What Can I Take to Sleep on a Plane: Best Aids

Melatonin is the most broadly studied and accessible sleep aid for air travel, with strong evidence that doses between 0.5 and 5 milligrams taken near your destination bedtime help you fall asleep faster and adjust to new time zones. But melatonin is far from the only option, and the best choice depends on how long your flight is, whether you need to function immediately after landing, and how your body responds to the unique stresses of a pressurized cabin at altitude. The range of things people reach for spans supplements, antihistamines, herbal remedies, and prescription medications, each with trade-offs worth understanding before you board.

Why Sleeping on a Plane Is Harder Than It Seems

Before choosing a sleep aid, it helps to understand why the cabin environment works against you. Aircraft cabins are typically pressurized to the equivalent of about 6,000 to 8,000 feet above sea level. At that simulated altitude, your blood oxygen saturation drops. A controlled study simulating flight-level cabin pressure found that participants spent roughly 70% of their sleep time in a mildly hypoxic state, with blood oxygen dipping below 90%.¹ That same study found that total sleep time at altitude was about 11 minutes shorter than in a normal sleep lab, and deep sleep specifically dropped by close to 18 minutes. Mild oxygen deprivation fragments sleep and reduces its most restorative stages, so even if you do doze off, the quality suffers.

Add in engine noise that typically runs 75 to 85 decibels, cabin lighting controlled by the airline rather than your circadian clock, a seat that barely reclines, and the subtle vibration of the fuselage, and your body faces a long list of reasons to stay awake. Any sleep aid you choose is fighting against all of these factors at once.

Melatonin Is the Strongest Over-the-Counter Option

Melatonin is a hormone your brain produces naturally as light fades, signaling that it is time to sleep. Taking it as a supplement does two things at once: it nudges your circadian clock toward a new time zone, and it has a mild direct sedative effect that makes falling asleep easier. A large Cochrane review pooling data from ten randomized trials found that melatonin taken near the target bedtime at your destination reduced jet lag in flights crossing five or more time zones, with doses between 0.5 and 5 milligrams performing similarly.² People who took a 5-milligram dose fell asleep faster and reported better sleep quality than those taking 0.5 milligrams, but going above 5 milligrams did not add further benefit.

Timing matters more than dose. Taking melatonin close to 10 p.m. to midnight at your destination time is the sweet spot. Taking it earlier in the day can actually cause drowsiness at the wrong time and delay your adjustment to local time.² This is a common mistake: travelers pop melatonin as soon as they board a daytime departure and end up groggy without any circadian benefit. If your flight is an overnight red-eye heading east, melatonin at the local bedtime of your destination city works well. If you’re flying during the daytime, melatonin is better saved for your first night at the destination rather than used mid-flight.

One practical detail that often gets overlooked: slow-release melatonin formulations appear less effective than standard immediate-release tablets. The Cochrane review found that a 2-milligram slow-release dose underperformed, suggesting that a brief, sharp peak in melatonin concentration works better than a low sustained trickle.² So if you’re buying melatonin specifically for travel, look for the regular kind, not the extended-release version.

For very long routes crossing eight or more time zones, some researchers suggest starting melatonin two to three days before departure to begin shifting your internal clock ahead of time.³ For shorter trips across fewer time zones, a single dose at bedtime after arrival is usually enough.

Over-the-Counter Antihistamines and Why Caution Is Warranted

Diphenhydramine (the active ingredient in Benadryl and many drugstore sleep aids like ZzzQuil) and doxylamine (found in Unisom SleepTabs) are probably the most commonly used sleep aids on planes, largely because they are cheap, legal everywhere, and available without a prescription. They work by blocking histamine receptors in the brain, which produces drowsiness as a side effect.

The problem is that “drowsy” and “well-rested” are not the same thing. First-generation antihistamines reduce REM sleep, which is the phase most closely tied to memory consolidation and mental restoration.⁴ You may pass out for several hours but wake up feeling foggy and disoriented, a state sometimes called the “antihistamine hangover.” That hangover can last well into the next day, impairing your ability to drive, navigate a foreign airport, or think clearly at a meeting.

There are also safety concerns that go beyond grogginess. A review by an international allergy research network found that first-generation antihistamines impair learning, reduce work efficiency, and have been implicated in civil aviation and motor vehicle accidents.⁴ For most healthy adults taking a single dose on a long-haul flight, the risk of a serious adverse event is low. But if you need to drive upon landing, or if you’re traveling with children, the calculus changes. These medications are particularly risky for young children and older adults, and many pediatric sleep specialists discourage their use for sedating kids on flights.

If you do use diphenhydramine or doxylamine, the practical advice is to take it only on flights where you have at least seven to eight hours before you need to be alert, and to test it at home first to see how your body responds.

Prescription Sleep Medications

For travelers who struggle with transient insomnia despite melatonin or over-the-counter options, some doctors prescribe short-acting hypnotics. Zolpidem (sold as Ambien) is the most commonly prescribed in this category and has been shown to have sedative-hypnotic properties in situational insomnia, the kind triggered by stress, unfamiliar environments, or jet lag, without drastically impairing next-day performance in most people. The key word is “most.” Individual reactions vary, and zolpidem has a well-documented track record of causing sleepwalking, confusion, and amnesia in some users, especially at higher doses or when combined with alcohol.

The short-acting formulation of zolpidem lasts roughly four to five hours, which is a decent match for a nap on a long-haul flight but not ideal for a full night of sleep in the air. Extended-release versions last longer but carry a higher risk of morning grogginess. Other prescription options include zaleplon (Sonata), which has an even shorter duration of about two hours and is sometimes used for mid-flight awakenings, and suvorexant (Belsomra), a newer class of drug that works by blocking wake-promoting signals rather than sedating the brain directly.

Prescription sleep aids generally require a conversation with your doctor before travel. They are not something to try for the first time at 35,000 feet. Side effects, interactions with altitude-related hypoxia, and the potential for disorientation in an unfamiliar environment all make a test run at home essential. Benzodiazepines like lorazepam or diazepam are sometimes used for flight anxiety that prevents sleep, but they carry a higher risk of dependence, residual sedation, and rebound insomnia than the newer alternatives.

Herbal Supplements and L-Theanine

Valerian root is the herbal remedy with the longest research track record for sleep. A systematic review and meta-analysis found that people who took valerian were roughly 80% more likely to report improved sleep quality compared to placebo, though the authors flagged possible publication bias in that estimate.⁵ The side-effect profile is mild, which is valerian’s main selling point. However, valerian has a significant practical limitation for travelers: its sleep-improving effects appear to build over two to three weeks of regular use, making it poorly suited for one-off travel situations like a single long-haul flight.⁶ If you’re a nervous flyer who already takes valerian nightly, it is reasonable to continue taking it on travel days. But buying a bottle at the airport and expecting it to knock you out that night is unlikely to work.

L-theanine, an amino acid found naturally in green tea, has attracted interest as a gentle sleep aid. An animal study found that both L-theanine and a magnesium-L-theanine compound increased sleep duration and reduced the time it took to fall asleep, with the magnesium-bound form showing the strongest effect.⁷ The human evidence is thinner, and doses used in supplements (typically 100 to 400 milligrams) are far higher than what you would get from a cup of tea. L-theanine’s appeal for travel is that it promotes relaxation without heavy sedation. You are unlikely to wake up feeling drugged, but you are also unlikely to sleep through turbulence. A broader review of herbal sleep supplements noted that while valerian, hops, and melatonin show the most promise, optimal doses and formulations remain unsettled for most botanicals.⁸

Other herbal options you will see marketed for travel sleep include chamomile, passionflower, and lavender. The evidence for all three is weaker than for valerian or melatonin, often based on small studies or traditional use rather than randomized trials. They are generally harmless, but “harmless” and “effective” are different things.

The Seat Problem Is Bigger Than You Think

No pill fully compensates for the ergonomic nightmare of economy-class seating. A study examining how backrest angle affects neck comfort during sleep found a counterintuitive result: a reclined backrest at 110 degrees actually caused greater head-and-neck rotation and more muscle fatigue than a nearly vertical seat. The explanation is that reclining pushes your lower body forward while your head, unsupported above the seatback, rolls to one side or drops forward, stretching neck muscles asymmetrically. Taller passengers had it worse because more of their head extended above the top of the backrest. The researchers concluded that without proper head support, reclining may increase rather than reduce neck strain during sleep.

This finding has real implications for your sleep-aid strategy. A travel pillow that stabilizes your head and prevents lateral rolling is likely to improve sleep quality more than upgrading from a 3-milligram melatonin to a 5-milligram dose. U-shaped neck pillows are the most common, but many travelers report better results with wraparound designs or pillows that rest against the window and support the temple. The goal is to prevent your head from falling into positions that wake you up or leave you with a stiff neck. If you are tall, head support becomes even more important because standard seatbacks will not reach the base of your skull.

Staying Still Too Long Carries Its Own Risk

One underappreciated issue with sleeping on a plane, especially with the help of a sedative, is that deep, motionless sleep in a cramped seat increases your exposure to venous stasis, the sluggish blood flow in your legs that can contribute to blood clots. A case-control study examining flight-related behavior and venous thrombosis found that sleeping during a flight was associated with a modestly elevated risk.⁹ The absolute risk for a healthy person on a single flight remains low, but it rises with flight duration, dehydration, and individual risk factors like a history of clots, recent surgery, pregnancy, or use of hormonal contraceptives.

This does not mean you should avoid sleeping on a plane. It means that if you take a sedative strong enough to keep you knocked out for seven or eight hours without moving, you should think about countermeasures. Compression socks are the simplest: knee-high graduated compression stockings reduce leg swelling and improve venous return. Choosing an aisle seat lets you get up without climbing over seatmates. And if you do take a sedative, consider one that wears off partway through the flight so you naturally wake, shift position, and walk for a few minutes before dozing off again.

Matching the Aid to the Flight

Not every flight calls for the same approach. A three-hour domestic hop has very different needs than a fourteen-hour transpacific crossing, and the best aid depends on context.

• Short flights (under 4 hours): A sleep aid is rarely worth it. You will spend most of your limited time either ascending or descending, with seatbelt signs on. If you want to nap, a travel pillow, eye mask, and earplugs are more useful than any supplement. Melatonin’s circadian-shifting effect is irrelevant for a short domestic trip where you stay in the same time zone.
• Medium-haul flights (4 to 8 hours): A low dose of melatonin (3 to 5 milligrams) about 30 minutes before you want to sleep works well if the flight is timed to your destination’s nighttime. Diphenhydramine is an option but risks leaving you foggy at arrival. L-theanine can take the edge off anxiety without heavy sedation.
• Long-haul red-eyes (8+ hours, overnight): This is where melatonin shines, particularly if you’re crossing five or more time zones eastward. A prescription hypnotic like short-acting zolpidem may be justified if you consistently fail to sleep on planes despite other measures, but get up and move at least once during the flight.
• Ultra-long-haul (14+ hours): Consider splitting your sleep into two blocks rather than trying to sedate yourself for the entire flight. Take melatonin or a mild aid for a four-to-five-hour first sleep, then stay awake for a couple of hours, walk around, eat, and let yourself naturally drowse for a second stretch. This reduces blood-clot risk and avoids the prolonged grogginess of a heavy sedative.

What About Alcohol

The drink cart is the most popular sleep aid on planes, and it is also the worst. Alcohol does make you drowsy initially, but it fragments sleep in the second half of the night, suppresses REM sleep, and worsens dehydration in an already dry cabin environment. At cabin altitude, alcohol’s effects are amplified because your blood oxygen is already lower than normal. The combination of altitude-related hypoxia and alcohol-induced respiratory depression means you get less oxygen during sleep than you would drinking the same amount at sea level. You may fall asleep quickly after a glass of wine, but you will wake up more often, feel worse upon landing, and take longer to adjust to the new time zone. Mixing alcohol with any sedative medication, including diphenhydramine, multiplies these risks and can cause dangerous respiratory depression.

Building a Travel Sleep Kit

The most effective approach combines a mild pharmacological nudge with environmental control. A reasonable travel sleep kit for a long-haul flight looks something like this: 3 to 5 milligrams of immediate-release melatonin, timed to your destination bedtime; a comfortable eye mask that blocks light completely; foam or silicone earplugs or noise-canceling headphones; a travel pillow that actually supports your head rather than just your neck; and loose, comfortable clothing. Compression socks are a smart addition for any flight over six hours. Skip the alcohol. Drink water instead.

If you fly frequently for work and routinely struggle to sleep despite these basics, that is a reasonable conversation to have with your doctor about a short-acting prescription option. But for the occasional long-haul trip, melatonin combined with good sleep hygiene in the air works for most people, and it comes without the hangover, dependency risk, or safety concerns of stronger alternatives.