Melatonin

In Aotearoa New Zealand, melatonin is mostly available as:

• Tablets or capsules (1 mg, 2 mg, 3 mg): When you take these, the melatonin is released straight away.
• Modified release tablets (2 mg, 3 mg): 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 written by a prescriber or after a consultation with a pharmacist. 

Prescription from your healthcare provider

If your healthcare provider has prescribed you melatonin and you meet certain criteria (such as being diagnosed with insomnia because of a neurodevelopmental disorder and are under the age of 18 years), you may be eligible to have melatonin funded. Check with your healthcare team. Other people will need to pay for the medicine.

Consultation with your pharmacist

If you're using melatonin for sleep problems, you can buy it from some pharmacies after a consultation with the pharmacist. You need to be 55 years of age or over to be eligible for this service and no more than 13 weeks supply can be given. Only pharmacists who have completed additional training can supply melatonin. To make sure it's safe for you, they'll ask you questions such as other medicines you're taking.

Buying from a pharmacy

It's legal to buy melatonin over the counter in a pharmacy for jet lag but there are no products available to buy yet. As of August 2025 there are some products in the final stages of approval.

Buying melatonin from other countries

Melatonin purchased outside of a pharmacy in Aotearoa New Zealand isn't guaranteed in terms of its quality or safety. All medicines you bring into the country must be declared by New Zealand customs. Read more about buying medicines online.

• 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 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. 
• 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 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.
• Other medicines: Melatonin can interact with other medicines (such as warfarin and oestrogen), 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.

Like all medicines, melatonin can cause side effects, although not everyone gets them. If you're concerned about any symptoms you think might be related to your medicine, talk to your healthcare provider. The following information offers some guidance but doesn't include all possible side effects.

Tell your healthcare provider if these side effects bother you:

• Feeling tired, dizzy, sleepy or drowsy during the day: Avoid driving after taking melatonin.
• Indigestion, nausea (feeling sick), sore tummy, dry mouth: Try taking melatonin with food or a snack.
• Muscle, bone or joint pains.
• Feeling restless, irritable or anxious.
• Headache.
• Chest pain.
• Strange dreams.

Read more about medicines and side effects and reporting a reaction you think might be a side effect.