Taking Melatonin for Jet Lag the Right Way
Last reviewed: July 2026
Melatonin is the hormone your body uses to signal to your internal clock that it's nighttime. For jet lag, it can help shift your rhythm faster — but what matters isn't the amount, it's taking it at the right time.
How melatonin works
Melatonin shifts your internal clock similarly to light — just in the opposite direction. Taken in the evening, it makes you tired earlier and moves your rhythm forward; this is mainly used for eastward flights.
Timing for eastward flights
For eastward trips, take a small amount a few hours before your desired new bedtime — this makes you tired earlier and shifts your clock in the right direction. The jet lag calculator marks the right time window for each day.
Timing for westward flights
For westward trips, melatonin is rarely needed since staying awake longer is already easier. If you wake up too early at night, a small amount in the second half of the night can help you fall back asleep.
Dosage and caution
Small amounts are usually enough; more doesn't work better, it's more likely to make you tired during the day. Melatonin isn't a sleeping pill in the classic sense, but a timing cue. When in doubt, check with a doctor before taking it, especially if you take medication, are pregnant, or have pre-existing conditions.
FAQ
When do you take melatonin for jet lag?
For eastward flights, a few hours before your targeted new bedtime; for westward flights, as needed if you wake up at night. The exact window depends on your route — the calculator shows it to you day by day.
How much melatonin makes sense?
Small amounts are enough to shift your rhythm. Higher doses don't shift the clock more strongly, they just increase the risk of daytime sleepiness.
Is melatonin safe?
For short-term use with jet lag, it's considered well tolerated. However, this article doesn't replace medical advice — check with a doctor first if you take medication, are pregnant, or have health conditions.
The science behind it
Flyly's plan is based on the phase-response curve of circadian chronobiology — the same model used in sleep research and space medicine for shift work and time zone changes:
- Lockley & Czeisler — Circadian phase-response curve to light, Harvard Medical School
- NASA Ames Research Center — Circadian rhythm & alertness in aircrew
- Roenneberg et al. — Chronotype & social jetlag, University of Oxford
- Eastman & Burgess — How to travel the world without jet lag, Nature / Sleep Medicine Clinics
