Melatonin for Jet Lag: What Works, What Doesn't, and What to Watch For

When you cross time zones, your body’s internal clock gets thrown off—that’s melatonin for jet lag, a natural hormone your body produces to signal sleep, often used as a supplement to reset your sleep-wake cycle after long flights. It’s not a sleeping pill. It’s more like a gentle nudge to tell your brain it’s time to wind down, even if the sun is still up. People use it because it’s available without a prescription, doesn’t leave you groggy the next day like some sleep aids, and has been studied in travelers flying across multiple time zones.

But here’s the thing: circadian rhythm, your body’s 24-hour internal clock that controls when you feel alert or sleepy isn’t just fooled by time changes—it’s also sensitive to light, meals, and activity. Taking melatonin at the wrong time can make jet lag worse. If you’re flying from New York to Tokyo, taking it at 8 p.m. New York time won’t help. You need to take it around 8 p.m. local time in Tokyo, even if it’s only noon where you are. That’s why timing matters more than dosage. Most studies suggest 0.5 to 5 mg, taken 30 to 60 minutes before your target bedtime at your destination.

And it’s not the only tool. jet lag remedies, strategies like controlled light exposure, avoiding caffeine after noon, and staying hydrated work better when combined with melatonin. One 2021 review of 10 trials found travelers who used melatonin + timed light exposure adjusted faster than those who used either alone. Even simple things like walking outside in natural morning light at your destination can help reset your rhythm. But don’t expect magic. If you’re only crossing two time zones, melatonin probably won’t make a noticeable difference. It’s most useful for east-west flights over three or more time zones.

Some people swear by it. Others feel nothing. That’s because everyone’s biology is different. Your age, how often you fly, whether you’re a morning person or night owl—all of it plays a role. And while melatonin is generally safe for short-term use, it can interact with blood thinners, diabetes meds, and immunosuppressants. If you’re on any regular medication, check with your pharmacist before trying it.

Below, you’ll find real-world advice from people who’ve dealt with jet lag after long flights, plus insights on what supplements actually help, what to avoid, and how to sleep better when your body says it’s 3 a.m. but your schedule says it’s 9 a.m. These aren’t guesses. They’re based on clinical observations, patient reports, and what works when you’re tired, stressed, and trying to function on a broken clock.