By Elina Ivanova-Atanassov, Founder and CEO, Smart Strips · Last updated: November 2026
You land in Sofia at eleven in the morning after the overnight flight from New York. Lunch goes well. By four in the afternoon you are reading the same line of an email for the third time, and at three the next morning you are wide awake in a dark hotel room, perfectly alert, seven hours ahead of your own body.
That is jet lag, and it has a predictable pace. According to the CDC, the body clock adapts at an average of about 1 hour a day after flying east and about 1.5 hours a day after flying west (Riedy and Williams, 2025). The fastest way through it is to give the clock the right signals at the right local time: light, sleep and, for the first nights, a low dose of melatonin. This guide sets out that plan, and where Smart Strips Z-z-Zen and the Travel Pack fit into it.
What is jet lag, exactly?
Jet lag is the gap between the clock in your body and the clock on the wall after you cross time zones quickly. The CDC describes jet lag disorder as linked to travel across at least two time zones, and lists sleep disturbances, cognitive impairment, daytime sleepiness and general malaise among its signs (Riedy and Williams, 2025).
The cause is a master clock in the brain that runs on roughly a day and resets itself mainly from light. A review of light and circadian rhythms describes ambient light as the most important time cue that reaches this clock (Blume et al., 2019). A plane can move you across seven time zones in nine hours. The clock follows at its own speed.
Why is flying east harder than flying west?
Because most people find it easier to stay up later than to fall asleep earlier. In the CDC's words, "for most people, it is easier to delay than advance the circadian rhythm." Flying west asks the clock to delay. Flying east asks it to advance.
The average rates make the difference concrete: about 1.5 hours a day westward and 1 hour a day eastward (Riedy and Williams, 2025). New York to Sofia is seven time zones east, so at that average pace the body needs around a week to catch up fully. Sofia to New York, the same seven zones in the other direction, takes closer to five days.
The number of time zones matters too. Two or three zones are usually a matter of one or two heavy evenings. The Cochrane review of melatonin for jet lag focused on flights across five or more time zones, where the effect on how people feel is largest (Herxheimer and Petrie, 2002).
How do you use light to adjust faster?
Light is the strongest tool you have, and timing decides which way it pushes the clock. Morning light advances the clock, while evening and night light delays it (Blume et al., 2019).
After flying east. The CDC advises getting bright light in the early morning, with the blinds open and without dark sunglasses, and avoiding light in the evening. In practice: breakfast by the window, a walk before your first meeting, dim lights and no bright screens late at night.
After flying west. Here the advice reverses at the start of the day: avoid bright light in the early morning, and keep yourself in daylight through the afternoon and early evening, when you are most tempted to sleep.
Outdoor light is far stronger than indoor light. Full daylight reaches about 25,000 lux, while standard office lighting is around 500 lux (Blume et al., 2019). Ten minutes outside does more for the clock than an hour in a bright lobby.
What should you do on the plane?
Set your watch to the destination as you board, and start living on that time where you can.
Sleep when the destination sleeps. If it is night where you are going, an eye mask and earplugs help. If it is daytime there, a short nap is fine, and the rest of the flight is better spent awake.
Drink water and go easy on alcohol. The CDC notes that volume depletion can make the physical symptoms of jet lag worse, and that sleep on board can be maximised by minimising alcohol. Cabin air is dry: across 80 measured flights, average relative humidity at altitude was around 10 percent (National Academies, 2026). Why a drink breaks up the second half of the night is explained in alcohol and sleep.
Plan your caffeine. Caffeine helps with alertness during the day at your destination, and the CDC advises avoiding it in the hours before bed. A cup of coffee at the wrong local time will make the first night harder.
Does melatonin help with jet lag?
Yes, when it is taken at the right time. In the EU, this is one of the authorised claims for melatonin: "Melatonin contributes to the alleviation of subjective feelings of jet lag." The beneficial effect is obtained with a minimum intake of 0.5 mg taken close to bedtime on the first day of travel and on the following few days after arrival at the destination (Regulation (EU) No 432/2012).
The research behind that claim is consistent. A Cochrane review found ten trials that met its criteria, and eight of them found that melatonin taken close to the target bedtime at the destination, between 10pm and midnight, reduced jet lag. Daily doses between 0.5 and 5 mg were similarly effective (Herxheimer and Petrie, 2002). The CDC notes that 0.5 to 1 mg is often enough to produce a shift in the body clock and advises against high doses above 5 mg (Riedy and Williams, 2025).
Timing is the part people get wrong. "Bedtime" means the local bedtime where you are now, not the time your body thinks it is. Taken in the middle of the day, melatonin can make you sleepy and work against your adjustment to local time (Herxheimer and Petrie, 2002).
Where does Z-z-Zen fit into a trip?
On the first night of travel and the next few nights after you land. Each Z-z-Zen oral dissolvable strip contains saffron extract 14 mg, L-glycine 12 mg, L-theanine 12 mg and melatonin 1 mg. Take one strip 30 minutes before the local bedtime. Melatonin contributes to the reduction of time taken to fall asleep, and the beneficial effect is obtained by consuming 1 mg of melatonin close to bedtime (Regulation (EU) No 432/2012). Why the formula pairs melatonin with saffron, glycine and L-theanine is explained in inside the Z-z-Zen sleep formula.
The other two strips in the Travel Pack cover the hours around that night. FOCUS, with alpha-GPC 20 mg, caffeine 20 mg, L-theanine 10 mg, citicoline 10 mg and phosphatidylserine 5 mg, is for the meeting you land into. Its 20 mg of caffeine is a tenth of the 200 mg dose the CDC mentions for daytime alertness at a destination, so keep it to the morning and early afternoon. IMMUNE, with vitamin C 20 mg, elderberry juice concentrate 20 mg and vitamin D3 35 µg, keeps your daily habit going when travel breaks every other routine. Vitamin C contributes to the normal function of the immune system. Vitamin D contributes to the normal function of the immune system.
Why does a strip work well on the road?
On a plane or in a hotel room at midnight, the format decides whether you take anything at all. A Smart Strips oral dissolvable strip is an ultra-thin film that dissolves on the tongue in 7 to 30 seconds, with no water and nothing to swallow, and the sachets are light and compact enough to sit in a jacket pocket or a carry-on. Part of each dose is absorbed through the lining of the mouth, and for that part first-pass metabolism in the liver is significantly reduced. For the format, Smart Strips works with up to 95% bioavailability, up to 4x faster absorption and up to 30% higher effectiveness, delivered through a dissolving film made with QuickRelease™ (patent-pending) technology.
Every formula is sugar-free and gluten-free and sweetened with stevia, with 30 strips in a box. Smart Strips are made in the USA, in an FDA registered, cGMP certified facility. Practical tips for taking strips (or melts) in the air are in how to take supplements without water.
When should you talk to your doctor?
Talk to your doctor before you travel if you take regular medication, especially medicines that are timed to the clock, if you are pregnant or nursing, or if you have a medical condition. The CDC notes that there is limited data on how melatonin interacts with other medications. Do not take Z-z-Zen before you have to drive. If poor sleep continues long after you are home, that is worth raising with your doctor too.
Food supplements are not a substitute for a varied, balanced diet and a healthy lifestyle.
FAQ
How long does jet lag last?
It depends on the number of time zones and the direction. The body clock adapts by about 1 hour a day after flying east and about 1.5 hours a day after flying west (Riedy and Williams, 2025).
Why is jet lag worse flying east?
Flying east asks the body clock to move earlier, and for most people it is easier to delay the clock than to advance it.
When should I take melatonin for jet lag?
Close to the local bedtime at your destination, on the first day of travel and for the following few days after arrival. Avoid taking it during the day.
How much melatonin is in Z-z-Zen?
1 mg per strip, together with saffron extract, L-glycine and L-theanine. Take one strip 30 minutes before bed and follow the daily intake shown on the box.
Can I take the strips on a plane?
Yes. They are taken without water and dissolve on the tongue in 7 to 30 seconds. Keep the sachets in your carry-on so they are at hand when you need them.
What is in the Travel Pack?
Z-z-Zen, FOCUS and IMMUNE: one strip for the first nights in a new time zone, one for the working day after landing and one for the daily habit.
The first night in a new time zone sets the tone for the rest of the trip. Pack Z-z-Zen, or the full Travel Pack, for your next long flight.
Sources
- Riedy SM, Williams SG. Jet lag disorder. In: CDC Yellow Book: Health Information for International Travel. Centers for Disease Control and Prevention. 23 April 2025. https://www.cdc.gov/yellow-book/hcp/travel-air-sea/jet-lag-disorder.html
- Herxheimer A, Petrie KJ. Melatonin for the prevention and treatment of jet lag. Cochrane Database Syst Rev. 2002;(2):CD001520. DOI 10.1002/14651858.CD001520
- Commission Regulation (EU) No 432/2012 establishing a list of permitted health claims made on foods. Annex (melatonin, vitamin C, vitamin D). https://www.legislation.gov.uk/eur/2012/432/annex
- Blume C, Garbazza C, Spitschan M. Effects of light on human circadian rhythms, sleep and mood. Somnologie. 2019;23(3):147-156. DOI 10.1007/s11818-019-00215-x
- National Academies of Sciences, Engineering, and Medicine. Health and Safety Impacts of Aircraft Cabin Temperatures. 2026. Appendix B, Table B-1. https://www.nationalacademies.org/read/29472/chapter/10