Melatonin for jet lag: when to take it east vs west

Why direction changes the answer

Eastbound travel asks your body to fall asleep and wake earlier than usual, called a phase advance. Westbound travel asks it to stay awake and wake later, called a phase delay. Most people naturally delay more easily than they advance, which is why flying east often feels harder.

Melatonin taken in the early evening can encourage an earlier body clock. Taken too early in the day or late in the morning, it can shift the clock in the opposite direction. Always schedule it by the time at your destination, not the time at home.

Eastbound flights: timing melatonin

On an eastbound trip crossing three or more time zones, aim to take melatonin 30–60 minutes before your planned destination bedtime. If you land in the morning, stay awake until a normal local bedtime rather than taking melatonin after arrival.

1. Set your target bedtime in the destination time zone.
2. Take a low dose 30–60 minutes before that bedtime.
3. Dim screens and room lighting during the final two hours before bed.
4. Seek outdoor light soon after waking at the destination.
5. Repeat for two to four nights if needed.

Example: flying New York to Paris, plan for sleep around 10:30 p.m. Paris time. Take melatonin around 9:30–10:00 p.m. local time, then get outdoor morning light after waking.

Westbound flights: use it selectively

Westbound travel usually calls for staying awake later. Afternoon and early-evening light at your destination often does more of the work. Melatonin may still help if you wake too early or cannot settle at local bedtime, but taking it early can work against the delay your body needs.

If you use it, take a low dose 30–60 minutes before the bedtime you want at the destination. Avoid taking it during the local afternoon. Seek late-afternoon daylight, keep your first evening gently active, and avoid bright light if you wake before dawn.

How much melatonin should you take?

A larger dose is not automatically more effective. For many adults, 0.5–1 mg provides a useful clock signal with less next-day grogginess. Some products contain 3–5 mg or more; higher doses can remain in the body longer and may cause vivid dreams, headache, dizziness, or morning sleepiness.

Product strength and purity vary by country. Choose a reputable, independently tested product where available. Do not test melatonin for the first time on an important travel night—try it at home when you do not need to drive early the next morning.

Light, caffeine, and naps matter too

Melatonin works best as one part of a schedule. Light is the strongest signal for the body clock. Morning light generally moves sleep earlier; evening light generally moves it later. Use caffeine early in your destination day and stop at least six hours before bedtime. If you must nap, keep it to 20–30 minutes so you preserve sleep pressure for the night.

Who should ask a clinician first?

Speak with a qualified healthcare professional before using melatonin if you are pregnant or breastfeeding, under 18, have an autoimmune or seizure disorder, or take anticoagulants, sedatives, diabetes medication, blood-pressure medication, or other medicines that may interact. Never combine it with alcohol, and do not drive after taking it. This guide is general education, not personalized medical advice.