that melatonin is better than placebo at reducing anxiety before surgery. However, the results on melatonin’s benefits for reducing anxiety after surgery were mixed (8 References Melatonin, a hormone produced by the pineal gland, regulates circadian rhythms. It can be derived from animals, but most melatonin is manufactured synthetically. In some countries, melatonin... read more ).

Melatonin content varies in different products (9 References Melatonin, a hormone produced by the pineal gland, regulates circadian rhythms. It can be derived from animals, but most melatonin is manufactured synthetically. In some countries, melatonin... read more ).

Headache, dizziness, nausea, sleepiness, and transient depression may occur. Melatonin may worsen existing depression.

The 2015 guidelines by the American Academy of Sleep Medicine recommend against melatonin use by older people with dementia (10 References Melatonin, a hormone produced by the pineal gland, regulates circadian rhythms. It can be derived from animals, but most melatonin is manufactured synthetically. In some countries, melatonin... read more ). Melatonin may stay active in older people longer than in younger people and cause daytime drowsiness.

A potential adverse effect is unintentional pediatric melatonin ingestion because of its widespread household availability and use (11 References Melatonin, a hormone produced by the pineal gland, regulates circadian rhythms. It can be derived from animals, but most melatonin is manufactured synthetically. In some countries, melatonin... read more ).

Evidence suggests that melatonin may increase the effects of warfarin, increasing the risk of bleeding.

Melatonin may decrease the effects of antiseizure medications and increase the risk of seizures.

Melatonin may enhance the sedative effects of drugs such as benzodiazepines.

Melatonin may increase adverse effects of methamphetamine.

Fluvoxamine, estrogens, and quinolone antibiotics may increase melatonin levels. Carbamazepine and rifampin may decrease melatonin levels.

(See also table .)

The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.