Jet lag — how to reduce it
Reviewed by the My London Pharmacy clinical team, Yvonne Lim, Pharmacist Independent Prescriber
·29 July 2026
·7 min read
Quick answer
Jet lag happens when your body clock is out of step with a new time zone, usually after flying across three or more. It settles on its own, but adjusting your sleep, light exposure and meal times towards your destination, and in some cases short-term melatonin, can help you feel better sooner.
What jet lag is and why it happens
Jet lag is a temporary sleep problem that follows rapid travel across several time zones. Your internal body clock, or circadian rhythm, keeps you roughly in tune with day and night at home, quietly influencing when you feel alert, when you feel sleepy, your body temperature, digestion and the release of certain hormones. When you land somewhere several hours ahead or behind, that clock is still running on your original time while the world around you follows a different schedule.
The result is a mismatch between your internal timing and the local day. Your body still expects to sleep, eat and wake at home-time, so you can feel wide awake in the middle of the night and heavy with tiredness during the day. Crossing three or more time zones is usually where symptoms become noticeable, and the more zones you cross, the more pronounced they tend to be. Jet lag is a normal response to travel rather than an illness, and it eases as your body clock gradually resets to the new time zone.
Common symptoms to expect
Jet lag affects people differently, and factors such as age, general health and how well you sleep at the best of times can all play a part. Most travellers, though, notice a familiar cluster of symptoms in the first few days after arrival. These can include:
- Difficulty falling asleep, staying asleep, or waking too early
- Daytime tiredness, low energy and an urge to nap at odd times
- Poor concentration or feeling mentally foggy and slow
- Changes in appetite, mild indigestion or an unsettled stomach
- Headaches, low mood, and a general sense of being unwell or irritable
Symptoms usually improve gradually, often at a rate of about one time zone per day, though this varies from person to person. Many people find the first two or three days the hardest before things begin to settle. If tiredness or low mood lingers well beyond your trip, or if you feel unwell in other ways, it is worth speaking to a clinician to rule out other causes rather than assuming jet lag is to blame.
Why the direction of travel matters
Travelling east tends to be harder than travelling west. Flying east shortens your day and asks your body clock to move earlier, which most people find more difficult than staying up later. Heading west lengthens your day, and delaying sleep usually feels more natural, which is why many travellers cope better on westward journeys.
Knowing which way you are going helps you plan. For eastward trips, gradually shifting your bedtime and wake time earlier in the days before you fly can soften the adjustment. For westward trips, staying up a little later in advance may help instead. Even a partial shift of an hour or two before departure can reduce how out of step you feel on arrival. Very long journeys that cross many time zones may take longer to recover from, and it can help to build a rest day into your plans where possible.
Preparing in the days before you fly
Some of the most useful steps happen before you even reach the airport. In the two or three days ahead of travel, try gradually nudging your daily routine towards your destination's time. Shift your bedtime, wake time and meals slightly earlier for eastward trips, or slightly later for westward ones, so your body clock has a head start.
It also helps to travel well rested. Arriving already short on sleep tends to make jet lag feel worse, so try to avoid the common temptation to stay up late packing or working the night before. Going into a trip with your energy topped up gives your body more to draw on while it adjusts. Planning the timing of your arrival can help too: landing in the evening, when you can head to bed reasonably soon, is often easier to manage than arriving first thing in the morning with a full day ahead.
Practical steps to adjust faster
Simple habits around light, sleep and routine make the biggest difference to how quickly you settle. Once you arrive, move your daily schedule to local time as soon as you can, including meals and bedtime, and resist the urge to check what time it is back home.
- Use daylight deliberately. Natural light is the strongest signal for your body clock. Morning light generally helps after eastward travel, while evening light can help after westward travel, encouraging your rhythm to shift in the right direction.
- Set your watch to the destination as you board, and start thinking and behaving in local time straight away.
- Stay hydrated and go easy on alcohol and caffeine, particularly in the hours close to bedtime, as both can disrupt sleep and leave you feeling worse.
- Take short naps if needed, but keep them to around twenty to thirty minutes so they do not interfere with night-time sleep.
- Keep your sleep environment dark, quiet and cool, and use an eye mask or earplugs if your surroundings are unfamiliar.
- Stay active during daylight, as gentle activity and being outdoors help reinforce the local day and lift daytime alertness.
For short trips of only a day or two, some travellers choose to stay on home time rather than fully adjust, which can be easier than shifting the clock twice in quick succession.
When melatonin may be considered
Melatonin is a hormone your body naturally releases in the evening to signal that it is time to sleep. As a short-term option, a melatonin preparation is sometimes used to help realign the body clock after crossing several time zones, and NICE recognises it as one approach for jet lag in appropriate cases.
Products such as Ceyesto (melatonin 3mg) and Circadin (Melatonin) 2mg Tablets are prescription treatments in the UK, so they are only suitable after a clinician has reviewed your circumstances, travel plans and any other medicines you take. Timing is important, as taking melatonin at the wrong point can be unhelpful or even work against the shift you are trying to achieve, and it is not right for everyone. It may not be suitable for certain health conditions, in pregnancy, or alongside some medicines, which is why a personalised assessment matters. A clinician can advise whether it may be suitable for you and how to use it correctly.
Melatonin works best alongside the light, sleep and routine measures above rather than in place of them. It is intended as short-term support around travel, not an ongoing sleep aid, and combining it with good habits tends to give the best chance of settling quickly.
When to seek advice
Jet lag is self-limiting and rarely a cause for concern. However, it is worth speaking to a pharmacist or clinician if your symptoms are severe, if you have a health condition such as diabetes or epilepsy where changing your routine and medication timing needs care, or if you take regular medicines that must be taken at set times. Crossing time zones can complicate dosing schedules, and a little planning can prevent problems.
It is also sensible to seek advice if disrupted sleep continues long after you would expect to have adjusted, or if low mood, persistent fatigue or other symptoms make you wonder whether something else is going on. If you travel frequently or have an important trip ahead, a short conversation with the My London Pharmacy team can help you put a personalised plan in place and discuss whether any treatment is appropriate for you.
Frequently asked questions
How long does jet lag usually last?
Most people adjust at a rate of roughly one time zone per day, so a five-hour time difference may take around five days to settle. Planning your light exposure and sleep can help you feel better sooner.
Is jet lag worse flying east or west?
Travelling east is generally harder because it asks your body clock to move earlier, which most people find more difficult than delaying sleep when flying west.
Can I prevent jet lag before I fly?
You cannot always prevent it, but gradually shifting your sleep and wake times towards your destination in the days before travel, and arriving well rested, can reduce how out of step you feel.
Is melatonin available without a prescription for jet lag?
In the UK, melatonin is a prescription-only medicine. A clinician needs to review your circumstances before it can be supplied, so speak to the pharmacy team about whether it may be suitable.
Do naps help or make jet lag worse?
Short naps of around twenty to thirty minutes can ease daytime tiredness, but long or late naps may make it harder to sleep at night. Keeping any nap brief helps you adjust to local time.
Does drinking alcohol on the plane make jet lag worse?
Alcohol can disrupt sleep quality and add to dehydration, which may leave you feeling worse on arrival. Drinking water and limiting alcohol and caffeine tends to help you settle.