Melatonin

In Aotearoa New Zealand, melatonin is mostly available as:

• Tablets or capsules (1mg, 2mg, 3mg). When you take these, the melatonin is released straight away.
• Modified release tablets (2mg, 3mg). Modified release (also called slow release) means that the medicine is released slowly over several hours.

To ensure the safe use of melatonin supplements, you can only get melatonin through a prescription from your doctor or after a consultation with a pharmacist. 

• Do you have an autoimmune disease (a condition in which your 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?
• Are you taking any other medicines?

If you answered yes to any of these questions, it’s important that you tell your healthcare provider 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.

• Timing for sleep problems:
  • Take your melatonin dose right before bedtime or, for slow release tablets, take 1 or 2 hours before bedtime.
  • Take with or straight after a meal or snack. 
  • It's important to take your dose at the correct time. If taken at the wrong time of the day it's likely to cause daytime sleepiness – particularly if combined with other medicines.
• Swallow slow-release tablets whole: Don't crush, chew or divide them because this will release all the medicine at once. The slow-release tablets have been designed to release the right dose of medicine while you sleep. If you crush, chew or divide the tablet the melatonin can be released straight away so it will work too quickly.
• Effects of melatonin may not be immediate: It may take a few days for you to experience the full benefits. It's important to take your dose regularly.
• Missed dose: It's not harmful if you miss your dose. If you forget to take your melatonin at the usual time, but remember before you go to sleep, take it when you remember. But if you don't remember until the following day, just take the next dose at the right time. Don't take double the dose.
• Don't take melatonin for longer than your healthcare provider advises: Melatonin doesn't work for everyone, so see your healthcare provider if you have finished your treatment course but keep having sleep problems. 

Find out about ways to improve your sleep and sleep-related behaviours. 

Here are some things to know when you're taking melatonin. Other things may be important as well, so ask your healthcare provider what you should know about.

• Alcohol: Limit or avoid alcohol while taking melatonin because alcohol can affect how it works.
• Caffeine: Avoid products with caffeine in them as caffeine can affect how melatonin works.
• Smoking: Tobacco smoking affects melatonin levels. If you smoke, your healthcare provider can advise you on the best dose of melatonin.
• Effects on driving: Avoid driving after taking melatonin.
• Interaction with other medicines: Melatonin can interact with other medicines, herbal supplements and rongoā Māori so check with your healthcare provider or pharmacist before starting melatonin or before starting any new products. This is especially important if you are taking other medicines that can cause drowsiness or if you are taking warfarin (as it may alter the INR) or any medicines containing oestrogen.

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.