Melatonin for Jet Lag Recovery

Jet lag is the mismatch between the clock in your hypothalamus and the clock on the wall after crossing time zones. Left alone, the body realigns at roughly one time zone per day, which is why a five-hour eastward flight can wreck the best part of a week. Melatonin is the most evidence-supported intervention for accelerating that realignment. A Cochrane review of ten randomised trials found melatonin taken close to target bedtime at the destination reduced jet lag symptoms in eight of them, with benefit greatest on flights crossing five or more zones and travelling east. It is not a sedative strategy. The gains come from delivering a well-timed dusk signal at the destination, which is why dose is secondary and timing is everything.

Direction of travel changes the whole plan. Flying east requires advancing your clock, which melatonin does well when taken in the local evening. Flying west requires delaying it, which is mostly achieved with evening light and a later bedtime, and where melatonin plays a smaller role. For trips of two days or fewer, the sensible strategy is often to stay on home time entirely and skip the adaptation effort altogether.

Light is the dominant time cue reaching the suprachiasmatic nucleus, and melatonin is the internal signal of biological dusk. After a flight, the retina receives light at the wrong internal phase, and endogenous melatonin release stays anchored to the departure time zone. Taking melatonin at destination bedtime superimposes an artificial dusk on the new schedule, acting via MT2 receptors to advance the clock, while MT1 signalling produces enough sleepiness to help sleep occur at a locally appropriate time. Repeated across successive evenings, each dose adds roughly an hour of phase shift, compressing a week of natural drift into a few days. Because the phase response curve is time dependent, the same dose taken at the wrong internal hour can shift the clock in the wrong direction.

The trial protocol that works is simple: take melatonin at local bedtime at the destination, starting on the day of arrival, and repeat for two to five nights until you are sleeping on local time. Some protocols add a dose in the early evening on the last day or two before an eastward flight. Doses between 0.5 and 5 mg all worked in trials, and higher doses were not more effective, only more likely to cause morning grogginess. Immediate release outperformed slow release in a head-to-head comparison, so choose a plain formulation.

The Cochrane review remains the anchor: across ten randomised, placebo-controlled trials in air travellers crossing five or more time zones, melatonin taken close to destination bedtime reduced self-rated jet lag, with the authors describing the effect as remarkably consistent. A separate randomised dosage-form comparison found immediate-release melatonin more effective than slow release for alleviating symptoms. Broader reviews of jet lag place melatonin alongside strategic light exposure and scheduled sleep as first-line, and note that no pharmacological option speeds realignment more reliably. Trial outcomes are subjective ratings rather than hard endpoints, which is the main limitation of the evidence base.

Short courses around travel are well tolerated. The usual complaints are headache, vivid dreams, next-morning heaviness and transient dizziness, all more common at higher doses. Two travel-specific cautions are worth naming. Sedation combined with alcohol on a flight or in an unfamiliar city increases the risk of falls and poor judgement, and product quality varies enough that verified-content brands are worth seeking out. Epilepsy, autoimmune disease, pregnancy and breastfeeding all warrant medical advice before use.

Melatonin is cleared mainly by CYP1A2, so inhibitors of that enzyme raise exposure sharply. Travel-specific combinations matter most: alcohol, sleeping tablets and antihistamines taken to cope with a flight stack sedation on top of melatonin.