Melatonin for jet lag: direction, timing, amount
Futures Nutrition Editorial Team · 11 August 2026
Melatonin for jet lag: direction, timing, amount
11 August 2026
Jet lag has an authorised claim of its own, and its condition is more modest than most people expect: at least 0.5 mg, close to bedtime — on the first day of travel and on the first few days after arrival. No more than that. The figure that goes wrong in practice is therefore rarely the number of milligrams but the time of day: what is meant is bedtime at the destination, not the night on the plane and not the time back home. And one thing decides more than the tablet does, namely the direction of the flight — eastwards the adjustment is hard, westwards distinctly easier.
Melatonin contributes to the alleviation of subjective feelings of jet lag. The beneficial effect is obtained with the consumption of at least 0.5 mg of melatonin close to bedtime on the first day of travel and on the first few days after arrival at the destination.
Jet lag comes from time zones, not from hours in the air
The body runs an internal clock whose own period is slightly longer than 24 hours. It is reset daily — above all by light. A flight shifts external time within hours; the internal one only follows slowly. In between, the two do not match: you are tired in the afternoon, lie awake at night, and appetite and digestion still follow the old rhythm.
From this comes a distinction that saves a lot of trouble: long is not the same as jet lag. Frankfurt–Johannesburg takes around eleven hours and crosses a single time zone in summer — you are exhausted afterwards, but the internal clock is set correctly. Frankfurt–New York takes barely longer and shifts six hours. What counts is the number of time zones skipped; cramped seats, dry cabin air and a short night are travel fatigue and pass after one good sleep. Below about three time zones a plan is therefore not worth making; the evaluations behind the jet lag claim mostly concern flights across five or more time zones.
What the authorised claim says — and what it does not
Regulation (EU) No 432/2012 lists two claims for melatonin side by side. They are not interchangeable: each has its own amount and its own timing.
| Authorised claim | Amount per portion | Condition |
|---|---|---|
| Melatonin contributes to the reduction of time taken to fall asleep | 1 mg | close to bedtime |
| Melatonin contributes to the alleviation of subjective feelings of jet lag | at least 0.5 mg | close to bedtime on the first day of travel and on the first few days after arrival at the destination |
Two things are expressly not there. First, no upper limit of effectiveness — there is simply no second, stronger jet lag claim that would only apply from 5 or 10 mg upwards. Second, no number of days: "the first few days after arrival" stays open.
It is worth noting that the jet lag condition, at 0.5 mg, is lower than the 1 mg of the falling-asleep claim. The smallest strength on the market therefore meets it with a single tablet. Which strength belongs to which claim, and where medicines law begins, is set out in detail in Melatonin dosage: 0.5, 1, 2, 5 or 10 mg?.
East or west: direction decides more than amount
A flight west lengthens the day, a flight east shortens it. Because the internal clock runs a little slower than 24 hours by itself, lengthening comes easily and shortening does not — everyone knows this from the weekend when going to bed later is effortless and falling asleep earlier on Monday is not.
| Direction | What the body has to do | Usual speed of adjustment | Example from Frankfurt |
|---|---|---|---|
| westwards | lengthen the day, later to bed | roughly 1 to 1.5 hours per day | New York −6 hours |
| eastwards | shorten the day, earlier to bed | roughly 1 hour per day, often less | Tokyo +7 hours |
| north–south | nothing | no shift | Cape Town ±0 to 1 hour |
The figures are rough guides and vary considerably from person to person; the direction of the difference, on the other hand, is well documented. In practice this means: Tokyo needs closer to a week than three days, New York goes faster. The Cochrane review on melatonin and jet lag describes the same relationship — the benefit is greater the more time zones are crossed, and smaller on westward flights.
Timing follows the destination
This is where the most common mistake is made. It gets dark in the cabin, everyone puts on their eye mask, and the tablet goes down somewhere over the Atlantic. That is precisely not what the condition says. It says "close to bedtime" — and what is meant is the night just beginning at the destination. In the studies evaluated, melatonin was taken close to target bedtime, roughly between 10 p.m. and midnight local time.
This is not a formal distinction. Melatonin acts as a time signal, and a time signal at the wrong hour sets the clock in the wrong direction. The Cochrane review names exactly that as an occasional problem: taken too early, melatonin can delay adaptation instead of supporting it. Anyone who lands at 3 p.m. local time, yawns, and therefore takes a tablet straight away is shifting their internal clock further away from the destination.
A sequence for an eastward flight therefore looks like this:
| When | What |
|---|---|
| First day of travel | close to bedtime at the destination — even if that falls on the plane or right after landing |
| Nights 1 to 3 after arrival | each time close to going to bed by local time |
| During the day | no intake, not even with afternoon tiredness |
| Awake at night | nothing on top — the timing lies before going to sleep |
It helps in practice to set your watch to destination time when boarding and to plan everything by it from then on: meals, light, bedtime, tablet.
How many days — and when it is better not to adjust at all
"The first few days after arrival" is deliberately left open. In the studies, intake usually covered two to five days after landing. A usable stopping criterion is the evening itself: anyone who becomes tired at local time on their own and is awake at local time in the morning has the adjustment behind them.
Conversely, there are trips where adjusting is not worth it. On a short trip across two nights, the internal clock is almost back home before it would have arrived at the destination. It then makes more sense to stay in home time as far as possible — putting appointments into your own daytime window instead of adjusting twice.
Amount: the smallest strength meets the condition
The investigations into jet lag compared amounts between 0.5 and 5 mg. The result is sober: they affected the feeling of jet lag similarly; above 5 mg no additional benefit appeared. One side finding is interesting — a prolonged-release preparation performed comparatively poorly. That suggests a short, high peak suits the time signal better than a flat course across the night.
| Strength | Relation to the jet lag condition | Note |
|---|---|---|
| 0.5 mg | meets it with one tablet | in the studies similarly effective to 5 mg |
| 1 mg | meets it; at the same time the amount of the falling-asleep claim | one tablet for both claims |
| 2 mg divisible | half a tablet = 1 mg | one pack, two amounts |
| 5 and 10 mg | far above | no additional authorised claim |
For travelling, the smallest strength is therefore the one that fits precisely: melatonin 0.5 mg meets the condition of at least 0.5 mg with a single tablet and can be doubled to 1 mg if needed. Anyone who wants both amounts in one pack — 1 mg for home, less when travelling — is better served by the divisible melatonin 2 mg. The melatonin category gives an overview of all strengths.
Light is the stronger signal
The real timekeeper of the internal clock is light, and no tablet replaces it. The rule of thumb follows the direction of the flight: after an eastward flight, bright light in the morning helps to pull the rhythm forward — get outside as soon as it is light instead of sleeping in behind blackout curtains. After a westward flight it is the other way round: light in the evening keeps you awake until local time matches bedtime.
Part of this is also the opposite — avoiding light when it pulls the clock the wrong way. After a long eastward flight, the sun in the early morning of the first days is still deep night for the body; sunglasses on the way to the first appointment are then not an affectation but part of the plan. In the evening the reverse applies: dimmed light rather than ceiling lighting, screens put away early.
What else helps on the first day — and what does not
Alcohol on the plane. The drink above the clouds makes you sleepy and at the same time disturbs the course of the night; combined with melatonin it is no good idea anyway. Why is covered in Alcohol and melatonin.
Caffeine. On the day of arrival it is useful for holding out until local bedtime — but not in the late afternoon, or it shifts the very night that matters.
The afternoon nap. Short and early it is unproblematic. Two hours at 5 p.m. local time, on the other hand, take away the pressure the evening needs for the adjustment.
Meals. Eating is a weaker but measurable time cue — here too it pays to follow local time from the first day.
What melatonin on a trip is not meant for
The authorised claim relates to the subjective feeling of jet lag after a change of time zones — not to fear of flying, not to long night flights without a time shift, and not to catching up on sleep while sitting.
In its opinion No 42/2024, the German Federal Institute for Risk Assessment names as undesirable effects, among others, sleepiness the following day, headache, reduced attention and prolonged reaction times — including at amounts of 1 mg and below. On a trip this is particularly relevant: anyone picking up a hire car at the destination should plan the interval since intake. How long melatonin remains detectable in the body is set out in Melatonin duration: how long does it act in the body?. The same institute advises certain groups against taking it on their own initiative: children and adolescents, pregnant and breastfeeding women, people with impaired liver or kidney function or with epilepsy, and people taking blood pressure-lowering or anticoagulant medicines. Anyone taking medicines regularly is well advised to settle travel plans with a doctor beforehand — also because of possible interactions.
Food supplements are not a substitute for a balanced and varied diet and a healthy lifestyle.
The short version
- What counts are time zones, not hours in the air — below three, no plan is needed.
- The authorised claim requires at least 0.5 mg, on the first day of travel and the first days after arrival.
- The timing is bedtime at the destination, not the night on the plane.
- Eastwards the adjustment is harder and the benefit greater than westwards.
- Taken too early, melatonin shifts the internal clock in the wrong direction.
- Light is the stronger timekeeper: bright mornings after eastward flights, bright evenings after westward ones.
Frequently asked questions
Should I take melatonin while still on the plane?
Only if bedtime at the destination falls within the flight. The reference point of the condition is going to sleep at the destination — on an evening flight east that can indeed be above the clouds, on a daytime flight west it cannot. Setting your watch when boarding makes the decision easier.
How many milligrams do I need for ten time zones?
No more than for six. The condition states at least 0.5 mg, and in the investigations 0.5 to 5 mg affected the feeling of jet lag similarly, while above 5 mg no additional benefit was apparent. What grows with the number of time zones is the number of days until adjustment, not the number of milligrams.
Does it help on the flight home as well?
The condition does not distinguish between outward and return journey, only between the day of travel and the first days after arrival — on the way back, the destination is simply home. In practice the return westwards is usually the easier direction.
And if I forget to take it one evening?
Then it is not made up for, and certainly not doubled during the night. Back to local bedtime the next evening — the adjustment is not lost by it, it takes at most one day longer.
Matching products from our range
- Melatonin 0.5 mg – 365 tablets
- Melatonin 2 mg, divisible to 1 mg – 180 tablets
- View all melatonin products
Sources: Regulation (EU) No 432/2012 (authorised health claims, melatonin: jet lag at least 0.5 mg on the first day of travel and on the first days after arrival, falling asleep 1 mg close to bedtime); Herxheimer A, Petrie KJ, "Melatonin for the prevention and treatment of jet lag", Cochrane Database of Systematic Reviews 2002, CD001520 (intake close to target bedtime, 10 p.m. to midnight local time; flights across five or more time zones; 0.5–5 mg similarly effective, above 5 mg no additional benefit; prolonged-release preparation comparatively weak; smaller benefit on westward flights; intake that is too early can delay adaptation); CDC Yellow Book, chapter "Jet Lag Disorder" (light as the strongest time cue, recommendations by direction and number of time zones); German Federal Institute for Risk Assessment (BfR), opinion No 42/2024 on food supplements containing melatonin.
