The most common options for sleeping on a plane are melatonin, over-the-counter antihistamines, and, in some cases, prescription sleep medications. Each works differently and comes with trade-offs worth understanding before you board, especially since cabin pressure, dehydration, and tight seating change how your body responds to sedatives at altitude.
Melatonin: The Most Widely Used Option
Melatonin is the go-to for many travelers because it nudges your body’s internal clock rather than knocking you out. It’s not a sedative in the traditional sense. Instead, it signals to your brain that it’s time for sleep, which makes it most useful when you’re flying at a time your body wouldn’t normally be sleeping.
A dose of 0.5 to 1 mg is often enough to produce the desired effect. Higher doses (above 5 mg) aren’t more effective and can actually backfire: as the excess melatonin is metabolized, it lingers in your system and may leave you feeling off at the wrong time of day. Take it about 90 minutes before you want to fall asleep on the plane.
Timing matters more than dose. If you take melatonin when your body is already producing it naturally (roughly midnight to 5 a.m. by your home clock), it won’t add much. The real benefit comes when you use it to shift your sleep window. Flying east, take it in the early evening by your destination’s time to push your clock forward. Flying west, take it in the morning by your home time to push your clock back. Getting this wrong can increase the disconnect between your body and the local time rather than fixing it.
Over-the-Counter Antihistamines
The active ingredients in most OTC sleep aids sold at airport pharmacies are first-generation antihistamines, the same compounds found in common allergy medications. They cause drowsiness as a side effect, which is why they’ve been repurposed as sleep aids. They’re intended for short-term use, which makes an occasional flight a reasonable scenario.
The downsides are real, though. Dry mouth is common, and cabin air is already low in humidity, so you may wake up very dehydrated. Cognitive impairment, including fogginess, dizziness, and slowed reaction time, can persist after you land. Many people feel groggy for hours, which is a problem if you need to drive, navigate a new city, or make a connecting flight. If you’ve never tried one before, testing it at home first is a smart move so you know how your body reacts.
Prescription Sleep Medications
Some travelers carry prescription sleep aids for long-haul flights. These are typically recommended only for people who haven’t responded to other approaches, and doctors increasingly hesitate to prescribe them specifically for air travel.
The concerns are practical. Sedatives slow your reaction time and thinking, which is a safety issue if the cabin crew needs passengers to respond quickly during turbulence or an emergency. On flights longer than four hours, heavy sedation increases the risk of blood clots because you’re far less likely to shift position, stand up, or move your legs. A small percentage of people also experience a paradoxical reaction, becoming agitated or aggressive rather than sleepy, which is not something you want to discover mid-flight over the Atlantic.
If you already have a prescription and plan to use it on a plane, avoid combining it with alcohol entirely. That combination intensifies every risk listed above.
Why Alcohol Is a Poor Sleep Aid at Altitude
A glass of wine before you recline your seat might feel like the easiest solution, but the research paints a different picture. A 2024 study from the German Aerospace Center tested what happens when people drink the equivalent of two beers or two glasses of wine and then sleep under simulated cabin pressure. Even in healthy adults aged 18 to 40, blood oxygen levels dropped to around 85% (normal is 95 to 100%), and resting heart rate climbed to about 88 beats per minute during sleep. Deep sleep and REM sleep, the stages your body needs most for recovery, were both reduced.
Airplane cabins are pressurized to the equivalent of roughly 6,000 to 8,000 feet above sea level, so your blood oxygen is already lower than on the ground. Alcohol makes that worse. The result is sleep that feels restless and a body that’s working harder than it should be. If you have any heart or lung condition, the strain is more significant.
Natural Supplements
Magnesium glycinate is frequently mentioned in travel forums as a calming supplement. It’s available in tablets, gummies, and powders, and it’s easy to pack. The recommended daily intake for most adults is 310 to 420 mg depending on age and sex. However, despite widespread marketing claims, magnesium’s effects on sleep and relaxation haven’t been proven in human studies. It’s unlikely to cause harm at normal doses, but you shouldn’t count on it as your primary strategy for sleeping through a red-eye.
Valerian root, lavender capsules, and similar herbal options fall into the same category: generally safe, limited evidence, and effects that vary widely from person to person. They may take the edge off for some travelers, but they’re unreliable as standalone sleep aids.
Getting Through Security With Sleep Aids
Pill-form medications and supplements can go in your carry-on without any special restrictions. If you carry liquid melatonin or a liquid herbal remedy, standard TSA rules apply: containers must be 3.4 ounces (100 milliliters) or less and fit in your quart-sized bag of liquids. Medications are technically exempt from the liquids rule, but having them in their original packaging avoids unnecessary delays at the checkpoint. Any liquid that triggers an alarm during screening will go through additional inspection.
What Actually Helps You Sleep on a Plane
No pill fully compensates for a cramped, noisy, brightly lit environment. The travelers who sleep best on planes combine a mild sleep aid with the right setup. A good eye mask blocks the cabin lights and screen glow that suppress your natural melatonin production. Noise-canceling headphones or earplugs cut engine drone and announcements. A neck pillow keeps your head from falling forward and waking you up repeatedly.
Timing your sleep aid to match when you’d sleep at your destination, rather than just popping something at takeoff, helps your body start adjusting before you land. On a red-eye from the U.S. to Europe, for example, taking 0.5 to 1 mg of melatonin about 90 minutes before European bedtime gets your internal clock moving in the right direction while also helping you sleep during the flight.
Stay hydrated, skip the coffee in the hours before you want to sleep, and get up to move or flex your calves every couple of hours, especially if you’ve taken anything sedating. Blood clots from prolonged immobility are rare but real, and the risk goes up when sedation keeps you completely still for hours at a time.