Posted by Bonita Yonevska
on September 08, 2026
Last updated: 2026-10
Jet lag is what happens when your body clock is still running on home time after you have crossed several time zones. Most people adjust by about one hour per day after flying east and about an hour and a half per day after flying west [1]. The fastest way to beat jet lag is to move light, sleep, meals and caffeine onto destination time, starting a few days before you fly.
What is jet lag, really?
You land in Paris at 7:40 in the morning after an overnight flight from New York. Your phone says breakfast. Your body says it is 1:40 AM and wants to know why you are standing in a passport queue.
That gap is jet lag. A master clock in the brain keeps sleep, hunger, alertness and digestion on a daily schedule, and it does not change time zones when the plane does. The CDC describes the typical picture after crossing at least two time zones: poor sleep at night or heavy sleepiness by day, a general feeling of being unwell, a duller mind and an upset stomach, usually within a day or two of travel [1]. The jet lag remedies that work all reset that clock with light, sleep and meals at the right hour.
Jet lag east vs west: why is flying east harder?
Because the human clock runs a little long. Charles Czeisler and colleagues at Harvard measured its natural cycle at an average of 24.18 hours, in young and older adults alike [2]. Left to itself, your clock drifts slightly later each day.
That makes a later bedtime easy and an earlier one hard. Flying west asks the clock to delay, which is the direction it already leans. Flying east asks it to advance, which works against it. The CDC puts the difference at roughly 1.5 hours of adjustment per day going west and about 1 hour per day going east [1].
Professional sport shows how real the gap is. A team at Northwestern University analysed 20 years of Major League Baseball, 46,535 games from 1992 to 2011, and found that the effects of jet lag were largely evident after eastward travel, with very limited effects after westward travel [3]. Home teams that had just flown east lost 3.5% of their winning percentage, roughly cancelling the 3.9% advantage of playing at home [3].
How do you start adjusting before the flight?
Begin two or three days out. The CDC suggests shifting your sleep by about an hour a day before departure: earlier if you are flying east, later if you are flying west [1]. Move your meals with it. Before New York to Paris, that means lights out at 10 PM, then 9 PM, then 8 PM.
For a trip of less than two days, the CDC advises the opposite: keep sleep, activity and meals on home time [1].
When should you get light, and when should you avoid it?
Bright light in the morning, after the low point of your body clock a few hours before your usual wake up time, pulls the clock earlier. Light in the evening pushes it later [1].
So after flying east, seek bright light in the morning at your destination and keep the evening dim. After flying west, avoid very early morning light, using sunglasses or a closed blind, and get your daylight later in the day [1]. The exact window depends on how many time zones you cross, which is why the CDC points travellers to jet lag calculators [1].
| Flying east | Flying west | |
|---|---|---|
| What the clock has to do | Advance (harder) | Delay (easier) |
| Typical adjustment | About 1 hour per day [1] | About 1.5 hours per day [1] |
| Before you fly | Go to bed an hour earlier each night for 2 to 3 days | Go to bed an hour later each night for 2 to 3 days |
| Light at the destination | Bright light in the morning, dim evenings | Avoid very early light, get daylight later in the day |
| Caffeine | Destination daytime only, none in the 6 hours before bed | Destination daytime only, none in the 6 hours before bed |
Should you sleep on the plane?
Sleep when it is night at your destination. The CDC recommends scheduling sleep, meals and light exposure on the plane by destination time [1]. On an overnight flight to Europe, eat early, skip the film and use an eye mask and earplugs. On a daytime flight west, stay awake. The CDC also advises against sedatives with a long half life [1].
Water, alcohol and caffeine in the air
A drink to help you sleep on board is a popular idea. In a 2024 study from the German Aerospace Center, healthy volunteers slept in a chamber at the reduced air pressure of a long haul cabin, equivalent to 2,438 m. After moderate alcohol, their median blood oxygen saturation during sleep fell to 85.32%, against 88.07% without it, and their heart rate rose. The authors conclude that alcohol combined with cabin conditions reduced sleep quality [4].
The CDC adds that alcohol fragments sleep and that both alcohol and caffeine can contribute to dehydration, which can make jet lag feel worse. Keep drinking water through the flight [1].
Caffeine works best used strategically. On arrival, the CDC suggests caffeine during destination daytime when you need to stay alert, stopping six hours before bed, because caffeine has a half life of about five hours [1]. In a sleep laboratory study, 400 mg of caffeine taken six hours before bedtime still reduced measured sleep by more than an hour, and participants did not notice [5]. Coffee at 5 PM in Paris can cost you the first good night.
Does melatonin help with jet lag?
A Cochrane review by Herxheimer and Petrie looked at randomised trials in travellers and found melatonin taken close to the target bedtime at the destination helpful on flights crossing five or more time zones, with more benefit the more zones crossed and less on westward flights [6]. Daily doses between 0.5 and 5 mg were similarly effective. Timing mattered: melatonin taken early in the day can cause sleepiness and slow adaptation [6]. The CDC notes that 0.5 to 1 mg is often enough and does not recommend more than 5 mg [1].
In the European Union this is one of the authorised health claims. Melatonin contributes to the alleviation of subjective feelings of jet lag. The beneficial effect is obtained with a minimum intake of 0.5 mg to be taken close to bedtime on the first day of travel and on the following few days after arrival at the destination [7].
Your arrival day, hour by hour
After an overnight flight east that lands in the morning:
- On landing: set your watch, your meals and your plans to local time. Stay up until a normal local bedtime.
- Morning: get outside. Walk to breakfast, take the meeting by the window, sit on the terrace.
- Late morning: a Focus strip before the meeting or the museum, while the morning light does its work.
- Early afternoon: your last caffeine of the day, at least six hours before bed [1].
- Evening: dinner at local time, lights low, screens dimmed.
- Bedtime: one Z-z-Zen strip 20 to 30 minutes before sleep, close to local bedtime.
Repeat the evening for the next few nights. Flying back west is usually the easier leg.
Where the Travel Pack fits
The Smart Strips Travel Pack brings together three formulas for a trip across time zones: Z-z-Zen for the nights, Focus for the days and Immune as a daily habit. Each is an oral dissolvable strip that melts on your tongue in 7 to 30 seconds, with no water. Useful on a plane or in a hotel room at 2 AM, as explained in how to take supplements without water.
Z-z-Zen contains 14 mg saffron extract, 12 mg L-glycine, 12 mg L-theanine and 1 mg melatonin per strip. That is twice the 0.5 mg minimum in the EU condition, so take it 20 to 30 minutes before sleep, close to local bedtime, on the first day of travel and for the next few nights after you arrive. The full formula is explained in inside the Z-z-Zen sleep formula.
Focus is for the first mornings. Each strip contains 20 mg Alpha-GPC, 20 mg caffeine, 10 mg L-theanine, 10 mg citicoline and 5 mg phosphatidylserine. Twenty milligrams is a small, measured dose that fits the daytime only rule. Count it alongside any coffee.
Immune contains 20 mg vitamin C, 35 µg vitamin D3 and 20 mg elderberry juice concentrate per strip. Vitamin C contributes to the normal function of the immune system. Vitamin D contributes to the normal function of the immune system [7]. One strip a day fits easily into a travel routine, before and after the flight.
Every Smart Strips formula uses our QuickRelease™ film, and the format delivers up to 95% bioavailability, up to 4x faster absorption and up to 30% higher effectiveness than a swallowed tablet, capsule or powder. How that works is on our science page, and the best moments in the day for each formula are in when to take supplements.
The Travel Pack is one part of the only oral strip range that covers the whole day: training, recovery, focus, stress, sleep, immunity, longevity, beauty, the morning after a night out and intimacy. See the full range.
How Smart Strips are made
Smart Strips are made in the USA, in an FDA registered, cGMP certified facility certified to NSF/ANSI 455-2. Every formula is tested by independent ISO 17025 accredited laboratories for identity, purity and content. If oral films are new to you, start with what oral dissolvable strips are.
When to talk to your doctor
Jet lag settles as your clock catches up. If your sleep stays disrupted long after you have adjusted to the new time zone, or you fly often and it keeps happening, talk to your doctor. Z-z-Zen contains melatonin and may cause drowsiness, so do not drive after taking it, including on the night you pick up a rental car. Focus contains 20 mg of caffeine per strip. Smart Strips are not for children or for pregnant or nursing women. If you take medication, including blood thinners, or have a medical condition such as epilepsy, check with your doctor before using melatonin [6].
FAQ
How do you get over jet lag fast? Move your schedule toward destination time two or three days before you fly, sleep on the plane only when it is night at your destination, get daylight at the right hours on arrival, keep caffeine to the daytime and stop six hours before bed.
Why is jet lag worse when you fly east? The human body clock runs slightly longer than 24 hours, so it delays more easily than it advances. Flying east forces it to advance, and most people adjust by only about one hour per day.
How long does jet lag last? As a rule of thumb, about one day per time zone crossed when flying east and a little less when flying west, where the clock adjusts by about an hour and a half per day.
Does melatonin help with jet lag? Melatonin contributes to the alleviation of subjective feelings of jet lag. The beneficial effect is obtained with a minimum intake of 0.5 mg to be taken close to bedtime on the first day of travel and on the following few days after arrival at the destination.
Is it a good idea to drink alcohol on a long flight to help you sleep? In a 2024 study at simulated cabin pressure, moderate alcohol lowered blood oxygen during sleep, raised heart rate and reduced sleep quality. Water is the better choice.
What is in the Smart Strips Travel Pack? One box each of Z-z-Zen for the nights, Focus for the days and Immune as a daily habit. Each strip dissolves on the tongue in 7 to 30 seconds, with no water.
Sources
- Riedy SM, Williams SG. Jet Lag Disorder. In: CDC Yellow Book 2026: Health Information for International Travel. US Centers for Disease Control and Prevention. cdc.gov/yellow-book/hcp/travel-air-sea/jet-lag-disorder.html
- Czeisler CA, Duffy JF, Shanahan TL, Brown EN, Mitchell JF, Rimmer DW, Ronda JM, Silva EJ, Allan JS, Emens JS, Dijk DJ, Kronauer RE. Stability, precision, and near-24-hour period of the human circadian pacemaker. Science. 1999;284(5423):2177. doi.org/10.1126/science.284.5423.2177
- Song A, Severini T, Allada R. How jet lag impairs Major League Baseball performance. Proceedings of the National Academy of Sciences. 2017;114(6):1407-1412. doi.org/10.1073/pnas.1608847114
- Trammer RA, Rooney D, Benderoth S, Wittkowski M, Wenzel J, Elmenhorst EM. Effects of moderate alcohol consumption and hypobaric hypoxia: implications for passengers' sleep, oxygen saturation and heart rate on long-haul flights. Thorax. 2024;79(10):970. doi.org/10.1136/thorax-2023-220998
- Drake C, Roehrs T, Shambroom J, Roth T. Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. Journal of Clinical Sleep Medicine. 2013. doi.org/10.5664/jcsm.3170
- Herxheimer A, Petrie KJ. Melatonin for the prevention and treatment of jet lag. Cochrane Database of Systematic Reviews. 2002;(2):CD001520. doi.org/10.1002/14651858.CD001520
- Commission Regulation (EU) No 432/2012 establishing a list of permitted health claims made on foods. eur-lex.europa.eu/eli/reg/2012/432/oj
