Sounds like 'mel-a-to-nin'

Easy-to-read medicine information about melatonin – what it is, how to take melatonin safely and possible side effects.

Type of medicine Also called
  • Medicine to improve sleep (hypnotic)
  • Circadin®
  • Melatonin (Twinlab)®
  • Country Life®

What is melatonin?

  • Melatonin is a hormone produced by a gland in our bodies known as the pineal gland. It helps to control the body's sleep pattern and sleep-wake cycle.
  • A slow release tablet that releases melatonin slowly over a few hours is available on prescription in New Zealand. It can be prescribed:
    • to help with sleep problems in the people over 55 years.
    • for children and young people up to the age of 18 years who have neurodevelopment disorders that make it difficult to sleep.
  • Melatonin may also help prevent or reduce jet lag if flying across 5 or more time zones, but it is not approved for this use in New Zealand. 

 How to take melatonin

  • Take your melatonin dose 1 or 2 hours before bedtime, with a snack.
  • Swallow melatonin slow-release tablets (Circadin®) whole. Do not chew because this will release all the medication at once.
  • If you cannot swallow tablets, the slow-release tablets can be crushed and mixed with a drink. This means the tablets would no longer be slow-release and should be taken just before bedtime.
  • Limit or avoid alcohol, while taking melatonin because alcohol can affect how it works. 
  • It is not harmful if you miss your melatonin dose. If you forget to take your dose at the usual time, but you remember before you go to sleep, take it when you remember.
  • But, if you do not remember until the following day, just take the next dose at the right time. Do not take double the dose.
  • Do not take melatonin for longer than your doctor advises. It can be prescribed for up to 13 weeks.

Precautions – before taking melatonin

Is your answer 'yes' to any of the following questions?

  • Do you have an autoimmune disease (a condition in which the body is attacked by its own overactive immune system) such as rheumatoid arthritis, multiple sclerosis or lupus?
  • Do you have problems with the way your kidney or liver works?
  • Do you have epilepsy, high blood pressure, or diabetes?
  • Do you have depression?
  • Are you pregnant or planning a pregnancy?
  • Are you breastfeeding?

If so, it’s important that you tell your doctor before you start melatonin. Sometimes a medicine isn’t suitable for a person with certain conditions, or it can only be used with extra care.

Possible side effects

Like all medicines, melatonin can cause side effects, although not everyone gets them. Often side effects improve as your body adjusts to the new medicine.

Side effects What should I do?
  • Feeling tired or sleepy
  • Drowsiness
  • Be careful when driving or using tools until you know how this medicine affects you.
  • Indigestion
  • Stomach upset
  • Nausea (feeling sick)
  • Try taking melatonin with food or a snack
  • Muscle, bone or joint pains 

  • Tell your doctor if troublesome

Learn more

The following links provide further information about melatonin. Be aware that websites from other countries may have information that differs from New Zealand recommendations.

Melatonin Pharmac, New Zealand
Circadin  Medsafe consumer information, New Zealand
Melatonin Sleep Health Foundation, Australia


  1. Melatonin New Zealand Formulary
  2. Melatonin New Zealand Formulary for children
  3. Melatonin Pharmac, New Zealand
  4. Melatonin: is it worth losing any sleep over? BPAC, August 2015
  5. Melatonin – don't lose sleep over it SafeRx, 2014
Credits: Sandra Ponen, Pharmacist. Reviewed By: Angela Lambie, Pharmacist, Auckland Last reviewed: 25 Sep 2017