In this guide
What is melatonin?
Melatonin is a nighttime hormone that signals darkness to the circadian system. A dose at a specific clock time can shift the body clock; a dose near bedtime can also promote sleepiness. These effects do not make every sleep problem interchangeable.
The useful protocol depends on diagnosis, formulation and time. Confirmed delayed sleep phase does not use the same protocol as primary insomnia in an older adult, and cognitive behavioural therapy for insomnia remains the primary intervention for chronic insomnia. [1][2][3]
Typical Melatonin Protocols
| Source and context | Form | Amount | Frequency and timing | Duration | Observed result |
|---|---|---|---|---|---|
| Sletten 2018 · confirmed delayed sleep phase | Fast-release melatonin | 0.5 mg | 1 hour before desired bedtime, at least 5 consecutive nights of 7 | 4 weeks with sleep-wake scheduling | Actigraphic sleep onset 34 minutes earlier than placebo 116 randomized; both groups also received behavioural scheduling, so the effect is not a capsule-only result. |
| Wade 2010 · primary insomnia | Prolonged-release melatonin | 2 mg | Once nightly, 1 to 2 hours before bedtime, after food | 3 weeks then 26-week extension | Age 65 to 80 subgroup: latency -19.1 versus -1.7 minutes at 3 weeks 791 adults randomized after placebo run-in; low endogenous output did not predict response; manufacturer funding and authorship. |
| AASM 2017 · adult chronic insomnia | Melatonin, mainly 2 mg trials | 2 mg in the reviewed evidence | Trial schedules, not converted into personal advice | Varied | Weak recommendation against use for sleep-onset or sleep-maintenance insomnia The guideline rated evidence very low and identifies CBT-I as a primary intervention. |
No RDA, AI or UL exists. Melatonin is a hormone, not an essential nutrient.
- Diagnostic
- Separate insomnia, delayed phase and jet lag.
- Formulation
- Record fast or prolonged release.
- Timing
- Keep exact clock time relative to bedtime.
- Light
- Record evening and morning light.
The protocol is a clock
What is melatonin commonly used for?
The clearest separated uses are circadian delay, jet lag and selected insomnia contexts. In delayed sleep phase, a small timed dose plus a fixed schedule improved sleep-onset time. [1]
For adult chronic insomnia, AASM judged average benefit too uncertain to recommend melatonin. This does not erase the prolonged-release trial in older adults; the populations, formulations and targets differ. [2][3]
Which forms and labels matter?
Fast release gives a short exposure and can serve as a timing signal. Prolonged release aims to extend exposure through the night. Gummies, liquids, sublingual tablets and blends are not equivalent.
Erland and Saxena tested 31 products bought in Ontario: content ranged from 83% below label to 478% above; eight contained 1 to 75 μg serotonin. Lot, certification and formulation matter. [4]
What does the human evidence show?
Sletten randomized 116 adults with delayed sleep phase and late endogenous melatonin rhythm. With 0.5 mg 1 hour before desired bedtime and behavioural scheduling in both groups, actigraphic sleep onset occurred 34 minutes earlier than placebo. DLMO did not differ in the measured post-treatment subset. [1]
Wade randomized 791 adults with primary insomnia to 2 mg prolonged-release or placebo after a 2-week placebo run-in. The primary endpoint did not differ in low melatonin excretors across ages; it favoured ages 65 to 80. Reported benefits persisted in extension without a tolerance or withdrawal signal. [2]
AASM synthesized 2 mg trials and issued a weak recommendation against melatonin for adult chronic insomnia, with very-low-quality evidence. [3]
How does melatonin work?
Melatonin primarily binds MT1 and MT2 receptors and signals biological night. Chronobiotic effects depend on circadian phase: dosing at the wrong time can be ineffective or shift the clock in an unwanted direction.
Acute sleepiness and a circadian phase shift are distinct. A higher dose does not guarantee a better timed signal or better sleep.
What are the risks and interactions?
Daytime sleepiness, dizziness, headache, vivid dreams and reduced alertness can occur. Do not drive when drowsy. Alcohol and sedatives may add impairment; interactions can involve anticoagulants, anticonvulsants, immunosuppressants, diabetes medicines and contraceptives.
Pregnancy, breastfeeding, epilepsy, autoimmune disease, liver disease or fall risk call for clinical review. Real product variability adds dose uncertainty. [4]
Regulatory status in the United States and Canada
In the United States, melatonin is sold as a dietary supplement. In Canada, licensed NHPs are adult-only; since June 2, 2026, every sleep-related use under age 18 is prescription-only. Slenyto remains the specific authorized pediatric medicine for ages 2 to under 18 with autism or Smith-Magenis syndrome. [5]
What should be monitored?
Record actual dose, formulation, dose time, bedtime, sleep onset, waking, morning drowsiness, evening light, caffeine and workdays. For a circadian target, preserve timing instead of changing dose and time together.
What happens after stopping?
No classic withdrawal syndrome is established. The underlying sleep problem may return; prolonged-release trials did not show marked rebound. [2]
How should it be stored?
Store dry, away from heat and out of children’s reach. Keep the label and lot.
Community experiences
“Stopped working” can reflect changing clock time, late light, a different formulation or a different lot. Stories often fail to distinguish insomnia, delayed phase and insufficient sleep.
How does melatonin compare with other approaches?
CBT-I targets behaviours and associations that maintain chronic insomnia. Morning light and stable scheduling target the circadian clock. Prescription hypnotics have different benefits and risks. The choice depends on the actual disorder, not sleep difficulty alone.
Frequently asked questions
When should it be taken?
Timing depends on the target. Sletten used 0.5 mg 1 hour before desired bedtime; that does not generalize to everyone. [1]
Are more milligrams better?
No. A small timed dose worked in delayed phase, and products may already exceed their labels. [1][4]
Does it help chronic insomnia?
AASM gives a weak recommendation against general use for adult insomnia. [3]
Is it authorized for children in Canada?
Since June 2, 2026, every sleep-related use under age 18 is prescription-only. [5]
What is Slenyto?
It is the Canadian prescription medicine authorized for insomnia in ages 2 to under 18 with autism or Smith-Magenis syndrome, not a general pediatric authorization. [5]
Can it be stopped without tapering?
Longer trials did not show important rebound or withdrawal, but the underlying sleep problem may return. [2]
Glossary
Terms used in this guide.
- Circadian
- Biological rhythm near 24 hours.
- DLMO
- Dim-light melatonin onset, a phase marker.
- CBT-I
- Cognitive behavioural therapy for insomnia.
- Fast release
- Form designed for shorter exposure.
- Prolonged release
- Form designed to extend release overnight.
How this guide was researched
This guide prioritizes two open randomized trials, the AASM guideline, Canadian product analysis and final June 2, 2026 regulatory notice. Identities and correction fields were checked October 9, 2026.
How this guide was made
Method and evidence gaps
Dose, formulation, clock time, diagnosis and endpoint were kept together. Open trial full texts and official sources were read.
Gaps: long-term safety by age, formulation comparisons, current product quality and applicability to each sleep disorder.
Sources
Start with the timed protocol, then compare insomnia, product quality and Canada’s rule.
Showing 5 sources
- 01
Efficacy of melatonin with behavioural sleep-wake scheduling for delayed sleep-wake phase disorder: A double-blind, randomised clinical trial. ↗
Double-blind randomized trial
116 adults; 0.5 mg fast release 1 hour before desired bedtime for 4 weeks with behavioural scheduling.
- 02
Nightly treatment of primary insomnia with prolonged release melatonin for 6 months: a randomized placebo controlled trial on age and endogenous melatonin as predictors of efficacy and safety. ↗
Randomized trial with extension
791 randomized; 2 mg prolonged release 1 to 2 hours before bed; benefit mainly ages 65 to 80.
- 03
Clinical Practice Guideline for the Pharmacologic Treatment of Chronic Insomnia in Adults: An American Academy of Sleep Medicine Clinical Practice Guideline. ↗
Clinical practice guideline
Weak recommendation against melatonin for adult chronic insomnia; very-low-quality evidence.
- 04
Melatonin Natural Health Products and Supplements: Presence of Serotonin and Significant Variability of Melatonin Content. ↗
Product quality analysis
31 products; -83% to +478% of label, with serotonin in eight.
- 05
Health Canada has changed the Prescription Drug List qualifier related to pediatric melatonin use ↗
Official regulatory notice
From June 2, 2026, all sleep-related use under 18 is prescription-only in Canada.
No matching sources
Try a different term or show the full list.