Melatonin

Sounds like 'mel-a-to-nin'

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

Type of medicine

Also called

  • Hypnotic (to improve sleep)
  • 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 is thought to be part of our sleep-wake cycle.
  • A tablet form has been created and used to help with sleep problems in the elderly, shift workers and those with jet lag.
  • While popular, there is limited studies about its long-term safety and interactions data is lacking.
  • Therefore it is only available on prescription in NZ until more research is done.
  • And is only approved for use in primary insomnia (difficulty sleeping) in people over 55 years.
  • It can cause daytime drowsiness and impaired concentration so care is needed
  • It should not be given to children or teens as we do not know if it is safe.

 How to take this medicine

  • Take your melatonin dose 1 or 2 hours before bedtime, with a snack.
  • Swallow melatonin slow release tablets (Circadin®) whole. Do not chew or crush. This will release all the medication at once.
  • When taking melatonin, do not drive or use tools or machines as it may make you sleepy.
  • Limit or avoid alcohol, while taking melatonin. 
  • 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.

Possible side effects

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

Side effectsWhat should I do?
  • Tiredness
  • Drowsiness
  • Be careful when driving or using tools until you know how this medicine affects you.
  • Indigestions, 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

Credits: Sandra Ponen, Pharmacist. Reviewed By: Dr Janine Bycroft, GP.