Does Melatonin Help With Jet Lag?

What is jet lag, exactly?

Jet lag is what happens when your body's internal clock (circadian rhythm) falls out of step with the local clock at your destination. It is not just tiredness from a long flight — it is a temporary disruption of the internal timing system that regulates sleep, digestion, alertness, and mood. Symptoms include trouble sleeping at night, daytime drowsiness, difficulty concentrating, irritability, and gastrointestinal upset. Most people recover naturally within a few days, but recovery can be faster with the right strategies.

How does melatonin work for jet lag?

Melatonin is a hormone naturally produced by the pineal gland, mainly in response to darkness. Its role is not to sedate you like a sleeping pill — it is a timing signal that tells your body it is night. Taking it at the right time relative to the new time zone can help shift your internal clock earlier or later 1Ref 1Herxheimer A, Petrie KJ (2002).Melatonin for the Prevention and Treatment of Jet Lag.Evidence that melatonin reduces jet lag severity, particularly for eastward travel crossing multiple time zones; timing guidance for use at destination bedtime.

A Cochrane review found that melatonin taken close to the target bedtime at the destination is effective at reducing jet lag for travelers crossing five or more time zones, with the effect being most consistent for eastward travel 1Ref 1Herxheimer A, Petrie KJ (2002).Melatonin for the Prevention and Treatment of Jet Lag.Evidence that melatonin reduces jet lag severity, particularly for eastward travel crossing multiple time zones; timing guidance for use at destination bedtime. For westward travel, the clock-shifting benefit is less clear, though melatonin taken near the target bedtime at the destination may still help with sleep onset.

Low doses appear to be as effective as higher doses for this purpose, and higher doses are more likely to cause next-day grogginess. The range found in supplements varies widely in the United States, where melatonin is not regulated as a drug by the FDA — meaning labeled doses may not reflect actual content.

When should you take melatonin for jet lag?

General practice for eastward travel is to take melatonin in the early evening at your destination's local time — not when you feel like going to sleep by your home clock, but when it is actually evening in the new time zone. Starting on the first evening after arrival and continuing for a few nights is the common approach 1Ref 1Herxheimer A, Petrie KJ (2002).Melatonin for the Prevention and Treatment of Jet Lag.Evidence that melatonin reduces jet lag severity, particularly for eastward travel crossing multiple time zones; timing guidance for use at destination bedtime.

For westward travel, some people find melatonin useful taken near the new local bedtime, particularly if they are waking far too early in the morning.

The right timing depends on direction of travel, number of time zones crossed, and your schedule at the destination. For complex itineraries — or if you also take other medications across time zones — a clinician or travel medicine provider can give more specific guidance. Melatonin is not regulated as a drug in the United States; choosing a product from a brand that uses third-party testing can help with dose consistency.

What other strategies work alongside melatonin?

Melatonin works best as part of a broader approach to resetting your clock:

• Light exposure: Morning light at your destination after eastward travel helps reset your clock 2Ref 2Chang AM, Aeschbach D, Duffy JF, Czeisler CA (2015).Evening Use of Light-Emitting eReaders Negatively Affects Sleep, Circadian Timing, and Next-Morning Alertness.The role of evening light exposure in delaying circadian timing, supporting recommendation to avoid bright screens in evenings when adjusting to a new time zone. Avoid bright light in the evenings for the first few days after arrival. Evening use of light-emitting screens close to bedtime can delay the clock shift 2Ref 2Chang AM, Aeschbach D, Duffy JF, Czeisler CA (2015).Evening Use of Light-Emitting eReaders Negatively Affects Sleep, Circadian Timing, and Next-Morning Alertness.The role of evening light exposure in delaying circadian timing, supporting recommendation to avoid bright screens in evenings when adjusting to a new time zone.
• Sleep timing discipline: Try to go to bed and wake up at your destination's local time, even if it is hard at first.
• Avoid alcohol: Alcohol may help you fall asleep but disrupts sleep architecture and worsens jet lag recovery 3Ref 3Ebrahim IO, Shapiro CM, Williams AJ, Fenwick PB (2013).Alcohol and Sleep I: Effects on Normal Sleep.Alcohol disrupts sleep architecture, worsening recovery from sleep timing disruption such as jet lag.
• Stay hydrated: Long flights cause dehydration, which can compound fatigue and headache.
• Strategic napping: Short naps under 20 to 30 minutes can ease acute fatigue without locking in your home-clock sleep pattern.