Melatonin

Medication name

Melatonin ("MEL-a-TOE-nin")
Brand names

Circadin® ("SER-ka-din")

Slenyto (“SLEN–e-toe”)

Ceyesto (“SEE-es-to”)

Syncrodin (“SIN-cro-din”)

Adaflex (“ADD-a-flex”)
Medication type

Hormone

Tablets*: 1mg, 2mg, 3mg, 4mg and 5mg strengths

Liquid**: 1mg in 1ml

*Some melatonin tablets are modified-release, meaning the medicine is released into your body more slowly over a few hours.

**Also available as a sugar-free liquid.

There are other strengths and preparations available, including capsules, but they need to be ordered specially by the pharmacist.

If you have already tried techniques to improve your sleep and these have not worked, a doctor can prescribe melatonin for:

insomnia in children and adolescents (aged 6-17 years old) with ADHD
delayed sleep wake phase disorder (DSWPD) in children and adolescents aged 6-17 years and in adults up to 25 years of age
insomnia in children and adolescents aged 2-18 years with Autism and or Smith-Magenis syndrome

Your doctor will only consider prescribing melatonin if other things you have tried to help you sleep have not worked on their own. You should continue trying things to improve your sleep yourself even if melatonin is prescribed.

A specialist doctor may still consider this as a treatment option if you are 18 or older. This may be the continuation of existing treatment and if your own methods to help you sleep are not enough on their own.

Read our guide to sleep problems

About melatonin

Melatonin is a hormone that occurs naturally in the body. It helps regulate your body clock so you can sleep better. Unlike other medicines for sleep, melatonin works by signalling to your body that it is night-time and encourages your body’s own natural sleep-wake cycles to help you sleep better.

A ‘good night’s sleep’ and the amount of sleep people need can vary a lot. Different people need different amounts of sleep, and this can change with age.

Melatonin should be used alongside other ways of improving your sleep yourself.

When you are a teenager, your body clock shifts later, meaning you may find it hard to fall asleep at the same time as the rest of your family. If you are lying awake for hours, trying to fall asleep, try going to bed a bit later, until you are regularly falling asleep quickly. Don’t spend lots of time lying in bed when you’re not trying to sleep.
Make sure you get as much natural light as possible in the daytime, especially first thing in the morning. It can help to get some exercise as well.
Make your bedroom as dark, quiet, cool, and non-stimulating as possible.
Turn the brightness down on any screens in the evening and stop using your phone or tablet at least an hour before bed.
Charge your phone anywhere but in your bedroom.
Try to sleep and wake up at the same time every day (even at the weekends). Avoid regular, long lie-ins as they can make it harder to fall asleep at night.
Build a calm bedtime routine and use relaxation strategies to help you wind down.
If you can’t get to sleep, try not to give yourself a hard time about it. Get up, do something relaxing for a few minutes, and then try again.

These are just some of the things you can try. Different things work for everyone, and new routines can take time. Give these a go and see what works best for you.

Get more advice in our guide to sleep problems

Research has shown that in some conditions, the amount of melatonin the body produces naturally might be reduced, and the way that melatonin works to communicate between brain cells could be changed or altered.

We need to understand this better, but if you have tried ways to improve your sleep on your own and your sleep is still very disturbed, melatonin may help.

Melatonin will usually be started by a specialist doctor, and then continued by your GP if you find it works.

The aim of using melatonin is to establish a good sleeping pattern with the lowest effective dose.

Melatonin and everyday life

Melatonin starts to work about one to two hours after you take the dose. However, it can take a few days or weeks for you to benefit from the full effects. This is because it can take time to re-establish a normal sleep pattern as part of a healthy routine.

The effects of a dose of melatonin to support sleep can last for around four to eight hours after taking it.

A side effect of melatonin can be weight gain, but this is not common.

It is not possible to predict how melatonin will affect each person before they start taking it. Talk to your doctor or pharmacist if you are concerned about your weight, or changes to your weight, while taking melatonin.

You may want to let your family and friends know you are taking melatonin so they can support you and help you look out for side effects.

For guidance on this, check out our page on getting support with your medication.

Most people find melatonin will help improve their sleep, as this is what it is prescribed for.

In some people, there can be side effects that make their sleep worse, such as strange dreams/nightmares, and waking up early.

Even though melatonin is short acting, some people find that it is harder to wake up or that they feel very tired the following day.

If melatonin is not helping, or making your sleep worse, go back to your doctor to discuss trying something else.

Alcohol

Drinking alcohol while you are taking melatonin is not recommended as it means you might not get the maximum benefit from your medicine and might experience more side effects, such as headache, tiredness the following morning, or difficulty concentrating. This is very important if you need to drive, ride a bike, or operate machines.

Drinking alcohol every day, or in large amounts, can disrupt your sleep and make your symptoms worse. This can also mean you feel drowsy the next day.

Smoking

You may need to change your dose of melatonin if you stop or start smoking.

Chemicals in the smoke make your liver break down the melatonin more quickly.

If you smoke, you may need a higher dose of melatonin than someone who does not smoke.

Tell your doctor if you smoke before you start taking melatonin to make sure you get the right dose for you.

Go to your doctor for advice if you stop or start smoking, or if you switch to vaping or nicotine replacement products.

There is no effect from 'stop-smoking products' or e-cigarettes (vapes) on melatonin.

Get more advice on our drugs and alcohol guide.

Melatonin does not mix well with some other medicines, including herbal remedies. It may affect how they work or could cause more side effects.

Oestrogen can increase melatonin levels. If you start or stop taking a combined oral contraceptive or other form of hormone replacement therapy, discuss this with your doctor as your dose of melatonin might need to be adjusted.

Before you start taking melatonin, tell your doctor if you are taking any other medications including things you have bought from a pharmacy or other shop for common illnesses like colds and flu or medications that you put on your skin.

Always tell the pharmacist that you are taking melatonin if you buy any medicines from a pharmacy.

Look at the leaflet inside your medicine box for more information about other medicines that can interact with melatonin. With some medicines your doctor may need to adjust the dose of your medicines if you take them together. Ask a doctor or pharmacist for more information if you have any questions.

Avoid drinking too many caffeine drinks (coffee, cola or energy drinks) while you are taking melatonin, especially at bedtime.

Caffeine is a stimulant and therefore has the opposite effect of melatonin in your body, reducing its impact.

Caffeine can cause anxiety and sleep loss. Stopping these drinks might help to improve your symptoms.

There are several companies that manufacture this medicine and the non-active ingredients are likely to vary between products.

Always let your pharmacist know if you have any food allergies or intolerances, and always check with them if you’re concerned about any of the ingredients in your medication.

If you need to avoid animal products such as gelatine, please note that this is often found in capsules but also in some tablet formulations. Ask your pharmacist if you have any questions about the ingredients.

Further information about practical considerations for medicines if you need to avoid animal products can be found on the Vegan Society website.

Do not drive a car or ride a bike just after you start taking melatonin.

Taking melatonin may make you feel tired or dizzy or affect your eyesight when you start taking it. These are uncommon or rare side effects, but could affect you if you drive a car, ride a bike, or do anything else that needs a lot of focus.

It is recommended that you stop driving or riding a bike for the first few days until you know how it affects you.

Most people drive as normal while taking melatonin. If you are worried about this or have any concerns you would like to discuss, speak to your doctor or pharmacist.

Pregnancy

Melatonin is a naturally occurring hormone, but the medicine is a much higher dose than what is made in your body. There is very little information available about the effect of melatonin on a developing or newborn baby.

If you become pregnant while you are on melatonin, you should carry on taking your medicine and speak to your doctor about this as soon as possible. They can discuss the benefits and risks of continuing melatonin and help you make a decision that is best for you and your baby.

They may refer you to a specialist perinatal mental health team to support you with this decision. You can find out more information about taking melatonin during pregnancy at Bumps (Best Use of Medicines in Pregnancy).

Untreated illness can also be harmful to you and your developing baby, so decision about stopping or avoiding medication when you are pregnant need to be discussed carefully with your doctor. If you and your doctor agree that it is best for you to continue taking melatonin while pregnant, you should tell your midwife. If you are planning to get pregnant, it is recommended that you take folic acid while you are trying for a baby and during pregnancy. It is safe to take this together with melatonin.

Breastfeeding

Natural melatonin is passed to your baby in breastmilk. Melatonin as a medicine will also pass to your baby when breastfeeding but there is no evidence to say this is harmful.

If your baby was born early, then breastfeeding while taking melatonin may not be recommended. Talk to your midwife and doctor about feeding options.

If you breastfeed while taking melatonin, seek urgent medical advice if your baby becomes restless, very sleepy or develops feeding problems.

Sex

Melatonin can have side effects that may affect your sex life. These include:

low mood, which makes you feel less like having sex
hot flushes and excessive sweating in women
increased sex drive

A rare side effect of taking melatonin is a long-lasting and painful erection (called priapism). If this happens, you will need to be treated in hospital.

Untreated illness can have a negative effect on your sex life, so if melatonin helps you to recover, positive effects can include improving your desire, experience and enjoyment of sex as your mood lifts and you become interested in life and relationships again.

Fertility

There is no evidence to show that melatonin affects human fertility.

Melatonin is a naturally occurring hormone in the body, and alongside how to helps with sleep and regulating your body clock, there is ongoing research about how to supports other bodily functions, including during pregnancy and birth.

Melatonin is not a banned substance in sport.

Most people play sports as normal while taking melatonin. However, it can make you feel sleepier so may affect your ability to play sports that need a lot of focus. It might be best to stop these sports for the first few days until you know how it affects you or the effects get better. If you have any concerns, discuss this with your doctor.

Ideally, try not to not to take melatonin for the first time just before your exams, as it may affect your concentration.

It’s not possible to predict how the medication will make you feel, and if you do get any side effects, these are more likely to occur when you first start taking melatonin.

You should talk to your doctor about any future exams if you are starting melatonin. You might decide together to delay starting it until you have done them.

If they are more than a month away, however, you might find that it is better to start melatonin to improve your sleep, motivation and ability to study.

Most people take exams as normal while taking melatonin, but if you have any concerns, discuss this with your doctor.

Information and safety considerations

Your doctor will consider any other medical conditions or symptoms you have before recommending a medicine for you.

Your medicine will come with a ‘patient information leaflet’. It’s important that you read this information. Speak to your pharmacist if:

you’re not given a leaflet
you don’t understand the information
you need it in a different format or language
you’re concerned about something you’ve read

The information leaflet also includes a list of warnings and precautions to consider before you take the medicine. If you think that any of these apply to you and are concerned that your doctor is not already aware of them, check with your doctor or pharmacist before you start to take your medication (or as soon as possible if you are already taking it).

Uses, warnings, safety and side effects

Taking melatonin

Your doctor may recommend that you take melatonin for up to three months to assess how it helps you. This will support you to re-establish a normal sleep pattern as part of a healthy routine.

If you find melatonin is helpful for you, your doctor will talk to you about whether to continue taking it. Some people take it for several years or longer.

If you continue to take melatonin, your doctor will review this with you at least once every six months.

Having a treatment break to find out how you get on without melatonin is helpful when considering if treatment should be continued or not. Your doctor will also discuss other things you can do to help improve your sleep if you are still finding this difficult.

You may take melatonin every day, or you might have regular days every week where you don’t take it. For some people, not taking it every day can help melatonin work more effectively for longer.

You will get the best effect from melatonin if you take it at the dose prescribed by your doctor.

Take melatonin 30 minutes to one hour before you go to sleep.

If you are prescribed modified release or slow-release tablets, it is important to swallow these whole with or after food, even if this is just a small snack. Do not break or chew the modified-release tablets. This is because they have a special system in them to deliver the medicine into your body slowly, over a few hours. Swallow the tablet whole with at least half a glass of water while sitting or standing.

Some tablets can be crushed if needed if that makes it easier for you to take them. If you have to crush the tablets to help you take them, talk to your doctor who can change your medication to an immediate release tablet instead.

If you are prescribed immediate release tablets, capsules or liquid melatonin, it is recommended that you don’t eat for two hours before or after taking these. Depending on your bedtime, this could be difficult for you, and going to bed hungry can also affect your sleep. Try and have your main evening meal at least two hours before you take your dose but having supper or a small snack later in the evening, within two hours of taking melatonin, will not affect the safety of your medicine or stop it working.

If you remember before you go to sleep, take it as soon as possible.

If you forget completely, skip the dose and start taking it again the following evening. Do not try and catch up by taking a double dose the following night.

For immediate release melatonin, if you forget to take melatonin at bedtime, you could take the dose if you wake during the night. But if this is after one o’clock in the morning, it is recommended that you skip the dose and start again the following evening.

It is important to follow the information your doctor or sleep specialist has given you about times after which you shouldn’t take melatonin.

If you forget to take your tablets for a few days, it is possible you may not sleep so well on these nights. However, some people do not take melatonin every night, and this is still enough to help improve their sleep pattern.

If you forget to take doses, keep a diary of how you slept. This will help when you next review your medication with your doctor.

You do not get discontinuation or withdrawal symptoms if you forget to take melatonin.

You should not get any harmful discontinuation or withdrawal effects if you stop taking melatonin. However, if melatonin is beneficial for you, it is possible you might not sleep so well.

If you are on a high dose, then the doctor may wish to reduce the dose slowly before stopping it completely, but this is not necessary.

Your doctor will review your prescription for melatonin with you at least every six months. It is likely your doctor will ask you to complete sleep diaries to help with this. A short treatment break will also help understand if the melatonin is still making a difference for you and whether it might be beneficial to continue or not.

Warnings and safety

If you have taken more than the dose prescribed by your doctor, contact NHS 111 immediately to ask for advice, or ask a family member or friend to do this for you. This is important even if you don’t feel any different.

NHS 111 can give you advice and direct you to the best place to get more help if you need it.

If you have taken too much medication on purpose, or if after taking this you quickly feel unwell, call 999 or get someone to take you to A&E straight away.

If you need to go to A&E, do not travel alone or drive yourself there. Get your parent, family member or friend to go with you to support you and keep you safe on the way. If someone is not able to drive you there, call for an ambulance. Take your medication with you and tell doctors how much you have taken.

Serious side effects

Rarely, melatonin can cause serious side effects, including allergic reactions.

Stop taking pregabalin and go to a hospital straight away if you get any of the following symptoms:

breathing difficulties
swelling of the lips, mouth, tongue, throat, hands or feet
severe faintness or dizziness

Contact your doctor immediately but don't stop taking melatonin, if you get any of the following symptoms:

fainting or losing consciousness
dizziness or vertigo (which may feel like ‘spinning’)
feeling mixed up and confused (disorientated)
severe chest pain or changes in heartbeat
depression (feeling low)
problems with your eyesight
blood in your wee
unusual bleeding or bruising
a flaky pink/red rash on your skin, particularly on your elbows and knees (psoriasis)

If you are unable to contact your doctor, call NHS 111 for urgent advice.

Side effects and your health

Side effects are more common when you first start taking a new medicine. Many go away as you continue your medicine. If they don’t get better, or if you are worried by them and they are causing you distress, speak to your doctor, specialist team or pharmacist about them.

Common side effects (affecting up to one in 10) people include:

drowsiness and tiredness (which may continue the following morning or day)
headaches – speak to your pharmacist about pain relief (like paracetamol) if you experience this
changes in mood, feeling irritable or agitated
occasional muscle pain

There are other side effects that you can get when taking this medicine. We have only included the most common ones here.

This list of side effects can look scary. You may not experience any of them, but it’s important to be aware of them so you know what to do if they do happen.

Unless your side effects are very severe or distressing, try to continue taking your medication until you can talk to your doctor. Your doctor can make changes to your medication to help if needed.

There is no additional monitoring routinely recommended with melatonin.

Your doctor may recommend additional checks depending on any other medical conditions you have or if you get any side effects from your medicine. A blood test may be needed for this.