What is melatonin?

Melatonin is a hormone produced by the pineal gland in the brain. Its level varies throughout the day and night to control your body clock.

Melatonin levels are higher at night and are lower in bright daylight. Your body naturally increases melatonin levels about 2 hours before going to sleep, to get you ready for sleep. You can take melatonin as a medicine to help with sleep problems, including insomnia, and for jet lag.

A form of melatonin has also been made as a medicine to help treat depression.

What is the role of melatonin?

Melatonin naturally helps control your body's sleep and wake cycles. It has also been claimed that melatonin has antioxidant effects that can prevent ageing and cancer, but claims aren't proven.

Taken as a medicine, melatonin can help reset the 'body clock' and help you sleep and wake at the right times. This can help if you have travelled overseas and have jet lag, if you do shift work, or if you have low vision. It can help you fall asleep at night and stay asleep for longer.

What happens if I have too little melatonin?

Too little melatonin can lead to sleep problems and in some studies low levels of melatonin have also been seen in people with dementia or Alzheimer's disease, severe pain, type 2 diabetes and some mood disorders.

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

What happens if I have too much melatonin?

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

Taking too much melatonin as a medicine or supplement may cause:

• headaches
• hypotension (low blood pressure)
• hypertension (high blood pressure)
• drowsiness
• vomiting
• alopecia (a health condition causing hair loss)

How can I adjust my melatonin levels?

If your melatonin levels are too high during the daytime and you feel sleepy (for example, if you have recently travelled a long distance and changed time zones), you should go out into the sunlight to help your body adjust your melatonin levels. Do some exercise in the daylight to help reset your body clock.

If you watch TV or use tablets, smartphones, laptops or other electronic devices before bed it can make it more difficult to fall asleep. The bright light from devices can stop your bodies from releasing melatonin. Playing games or interacting online also keeps you alert and can impact your ability to fall asleep afterwards.

Remember that getting a good night's sleep requires more than just taking melatonin. Developing good sleeping habits and a healthy lifestyle are very important. Avoid alcohol and cigarettes before bedtime.

You can adjust your melatonin levels naturally:

• Go outdoors in the daytime to expose yourself to natural sunlight.
• Get enough regular sleep.
• Eat regular meals.
• Avoid caffeine and nicotine.
• Avoid bright lights before bedtime.

Melatonin is available in Australia, but you do need to see your doctor for some prescription-strength formulations. Melatonin is now available over the counter for people aged over 55 years.

Don't take melatonin together with sedative or antidepressant medicines, or after drinking alcohol. Don't use melatonin if you are pregnant or breastfeeding.

When should I see my doctor?

Melatonin is usually used for short term sleep problems or to reset your body clock after shift work or jetlag. If you have long-term sleep problems, there are other things you can do to help you sleep and further medical investigations may be needed.

Melatonin may interact with other medicines such as antidepressants, so you should always discuss this with your doctor before you start taking melatonin or any new medication.

Before you give your child melatonin to help them sleep, check with a doctor or pharmacist. There are many reasons your child may have difficulty going to sleep or staying asleep that need to be considered. You should first try other methods to help your child sleep better before giving them melatonin.

Resources and support

If you are having trouble sleeping, ask your pharmacist or doctor if taking melatonin is a good option for you.

The Sleep Health Foundation provides advice on melatonin and sleep, as well as a downloadable fact sheet. They also offer ideas on sleep solutions and advise on the impact of technology and sleep.

Call healthdirect on 1800 022 222 (known as NURSE-ON-CALL in Victoria) for more information and advice. A registered nurse is available 24 hours a day, 7 days a week.

If your child is having trouble sleeping, call Pregnancy, Birth and Baby on 1800 882 436 for advice, support and guidance from our maternal child health nurses.