What is melatonin?

Melatonin is a hormone produced by the pineal gland in your brain. It's carried in your blood to the rest of your body.

This hormone plays a role in managing your circadian (day and night) rhythm. Your melatonin levels are about 10 times higher at night than during the day. This helps control when you sleep.

Your melatonin levels are also seasonal. Levels of melatonin are higher in the autumn and winter when the nights are longer.

What is the role of melatonin?

Melatonin plays a role in your body's sleep and wake cycle.

Your melatonin levels increase about 2 hours before you go to sleep. This helps to get your body ready for sleep.

What happens if I have too little melatonin?

Too little melatonin can lead to sleep problems. In some studies, low levels of melatonin have also been seen in people with dementia.

Low levels of melatonin are also seen in people with:

• severe pain
• type 2 diabetes
• cancer
• some mood disorders

Your body's natural melatonin level tends to go down as you get older.

What happens if I have too much melatonin?

If you have too much melatonin, you are likely to:

• have a reduced body temperature
• become drowsy (sleepy)

You should not take melatonin before driving or operating machinery because it causes sleepiness.

How can I adjust my melatonin levels?

Exposure to light during the night can lower the amount of melatonin you make and release.

If you feel sleepy during the day, you should go out into the sunlight. This will help your body adjust your melatonin levels.

Blue light has been shown to reduce or delay the production of melatonin in the evening.

Electronic back-lit devices emit blue light, including:

• smartphones
• tablets
• readers
• computers
• fluorescent lights
• LED lights

Blue light can particularly make children vulnerable to sleep problems.

Good sleep hygiene

Good sleep hygiene can improve the quantity and quality of your sleep.

Try to do the following each day:

• go outdoors and expose yourself to sunlight
• get regular exercise
• don't smoke or vape
• avoid caffeine in the afternoon and evening

Developing good sleep habits is also very important. Try to:

• have a regular night routine
• take 30 minutes to wind down before bed and unplug from devices
• dim your lights
• only use your bed for sleep and sex

Learn more about sleep tips for children.

What are melatonin supplements used for?

Melatonin supplements can help reset your 'body clock' and sleep and wake at the right times.

This can help if you:

• have travelled overseas and have jet lag
• do shift work
• have age associated insomnia (problems sleeping)

Supplements can help you fall asleep at night and stay asleep for longer.

Melatonin is usually used for short-term sleep problems or to reset your body clock after shift work or jet lag.

If you have long-term sleep problems, see your doctor. There are other things you can do to help you sleep and further tests may be needed.

Very high levels of melatonin have an antioxidant effect. Antioxidants are thought to help stop the health issues caused by free radicals.

A form of melatonin is used to help treat depression.

When should I see my doctor?

See your doctor before you start taking melatonin. They will talk with you about your reasons for wanting to take melatonin. There are many reasons why you may have difficulty going to sleep or staying asleep.

They will also check that melatonin does not react with any other medicines that you take.

Your doctor will tell you how much melatonin to take and how often. It's normal to start with a low dose to see how your body responds. This also helps to lower your chance of having side effects.

If you're aged over 55 years, you can buy a slow-release form of melatonin over the counter. All other people need a prescription.

In Australia, melatonin can be used to treat insomnia in children with autism spectrum disorder, when other methods haven't worked.

Tips for taking melatonin

Taking melatonin doesn't work as well if you drink alcohol or smoke when using it.

Do not take other herbal remedies that encourage sleep at the same time as taking melatonin. This could make you very drowsy.

Don't use melatonin if you're pregnant, as its effect on your baby is not known.

Speak to your doctor about taking melatonin if you're breastfeeding.

Melatonin shouldn't be given to children under 2 years of age.

What are the possible side effects of taking melatonin?

Like all medicines, melatonin can cause side effects. Some of the side effects from taking too much melatonin as a supplement are:

• daytime sleepiness
• headaches
• nausea (feeling sick)
• dizziness
• in rare cases mood swings

While side effects in children are very rare, melatonin should only be used when suggested and prescribed by their healthcare professional.

Although melatonin is available online in various forms, it is strongly advised that children only use prescription-only formulations. The Therapeutic Goods Administration has issued a safety alert about concerns over imported melatonin.

We don't know much about the long-term use of melatonin in children.

Resources and support

• If you are having trouble sleeping, ask your pharmacist or doctor if taking melatonin is a good option for you.
• MindSpot's Sleep Course is a free, online program designed to help you improve your sleep.
• The Sleep Health Foundation provides information about insomnia and links to online resources and programs to assist you. They have information on sleep health and melatonin and sleep.
• The Health Resource Directory has advice on good sleep habits in Chinese, Arabic and Vietnamese.
• Visit the Australian Psychological Association for more information on getting help and treatment for insomnia.
• THIS WAY UP is a free online program which uses cognitive behavioural therapy (CBT) to help you deal with insomnia.

If your child is having trouble sleeping, call Pregnancy, Birth and Baby to speak to a maternal child health nurse on  1800 882 436 or video call. Available 7am to midnight (AET), 7 days a week.

You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with 24 hours a day, 7 days a week.