When you land in Tokyo after a 14-hour flight from London, your body still thinks it’s 3 a.m. Even if you’re exhausted, you can’t sleep. You wake up at 2 a.m. local time, wide awake, heart racing. You’ve got a meeting in two hours. This isn’t just tiredness-it’s jet lag, and it’s not something you can outsleep. Most people reach for melatonin, thinking more is better. But if you’re taking a time-released version, you might be making it worse.
Why Jet Lag Isn’t Just About Being Tired
Jet lag isn’t caused by flying. It’s caused by your internal clock being out of sync with the world outside. Your body runs on a 24-hour rhythm-when to sleep, when to wake, when to digest food, when to feel alert. When you cross three or more time zones quickly, that rhythm gets scrambled. The American Academy of Sleep Medicine says symptoms last about 1 to 1.5 days for every time zone crossed. Eastward trips (like London to New York) are harder because you’re losing hours-you have to fall asleep earlier than your body wants. Westward trips (like New York to London) are easier because you’re gaining hours-you can stay up later, and your body doesn’t fight it as hard.The Melatonin Myth: Time-Released Isn’t Better
Melatonin is a hormone your brain makes naturally at night. It tells your body it’s time to sleep. For jet lag, it’s not about helping you fall asleep-it’s about shifting your clock. The key is timing. Take it too early or too late, and you’ll confuse your body even more. Here’s the problem: time-released melatonin stays in your system for 6 to 8 hours. That’s way too long. Your body needs a sharp, short signal-not a slow drip. The CDC’s 2024 guidelines say it clearly: slow-release melatonin is not recommended for jet lag. Why? Because it keeps your melatonin levels high during daylight hours, when your body should be producing zero. That’s like turning on a light in the middle of the night when your body’s trying to wake up. A 2019 study in Sleep Medicine found that 3 mg of immediate-release melatonin taken at 10 p.m. local time shifted your clock by 1.8 hours. The same dose in time-released form? Only 0.6 hours. That’s a 67% drop in effectiveness. For eastward travelers-who need to shift their clock earlier-this means you’re not adjusting fast enough. A 2021 study showed 68% of people using time-released melatonin felt worse, not better.What Works: Immediate-Release Melatonin
Immediate-release melatonin hits your bloodstream fast and clears out in about an hour. That’s perfect. It gives your body a clean, precise signal: it’s bedtime now. The right dose? Between 0.5 mg and 3 mg. Surprisingly, 0.5 mg works just as well as 5 mg for shifting your clock, according to a 2002 review in The Lancet. Higher doses might help you fall asleep faster, but they don’t help your rhythm adjust better. For eastward travel (e.g., flying to Asia): take 0.5-3 mg of immediate-release melatonin 30 minutes before your target bedtime at your destination. Start this 2-3 days before you fly if you can. For a 9-hour time difference, take it at 10 p.m. destination time for 4-5 nights. The Mayo Clinic and CDC both recommend this. Don’t take it after midnight-that’s when your body is naturally waking up. You’ll just delay your adjustment. For westward travel (e.g., flying to Europe): you want to delay your clock. The best way is to get bright light in the morning and avoid it in the evening. Melatonin isn’t as useful here, but if you want to try, take 0.5 mg when you wake up at your destination. This is less common and less studied, but some travelers report success.Why Time-Released Melatonin Is Still Sold
You’ll find time-released melatonin everywhere-Amazon, Walmart, pharmacies. It’s marketed as “all-night sleep support.” That’s fine for people with insomnia who struggle to stay asleep. But jet lag isn’t about staying asleep. It’s about resetting your clock. The European Medicines Agency approved a time-released melatonin product called Circadin-but only for insomnia in adults over 55. They specifically said it’s not for jet lag. The FDA doesn’t regulate melatonin as a drug at all. That means labels can be wildly inaccurate. One FDA warning in 2023 found melatonin supplements contained 83% to 478% more than what was listed on the bottle. Most travelers don’t know the difference. They see “time-released” and think it’s more advanced. It’s not. It’s the wrong tool for the job.
Real People, Real Results
On Reddit’s r/Biohackers, 78% of users who tried time-released melatonin for jet lag said they felt groggier and took longer to adjust. A 2023 survey of over 5,000 frequent flyers found those using time-released melatonin took 2.4 days longer to adapt than those using immediate-release. One user wrote on Amazon: “Took it for my Tokyo trip. Woke up at 3 a.m. feeling wired. Felt like I had a hangover for two days.” Another said: “I accidentally took the time-release version once. I was disoriented for two full days. The immediate-release version? I was back to normal in 3.5 days.” Business travelers are catching on. Forty-two of the Fortune 100 companies now give employees immediate-release melatonin and timing instructions before international trips. None recommend time-released versions.Timing Matters More Than Dose
Even the right melatonin won’t work if you take it at the wrong time. A 2022 study from the University of Surrey found 65% of people mis-timed their doses by two or more hours. That’s like trying to set a watch with a blindfold on. Use a tool. The Timeshifter app, used by over 1.2 million travelers, calculates your ideal melatonin time based on your flight, sleep habits, and chronotype. It’s not perfect, but it’s better than guessing. You can also use free online calculators from sleep clinics. The key is to match your dose to your destination’s clock-not your home clock.What Else Helps? Light and Routine
Melatonin isn’t magic. It works best with light. Get bright light (natural sunlight or a 10,000-lux lightbox) in the morning after eastward travel. Avoid blue light from screens after taking melatonin. Stay hydrated. Avoid alcohol and caffeine right after landing. Try to sleep and wake at local times-even if you’re exhausted. Force your body into the new rhythm.
What About Other Medications?
Some people turn to sleeping pills like zolpidem or stimulants like modafinil. These help you sleep or stay awake, but they don’t fix your clock. You’ll still feel off for days. Melatonin is the only thing that actually resets your internal rhythm. The American Academy of Sleep Medicine gives it a strong recommendation for eastward travel. Nothing else does.The Future of Jet Lag Treatment
Researchers are looking at genetic markers to predict who responds best to melatonin. Early studies show people with certain gene variants need to take it hours earlier or later than average. The NIH is funding trials to build personalized timing algorithms. In the meantime, the market is shifting. Time-released melatonin for jet lag is expected to drop to under 5% of sales by 2030. Immediate-release will remain the standard.Bottom Line: Skip the Time-Released
If you’re flying across time zones and want to feel normal faster, use immediate-release melatonin. Take 0.5-3 mg 30 minutes before your target bedtime at your destination. Start 2-3 days before you fly. Avoid time-released versions-they’re designed for the wrong problem. Combine it with bright light in the morning and darkness at night. Don’t rely on guesswork. Use an app. And remember: your body isn’t broken. It’s just out of sync. With the right timing, it’ll catch up.Is time-released melatonin safe for jet lag?
It’s not unsafe in the sense of causing harm, but it’s ineffective for jet lag. Time-released melatonin keeps melatonin levels elevated for 6-8 hours, which confuses your circadian clock. The CDC and American Academy of Sleep Medicine explicitly advise against it for jet lag because it delays adaptation. You’re not helping your body reset-you’re interfering with it.
What dose of melatonin should I take for jet lag?
Start with 0.5 mg. Research shows this is just as effective as higher doses for shifting your circadian rhythm. If you need help falling asleep, you can go up to 3 mg. But don’t take more than that. Higher doses don’t improve rhythm adjustment-they just make you groggy. The key is timing, not quantity.
When should I take melatonin for eastward travel?
Take it 30 minutes before your target bedtime at your destination. For example, if you’re flying from London to Tokyo (9-hour difference), your target bedtime is 10 p.m. Tokyo time. Take the melatonin at 9:30 p.m. Tokyo time. Do this for 4-5 nights after arrival. Don’t take it after midnight-it will push your clock backward instead of forward.
Can I use melatonin for westward travel?
It’s less effective. Westward travel means you’re gaining hours, so your body naturally wants to stay up later. The best strategy is to get bright light in the morning and avoid light in the evening. If you use melatonin, take 0.5 mg when you wake up at your destination. This can help delay your clock slightly, but light exposure is more important.
Are melatonin supplements regulated?
In the U.S., melatonin is sold as a dietary supplement, not a drug. That means the FDA doesn’t check for accuracy or purity. A 2023 FDA warning found some products contained 83% to 478% more melatonin than labeled. Stick to reputable brands with third-party testing (like USP or NSF certified). In Europe, melatonin is prescription-only in some countries, but not for jet lag.
Comments (1)
Tim Tinh December 9 2025
just took the time-released stuff for my trip to Tokyo last month and woke up at 3am feeling like my brain was stuffed with cotton and my eyes were on fire. i thought it was ‘advanced’ or something. turns out i was just poisoning my own circadian rhythm. immediate-release 0.5mg at 10pm local? game changer. slept like a baby by day 3.