Sleep health education

Melatonin in Canada: Rules, Safety and When It Helps

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Quick answer

In Canada, melatonin is sold without a prescription as a natural health product for adults only. Since June 2, 2026, melatonin for sleep in anyone under 18 requires a prescription (Health Canada). Melatonin may help with jet lag and some body-clock problems, but the evidence for chronic insomnia is mixed, and cognitive behavioural therapy for insomnia (CBT-I) is the recommended first treatment. Melatonin does not treat sleep apnea.

At a glance

Key takeaways

Takeaway 1

Adult melatonin is available over the counter in Canada; for anyone under 18 it now needs a prescription.

Takeaway 2

Melatonin is most useful for jet lag and delayed body-clock timing, not for long-term insomnia.

Takeaway 3

Supplement labels are not always accurate: tested products ranged from 83% less to 478% more melatonin than the label stated.

Takeaway 4

If you snore, gasp or feel sleepy during the day, melatonin will not help; ask about sleep apnea testing.

Why melatonin for children now needs a prescription

Health Canada says a health professional should first look for underlying causes of a child’s sleep problems, recommend healthy sleep habits, and set an appropriate dose if melatonin is still needed (Health Canada). If your child has trouble sleeping, talk to their doctor or nurse practitioner rather than using an adult product.

What melatonin can and cannot do

Melatonin is a hormone that signals night-time to your body clock. It is not a strong sedative.

  • Jet lag: reviews suggest it may help (U.S. National Center for Complementary and Integrative Health).
  • Delayed sleep timing (falling asleep very late and struggling to wake): it appears to help some people, although the balance of benefit and harm is less clear.
  • Chronic insomnia: results are mixed. A Canadian review found mixed evidence compared with placebo (CADTH), and Alberta Health Services notes a lack of quality evidence for over-the-counter melatonin in adult insomnia (AHS). CBT-I is the recommended first treatment; see insomnia.
  • Sleep apnea: melatonin does not treat it. Take our sleep apnea quiz if you snore or feel sleepy during the day.

Dose and label accuracy

Adult melatonin products in Canada are typically labelled for doses between 0.1 mg and 10 mg, taken at or before bedtime (Rexall, summarizing Health Canada’s monograph). Start with the lowest dose on the label and follow its directions.

Labels are not always accurate. In a study cited by Alberta Health Services, melatonin content ranged from 83% below to 478% above the labelled amount, and 8 of 30 products contained serotonin (AHS). Choose a product with an NPN from a pharmacy you trust.

Is melatonin safe?

Melatonin is generally well tolerated for short-term use in adults. Common side effects include headache, dizziness, nausea and sleepiness (NCCIH). Canadian labels advise not driving or operating machinery for 5 hours after taking it, and not using it during pregnancy or breastfeeding (Rexall). Talk to a pharmacist before using melatonin if you take blood thinners, seizure medication, diabetes or blood pressure medication, sedatives or immunosuppressants, and see a health professional if you need it for more than four weeks.

What about magnesium for sleep?

Magnesium is often promoted for sleep, but the evidence is thin and the studies are small (Cleveland Clinic). Health Canada sets the upper limit for adults at 350 mg a day from supplements, not counting food (Health Canada). Higher doses can cause diarrhea and cramps. People with kidney disease, and people taking some antibiotics, osteoporosis medicines or diuretics, should ask a pharmacist before taking magnesium.

When sleep problems need more than a supplement

Could this be sleep apnea?

Healthy habits help most people sleep better, but they will not fix sleep apnea. Consider getting checked if you have any of these:

  • loud snoring, or someone has noticed you stop breathing or gasp in your sleep;
  • you wake unrefreshed or with a headache, even after enough hours in bed;
  • you doze off easily during the day, especially while driving.

Take the 2-minute sleep apnea quiz or order a home sleep test ($165, no referral needed).

Common questions

Frequently asked questions

Do you need a prescription for melatonin in Canada?

Not for adults. Melatonin natural health products are sold over the counter for adults. Since June 2, 2026, melatonin for sleep in anyone under 18 requires a prescription.

Can I give my child melatonin in Canada?

Only with a prescription from a doctor or nurse practitioner, who will first check for causes of the sleep problem and set a dose. Adult products are not indicated for children.

How much melatonin should an adult take?

Canadian adult products are typically labelled for 0.1 to 10 mg at or before bedtime. Start low, follow the label and ask a pharmacist if you take other medicines.

Does melatonin help insomnia?

The evidence is mixed. It may help a little for some people, but CBT-I is the recommended first treatment for chronic insomnia.

Can melatonin help sleep apnea?

No. Sleep apnea is a breathing problem during sleep and needs testing and treatment such as CPAP. Melatonin does not treat it.

Sources

Disclaimer

This page is general health information, not medical advice, and it does not replace an assessment by a qualified health professional. Virtual Sleep Care does not currently serve Quebec, Yukon, the Northwest Territories or Nunavut. Ask a pharmacist or health professional before starting any supplement.

Next step

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