Melatonin Dosage Guide: How Much to Take and When (Canada)

Melatonin is one of the most-searched sleep supplements in Canada, and one of the most misunderstood. Most people assume more is better, take it right as they get into bed, and use it every night for months. None of those habits match how melatonin actually works. Here's a clear, evidence-based guide to how much to take, when to take it, and who should skip it.

The short answer

For most adults, start low: 1–3 mg taken 30–60 minutes before your target bedtime (or 10–30 minutes before bed for sublingual tablets that dissolve under the tongue). Increase only if you need to, and stay within Health Canada's adult range of 0.5–10 mg per day. Use it as needed for occasional sleeplessness, jet lag or a shifted sleep schedule rather than as a permanent nightly habit, and talk to a healthcare provider if you still need it after about four weeks.

What melatonin actually does

Melatonin is a hormone your brain releases in the evening as light fades. It doesn't knock you out like a sedative. Instead, it tells your body that it's night, which helps shift your internal clock and makes it easier to fall asleep at the right time. That's why melatonin works best for timing problems: trouble falling asleep, jet lag, or a schedule that's drifted later than you want. It does much less for waking up repeatedly in the middle of the night.

Health Canada's natural health product monograph for oral melatonin covers three uses: as a sleep aid for occasional sleeplessness, to help reduce the effects of jet lag, and to help reset the sleep-wake cycle in people whose sleep has been restricted or whose schedule has shifted (Health Canada melatonin monograph).

How much melatonin should you take?

Health Canada's monograph allows adults 0.5 to 10 mg per day. In practice, a higher dose isn't necessarily more effective. It just raises your melatonin levels further and for longer, which can leave some people groggy the next morning. A sensible approach:

• Start at 1–3 mg. Many people find this is all they need.
• Give it a few nights before deciding it isn't working. Consistent timing matters more than dose.
• Step up gradually (for example to 5 mg) only if the lower dose clearly isn't helping.
• Don't stack products. If you take a sleep blend that already contains melatonin, count it toward your daily total.

When to take it

Timing is the most common mistake. Taking melatonin right as your head hits the pillow means it peaks after you've already been lying awake. For regular tablets, capsules and liquids, take it 30–60 minutes before your target bedtime. Sublingual (dissolve-under-the-tongue) tablets are absorbed faster, so 10–30 minutes before bed is enough. Never take melatonin earlier in the day: it can make you drowsy at the wrong time and push your body clock in the wrong direction.

For jet lag: take melatonin at the local bedtime at your destination for the first few nights after you arrive. Research reviewed by the U.S. National Center for Complementary and Integrative Health suggests melatonin can reduce overall jet lag symptoms, particularly after eastward flights (NCCIH: Melatonin, What You Need To Know).

Choosing a format

Side effects and who should be cautious

Melatonin appears to be relatively safe for short-term use, but its long-term safety hasn't been established. When side effects happen, they're usually mild: daytime sleepiness, headache, dizziness or nausea (NCCIH). A few practical rules:

• Don't drive or operate machinery after taking melatonin, and avoid combining it with alcohol or other sedatives.
• Talk to your doctor or pharmacist first if you're pregnant or breastfeeding, have epilepsy, take a blood thinner, or take medication for blood pressure, diabetes or immune suppression.
• If sleeplessness lasts longer than about four weeks, see a healthcare provider. Ongoing insomnia can have an underlying cause worth treating directly.

Melatonin for children: what's changed in Canada

Every melatonin natural health product licensed in Canada is labelled for adults only. As of June 2, 2026, Health Canada classifies melatonin for any sleep-related use in children and adolescents under 18 as a prescription drug (Health Canada notice). If your child has trouble sleeping, talk to your family doctor or paediatrician rather than giving them an adult melatonin product.

Melatonin isn't the only option

Because melatonin works on timing, it pairs well with good sleep habits: a consistent wake-up time, dimmer lights and fewer screens in the hour before bed, and a cool, dark bedroom. If muscle tension or a racing mind keeps you up, some people prefer a gentle mineral such as magnesium glycinate instead of, or alongside, melatonin. Our guide to magnesium glycinate vs magnesium citrate explains the difference.

The bottom line

Start with a low dose (1–3 mg), take it 30–60 minutes before bed (10–30 minutes for sublingual), use it as needed rather than indefinitely, and keep it out of reach of children. If you're still struggling after a few weeks, that's the signal to talk to a professional.

Shop melatonin: compare options such as Webber Melatonin Extra Strength sublingual tablets, NFH Melatonin SAP 3 mg, Bioclinic Naturals Melatonin Time Release 3 mg and Adrien Gagnon Melatonin Liquid 3 mg, or browse the full Sleep Support collection.

This article is for general educational purposes and isn't a substitute for personalized medical advice. Read and follow the label, and speak with a healthcare provider before starting any new supplement, especially if you're pregnant, breastfeeding, have a health condition or take prescription medication.