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Melatonin - for sleep problems

On this page

  1. About melatonin
  2. Key facts
  3. Who can and cannot take melatonin
  4. How and when to take it
  5. Side effects
  6. How to cope with side effects
  7. Pregnancy and breastfeeding
  8. Cautions with other medicines
  9. Common questions

1. About melatonin

Melatonin is a hormone that occurs naturally in your body. It helps control your sleep patterns.

You can take a manmade version of melatonin for short-term sleep problems (insomnia). It makes you fall asleep quicker and less likely to wake up during the night. It can also help with symptoms of jetlag.

Melatonin is used to treat sleep problems in people aged 55 and over.

It can sometimes be prescribed to help with sleep problems in children and to prevent headaches in adults.

Melatonin is available on prescription only. It comes as slow-release tablets and a liquid that you drink.

2. Key facts

  • Melatonin is mainly used to treat sleep problems in adults aged 55 or older.
  • You'll usually take it for 1 to 4 weeks.
  • Some people may get a headache after taking melatonin, or feel tired, sick or irritable the next day.
  • Avoid drinking alcohol or smoking while taking melatonin. These stop the medicine working as well as it should.
  • Melatonin is also known by the brand name Circadin.

3. Who can and cannot take melatonin

Melatonin is mainly prescribed for adults aged 55 or over, to help for short-term sleep problems.

It can sometimes be used by adults under the age of 55 and by children, if a doctor recommends it.

It's not suitable for some people. To make sure melatonin is safe for you, tell your doctor if you:

4. How and when to take it

The dose will vary depending on why you're taking it. Follow the instructions that come with your medicine if you're taking melatonin to:

  • prevent headaches
  • treat jet lag

If your child is prescribed melatonin, follow the doctor's instructions carefully. Find out more about giving melatonin to children from Medicines for Children.

For sleep problems in adults

Your doctor will prescribe 2mg slow-release (or prolonged-release) tablets. These release melatonin gradually into your body during the night.

It's important to follow the instructions carefully. Your doctor may tell you to take melatonin only 2 or 3 times a week, and not every night.

You'll usually take melatonin for just a few weeks to help with short-term sleep problems (insomnia). However, it is sometimes prescribed for up to 13 weeks.

How to take it

For sleep problems in adults, the usual dose is one 2mg tablet. Take the tablet 1 to 2 hours before bedtime. This is because the medicine takes a couple of hours to start working.

Take melatonin after food.

Swallow the tablet whole. Do not crush or chew it.

What if I forget to take it?

If you forget to take melatonin by bedtime, skip the missed dose and start again the next night.

Never take 2 doses at the same time. Never take an extra dose to make up for a forgotten one.

What if I take too much?

If you take 1 or 2 extra tablets of melatonin by accident, it's unlikely to harm you.

Urgent advice: Get advice from 111 now if:

  • you've taken too much melatonin and feel unwell

Go to or call 111.

If you need to go to hospital, take the melatonin packet or leaflet inside it, plus any remaining medicine, with you.

Ask someone to go with you to hospital as you may start to feel very sleepy on the way. If you're travelling by car, do not drive yourself.

5. Side effects

Most people will not have any side effects when taking melatonin.

Common side effects

These common side effects happen in more than 1 in 100 people.

Talk to your doctor or pharmacist if these side effects bother you or do not go away:

  • feeling sleepy or tired in the daytime
  • headache
  • stomach ache or feeling sick (nausea)
  • feeling dizzy
  • feeling irritable or restless
  • dry mouth
  • dry or itchy skin
  • pains in your arms or legs
  • strange dreams or night sweats

Serious side effects

Serious side effects are rare and happen to less than 1 in 1,000 people.

Speak to a doctor as soon as possible if you:

  • start feeling low or sad – this could be a sign of depression
  • get blurry vision or your eyes become more watery than usual
  • feel faint or pass out
  • start feeling confused or dizzy, or things seem to be spinning around you (vertigo)
  • have any bleeding that does not stop, unexplained bruising or blood in your urine
  • get psoriasis

Immediate action required: Call 999 or go to A&E now if:

Serious allergic reaction

In rare cases, it's possible to have a serious allergic reaction (anaphylaxis) to melatonin.

Immediate action required: Call 999 or go to A&E now if:

  • you get a skin rash that may include itchy, red, swollen, blistered or peeling skin
  • you're wheezing
  • you get tightness in the chest or throat
  • you have trouble breathing or talking
  • your mouth, face, lips, tongue or throat start swelling

You could be having a serious allergic reaction and may need immediate treatment in hospital.


These are not all the side effects of melatonin. For a full list, see the leaflet inside your medicine packet.

You can report any suspected side effect to the UK safety scheme.

6. How to cope with side effects

What to do about:

  • feeling sleepy or tired in the daytime – do not drive, cycle or use tools or machinery if you're feeling this way. Do not drink any alcohol as this will make you feel more tired. If this does not help, talk to your doctor as melatonin may not be the right medicine for you.
  • headache – make sure you rest and drink plenty of fluids. Do not drink too much alcohol. Ask a pharmacist to recommend a painkiller. Talk to a doctor if headaches last longer than a week or are severe.
  • stomach ache or feeling sick (nausea) – take your medicine after food. It can help to eat and drink slowly and have smaller and more frequent meals. Putting a heat pad or covered hot water bottle on your tummy may also help ease any pain.
  • feeling dizzy – if taking melatonin makes you feel dizzy, stop what you're doing and sit or lie down until you feel better. Do not drive, cycle or use tools or machinery if you're feeling dizzy. Do not drink alcohol as it will make you feel worse.
  • feeling irritable or restless – if this does not get better after a few days, stop taking the medicine and talk to your doctor.
  • dry mouth – chew sugar-free gum or suck sugar-free sweets.
  • dry or itchy skin – apply a moisturiser often. Try using an oil-free face moisturiser for sensitive skin.
  • pains in your arms or legs – if this does not get better after a few days, stop taking the medicine and talk to your doctor.
  • strange dreams or night sweats – if this does not get better after a few days, stop taking the medicine and talk to your doctor.

7. Pregnancy and breastfeeding

It's best to avoid taking melatonin if you're pregnant or if you want to breastfeed. Not enough research has been done to know whether it's safe for you and your baby.

Melatonin passes into breast milk in small amounts and this can make a baby more sleepy. If you want to breastfeed, talk to a doctor or midwife first before taking melatonin.

Non-urgent advice: Tell a doctor if you're:

  • trying to get pregnant
  • pregnant
  • breastfeeding

8. Cautions with other medicines

Some medicines and melatonin can interfere with each other and increase your risk of side effects.

Certain medicines may increase or decrease the drowsy-making (sedating) effects of melatonin.

Speak to a doctor or pharmacist before taking melatonin if you take any of the following:

  • antidepressants such as fluvoxamine or imipramine
  • blood pressure lowering medicines
  • nonsteroidal anti-inflammatory medicines (NSAIDs) such as ibuprofen, naproxen or diclofenac
  • oestrogens (used in contraceptives and hormone replacement therapy)
  • opiate agonists or antagonists (for drug addiction)
  • psoralens (for skin disorders such psoriasis)
  • quinolones or rifampicin (types of antibiotic)
  • carbamazepine (for epilepsy)
  • cimetidine (for stomach problems such as ulcers)
  • thioridazine (for schizophrenia)
  • tryptophan supplements (for insomnia)
  • warfarin (a blood thinner)
  • zaleplon, zolpidem or zopiclone (for insomnia)

Mixing melatonin with herbal remedies and supplements

Do not take any herbal remedies that make you feel sleepy while taking melatonin.

They can increase the sedating effects of your medicine and make you feel much more drowsy.


Tell a doctor or pharmacist if you're taking any other medicines, including herbal remedies, vitamins or supplements.

9. Common questions

How does melatonin work?

Melatonin is a natural hormone that is produced by the pineal gland (located in your brain). It helps control your sleep cycle.

The body produces melatonin just after it gets dark, peaking in the early hours of the morning and reducing during daylight hours. Melatonin acts on receptors in your body to encourage sleep.

Taking melatonin tablets adds to your body's natural supply of the hormone. This can help you get to sleep and improve the quality of your sleep.

How long will it take to work?

Melatonin takes around 1 to 2 hours to work.

How long will I take it for to treat insomnia?

You'll usually be prescribed melatonin for 1 to 4 weeks.

In some cases it can be prescribed for up to 13 weeks.

If you still have sleeping problems after finishing your course of melatonin, try making lifestyle changes that can help with insomnia.

See a doctor again if these tips do not help.

How does melatonin work for jet lag?

Melatonin has been approved as a short-term treatment for jet lag in adults.

There is some evidence that melatonin makes your symptoms less severe. It can also help reduce recovery time after a long flight by a day to a day and a half.

Jet lag can be common after travelling across 5 or more time zones in an easterly direction. It disturbs your sleep, your thinking and your digestion, and can make you feel irritable and tired during the daytime.

The usual dose is one 3mg tablet of melatonin but your doctor may recommend 2 tablets (6mg) if needed.

When you arrive at your destination, take melatonin at your normal bedtime (but not earlier than 10.00pm and not later than 4.00am).

You can use melatonin for up to 5 nights in a row.

Melatonin for jet lag may not be available for you on NHS prescription.

Will I sleepwalk with melatonin?

Taking melatonin has not been linked to sleepwalking.

If this happens to you, go back to a doctor for advice.

Can I get addicted to melatonin?

Melatonin is usually only recommended for short-term sleep problems. If you take it as prescribed, you're unlikely to become addicted to it.

However, ask a doctor or pharmacist for advice about stopping melatonin if you have been taking it for a long time or if you're worried about becoming dependent on it.

They can help you come off your medicine gradually.

Can I drive or ride a bike?

Do not drive a car, ride a bike or operate machinery if melatonin makes you sleepy, gives you blurred vision, or makes you feel dizzy, clumsy or unable to concentrate or make decisions.

This may be more likely when you first start taking melatonin, but could happen at any time. For example, when starting another medicine.

It's an offence to drive a car if your ability to drive safely is affected. It's your responsibility to decide if it's safe to drive. If you're in any doubt, do not drive.

GOV.UK has more information on the law on drugs and driving.

Talk to a doctor or pharmacist if you're unsure whether it's safe for you to drive while taking melatonin.

Will it affect my fertility?

There's no firm evidence to suggest that taking melatonin will reduce fertility in either men or women.

But speak to a pharmacist or doctor if you're trying to get pregnant. They may want to review your treatment.

Will it affect my contraception or HRT?

Melatonin does not affect how contraception works, including the combined pill and emergency contraception.

However, your levels of melatonin can increase when taking the combined pill or hormone replacement therapy (HRT).

Speak to a doctor or pharmacist before taking melatonin if this applies to you.

Is there any food or drink I need to avoid?

Do not have drinks that contain caffeine (including coffee, cola or energy drinks) while you're taking melatonin.

Caffeine has the opposite effect of melatonin and stops it working.

Can I drink alcohol with it?

No. Do not drink alcohol while you're taking melatonin.

Alcohol and melatonin together can make you sleep very deeply, so you do not breathe properly and can have difficulty waking up.

Can I buy melatonin supplements at a health food shop?

In some countries, melatonin is available to buy in health food shops or online. It is sold as a complementary medicine and comes as "immediate-release" capsules, tablets or a liquid that your drink.

However, these supplements are not authorised for sale in the UK. Melatonin is a prescription-only medicine in the UK.

Ordering melatonin online is not recommended. Find out more about the dangers of buying medicines online.

Will recreational drugs affect it?

Using cannabis, heroin or methadone with melatonin will increase the medicine's sleep-inducing effects. You could go into a very deep sleep and have difficulty waking up.

Talk to a doctor if you think you might use recreational drugs while you're taking melatonin.

Can lifestyle changes help with insomnia?

There are a number of things you can do to help yourself beat insomnia, such as:

  • set regular times for going to bed and waking up
  • relax before bedtime – try taking a warm bath or listening to calming music
  • use thick curtains or blinds, an eye mask and earplugs to stop you being woken up by light and noise
  • avoid caffeine, cigarettes (including e-cigarettes), alcohol, heavy meals and exercise for a few hours before going to bed
  • do not watch TV or use phones, tablets or computers just before going to bed
  • do not nap during the day
  • write a list of your worries, and any ideas about how to solve them, before you go to bed to help you forget about them until the morning

Some people find sleeping tablets you can buy in a pharmacy helpful. But these do not cure insomnia and can have unwanted side effects.


Do not take any medicines or herbal remedies that make you feel sleepy while taking melatonin.

They can increase the drowsy-making (sedating) effects of your medicine.