Melatonin 3mg Tablets
Use melatonin to treat the symptoms of jet lag, like fatigue and sleep disturbances.




Prices from £27.00
In stock. Simply fill in a brief questionnaire. One of our doctors will review your order and prescribe a suitable treatment. How to Order
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Melatonin tablets are a prescription-only treatment for jet lag. They contain a synthetic form of melatonin, a hormone naturally produced by the pineal gland in the brain that regulates your normal sleep/wake cycle. You’ll usually need to take one 3mg melatonin tablet every day for 5 days for effective treatment.
You can request melatonin tablets from Asda Online Doctor. If approved, your treatment can be delivered to your home address in discreet packaging or you can choose to collect it from your nearest Asda Pharmacy 4 hours after you have received a doctor’s approval.




About Melatonin
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Melatonin 3mg tablets are a prescription-only treatment for jet lag. They contain melatonin, a hormone that is naturally produced by your body to regulate your internal body clock or ‘circadian rhythm’.
If you travel quickly across 2 or more time zones, it can cause jet lag. Symptoms include:
- sleep disturbances
- irritability
- daytime tiredness
- fatigue
- digestive disturbances
- mental impairment
Melatonin tablets contain a synthetic version of melatonin that is prescribed to treat jet lag.
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Melatonin is a natural hormone that regulates the body’s biological day and night rhythm.
Usually, melatonin is produced by the brain and its levels rise during the night to help induce sleep. Melatonin levels peak during the early hours of the morning and fall during the day, controlling your natural sleep-wake cycle.
If you travel across time zones, your normal sleep-wake cycle can be disrupted, leading to sleep problems, also known as ‘jet lag’. By taking melatonin tablets, you’ll be adding to your body’s normal melatonin supply, restoring your body’s normal rhythm and reducing jet lag symptoms.
How long do melatonin tablets last?
Melatonin tablets have an average half life of 45 minutes. This is the time it takes for your body to get rid of half the medication.
You will usually be prescribed a 5-day course of melatonin tablets for jet lag.
How long do melatonin tablets take to work?
Melatonin tablets usually take around 1 to 2 hours to work.
How effective are melatonin tablets?
Clinical research has shown that melatonin tablets can reduce jet lag symptoms by 44% and shorten its duration. Two further studies found that melatonin effectively reduced jet lag duration by 33% when flying over 12 time zones.
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Swallow each melatonin tablet whole with water, milk, or fruit juice. You must not eat 2 hours before or 2 hours after you have taken a melatonin tablet.
Take your first dose of melatonin when you arrive at your destination at your normal bedtime, then take 1 melatonin tablet each day at your usual bed time until you have finished the course. It is important that you don’t take the tablet before 8pm or after 4am.
When to take melatonin tablets
You should take a melatonin tablet at your usual bedtime. For example, if you usually go to bed at 9pm, take a melatonin tablet at 9pm.
Melatonin tablet dosage
The usual recommended dose for adults is 1 tablet per day for a maximum of 5 days. If this is not effective, your doctor may advise you to increase your dose to 2 tablets.
Melatonin tablets can be taken for a maximum of 16 treatment periods per year.
How long do you need to take melatonin tablets for?
For jet lag, you will usually need to take melatonin tablets for 5 days.
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Melatonin tablets are a prescription-only medication for jet lag, they are not available over-the-counter. They might not be available on the NHS for jet lag, but you can obtain them from online doctor or pharmacy services with a private prescription in the UK.
Can I buy melatonin tablets online in the UK?
Yes, you can request melatonin for jet lag from Asda Online Doctor by:
- Completing a short online health assessment for one of our doctors to review.
- Placing your order.
- If approved, your order will be dispatched and sent to your home address in discreet packaging or you can choose to collect it from your local Asda Pharmacy 4 hours after a doctor’s approval.
- If your order isn’t approved, one of our doctors will contact you via your account with alternative treatment options.
Can I buy melatonin tablets over the counter?
No, melatonin is a prescription-only medication which means you must have a doctor’s approval before you can obtain it.
Do I need a prescription to buy melatonin tablets?
Yes, although in some countries melatonin can be bought online or in health shops as a complementary medicine, it is not available without a prescription in the UK.
Can I get melatonin tablets on the NHS?
Melatonin may be available on the NHS for certain sleep conditions, but it is unlikely to be available on the NHS for jet lag.
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Like all medications, melatonin tablets can cause side effects, but not everyone will experience them.
Common side effects include:
- drowsiness
- headache
Uncommon side effects include:
- dizziness
- high blood pressure
- abdominal pain
- indigestion
- mouth ulcers
- feeling sick (nausea)
- itching, rash, dry skin
- glucose in urine
- irritability, nervousness, abnormal dreams, anxiety, restlessness
- feeling unwell
- weight increase
Rare side effects include:
- high level of certain fats like triglycerides
- hot flushes
- watery eyes
- aggression
- mood changes
- nail disorder
- thirst
- being sick (vomiting)
- excess wind
- bad breath
- inflammation of the stomach lining
- pins and needles
- arthritis
- muscle spasms
- abnormal level of electrolytes in the blood
- prolonged erection that may be painful
- passing lots of urine
- restless leg syndrome
- memory problems
- increased sex drive
- inflammation of the prostate gland
How long do melatonin tablet side effects last?
Most melatonin side effects are mild and only last a short period of time because it does not stay in the body for long.
What to do if you get melatonin tablets side effects?
Most of the common or mild melatonin side effects can be managed at home.
Feeling sleepy
Avoid driving or operating tools or machinery if you feel sleepy or tired during the daytime. You should also avoid drinking alcohol as this can increase the effects. Because melatonin doesn’t last for long in the body, these effects will quickly wear off.
Headaches
If you experience headaches while taking melatonin tablets, get some rest, drink plenty of water, and take over-the-counter painkillers, if needed.
Feeling sick
Eat simple meals and avoid spicy or rich food. It can also help to eat and drink more slowly and have smaller, more frequent meals. If you are sick, drink plenty of water to keep you hydrated.
Dizziness
If you feel dizzy, stop what you are doing and sit or lie down until the sensation passes. Avoid driving or operating machinery if melatonin makes you feel dizzy.
Dry or itchy skin
Apply moisturiser to your skin often and if the symptoms do not improve after 1 week, speak to your doctor or pharmacist for advice.
If you experience any of the following serious side effects stop taking melatonin and get immediate medical help:
- chest pain
- vision changes including blurred vision
- fainting
- disorientation
- blood in your pee
- allergic reaction (swollen tongue or lining of the mouth)
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Melatonin tablets are an effective and safe treatment for jet lag, but like most medications, they aren’t suitable for everyone.
Do not take melatonin if you are:
- allergic to any of its ingredients
- under 18 years old
- pregnant or breastfeeding
Talk to your doctor before taking melatonin if you:
- have epilepsy as this can increase your risk of seizures
- have an autoimmune disease
- have diabetes or an impaired glucose intolerance
- have impaired liver or kidney function
- smoke
Melatonin with food and drink
You should avoid food for 2 hours before and 2 hours after taking melatonin.
It is also not recommended that you drink alcohol while taking melatonin because it can worsen jet lag symptoms.
Other medications and melatonin
Some medications can interact with each other. Before taking melatonin tablets, tell your doctor if you are taking or have recently taken:
- fluvoxamine
- psoralens
- cimetidine
- estrogens
- quinolones
- rifampicin
- carbamazepine
- benzodiazepines
- warfarin
You should tell your doctor if you are taking or plan to take any prescription, over-the-counter, or herbal medication while taking melatonin.
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Sleeping tablets or supplements may be useful if you are having difficulty sleeping, but these can be addictive and should only be used if your symptoms are severe.
Jet lag cannot be prevented, but there are some things you can do to treat jet lag when travelling.
During your flight
When flying or travelling to your destination, you should:
- drink plenty of water to stop you becoming dehydrated which can snake jet lag symptoms worse
- stay active by stretching and walking around the cabin which will signal to your body that it’s daytime
- try to sleep if it is night time at your destination to help your body get into a routine
- wear an eye mask and ear plugs as these can help you sleep if it is still light or the area is noisy
- avoid drinking alcohol or caffeine because these can act as stimulants and keep you awake
After you arrive at your destination
When you have arrived at your destination, you can manage jet lag by:
- changing your sleep schedule to the new time zone as soon as possible
- setting an alarm to avoid oversleeping in the morning
- getting outside during the day so that your body clock can adjust naturally
- not sleeping during the day as this can disrupt your normal sleep pattern at night
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Frequently asked questions
Are melatonin tablets the same as sleeping pills?
No, melatonin tablets are not the same as sleeping pills. Melatonin is a hormone that is naturally produced by the brain to regulate the sleep-wake cycle. Sleeping pills are medications that promote drowsiness leading to sleep.
Which doctors prescribe melatonin tablets?
Melatonin for jet lag is not available on the NHS prescription, so you will need a private prescription to obtain it, which some GPs may offer. You can also get melatonin for jet lag from a reputable online service such as Asda Online Doctor.
What is the difference between synthetic and natural melatonin tablets?
Natural melatonin tablets contain melatonin made by the pineal gland of animals. This type is not recommended because there is a risk it could be contaminated. Instead, synthetic melatonin tablets contain a man-made version that has been developed in a laboratory and is therefore tested, suitable, and safe to use.

Brenda studied medicine at St Georges University of London and has most recently worked in John Radcliffe Oxford University Hospitals, covering acute and general medicine.
Meet our doctorsLast reviewed: 26 Mar 2025
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About melatonin, NHS [accessed 12 February 2025]
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Common questions about melatonin, NHS [accessed 12 February 2025]
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Jet lag, NHS [accessed 12 February 2025]
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Melatonin 3 mg film-coated tablets, emc [accessed 12 February 2025]
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Side effects of melatonin, NHS [accessed 12 February 2025]


GMC: 7074021

GMC: 6149061

GMC: 7085115


Whether you’re going on holiday or returning home, jet lag can make it difficult to manage your energy levels. Asda Online Doctor by ZAVA offers melatonin treatment that can help you correct your body clock and reduce the effect jet lag has on your day-to-day activities.