Melatonin for jet lag: timing and dose determine whether it actually works
Melatonin for jet lag: the timing is everything, and the dose is lower than you'd think
Time to effect
Dose
Active compound
▪ The challenge at hand
Melatonin is one of the most effective jet lag interventions, with a genuine Cochrane review supporting its use, but the details that determine whether it actually works are almost never communicated: timing depends on travel direction, dose should be lower than most people assume, and the first dose timing at your destination is more important than any subsequent dose.
For eastward travel (advancing your clock, the harder direction), melatonin should be taken at bedtime in the new destination to shift your rhythm forward. For westward travel (delaying your clock, the easier direction), the case is weaker. The dose that works is 0.5-3mg, substantially less than the common 5-10mg products in most pharmacies, because high doses produce supraphysiological melatonin levels that may actually disrupt rather than guide the circadian shift you're trying to make.
▪ What it is
Low-dose melatonin (0.5-3mg), taken at bedtime in the destination time zone for 2-4 nights, to signal the circadian clock to phase-shift toward the new local time.
▪ Why this is surprising
Melatonin works for jet lag, but the details are rarely communicated: the timing (which depends on travel direction), the dose (0.5-3mg, far less than the 5-10mg pills most pharmacies sell), and the specific timing at your destination are all critical. High doses produce supraphysiological melatonin that may disrupt rather than guide circadian phase-shifting. The direction-dependence (more helpful for eastward travel, less so for westward) is not on any product label.
▪ How it works
Sending a false dusk signal to the body clock.
Melatonin signals darkness to the circadian clock in the brain. Taking it in the evening at your destination when it's still daytime by your body's internal clock sends a false 'night' signal, accelerating the phase shift of your rhythm toward the new time zone. This works best when taken to advance the clock (eastward travel), since the body naturally has a slightly longer-than-24-hour rhythm and delays are easier than advances.
▪ The research
What the evidence says
A Cochrane systematic review of melatonin for jet lag found it significantly reduces jet lag symptoms when taken at the correct time relative to the destination time zone, with the clearest evidence for eastward travel of 5 or more time zones. Low doses (0.5-3mg) were effective, and higher doses were not demonstrably more effective.
Herxheimer A, Petrie KJ. Cochrane Database Syst Rev. 2002;(2):CD001520. PMID: 12076414.
started
completed
noticed a change
made it routine
▪ What to look for
A practical buying guide
The 0.5mg dose exists and is worth seeking out; in the US, 1mg melatonin is a common starting dose and is found in pharmacies. The 5-10mg products that dominate most pharmacy shelves are higher than the evidence supports for jet lag and may worsen rather than improve the rhythm shift.
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▪ What to expect over time
First dose on the evening of arrival at your destination. Continue for 2-4 nights until your sleep rhythm stabilizes in the new time zone.
Side effects
Drowsiness, headache, dizziness at higher doses. Potential for overshooting the intended phase shift if used at the wrong time.
Who should be cautious
Avoid with seizure disorders. Use caution with blood-thinning medications. Not recommended in pregnant or breastfeeding travelers. Avoid driving or operating machinery within a few hours of taking it. Always consult a care provider when adding or removing a supplement from your routine.
FAQ
Is it better to take melatonin on the plane or at the destination?
I've tried 5mg melatonin for jet lag and it didn't help much. Why?
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Educational only. This is not medical advice. Always talk with a qualified clinician before changing medications, supplements, or care plans.