Melatonin Dosing Recommendations for Adults
For adults with insomnia, the recommended melatonin dose is 2 mg, though this is not strongly supported by evidence as the American Academy of Sleep Medicine suggests against using melatonin for primary insomnia in adults. 1
Adult Dosing Guidelines
- For adults with Delayed Sleep-Wake Phase Disorder (DSWPD), a dose of 5 mg taken between 19:00-21:00 for 28 days is recommended 2
- For general sleep disorders in adults, starting with 3 mg of immediate-release melatonin with dose titration in 3 mg increments if needed is suggested 2
- For elderly patients (>55 years), prolonged-release melatonin at 2 mg has shown some benefit, though the evidence is considered low quality 2, 3
- Doses between 1-6 mg appear effective for improving sleep in older adults, with no clear dose-response relationship identified 4
Pediatric Dosing Guidelines
- For children with DSWPD without comorbidities, use weight-based dosing of 0.15 mg/kg taken 1.5-2.0 hours before habitual bedtime 1, 2
- For children with DSWPD and psychiatric comorbidities, use fast-release melatonin at 3-5 mg (3 mg if <40 kg; 5 mg if >40 kg) 1, 2
Formulation Considerations
- Immediate-release formulations appear more effective than slow-release formulations for sleep onset 2, 5
- Slow-release melatonin (2 mg) was found to be relatively ineffective in clinical trials 6
- Higher doses (5 mg) may help people fall asleep faster and sleep better compared to lower doses (0.5 mg) 6
Treatment Duration
- For adults with DSWPD, a treatment duration of 28 days has shown efficacy 2
- For children without comorbidities, as little as 6 nights of treatment has demonstrated effectiveness 1, 2
- For children with psychiatric comorbidities, a 4-week treatment duration is recommended 1, 2
Pharmacokinetic Considerations
- Lower doses of melatonin may be more effective than higher doses due to potential receptor desensitization with higher doses 7
- The time to maximum concentration (1.3-1.5 hours) and elimination half-life (1.8-2.1 hours) do not differ significantly between low (0.4 mg) and high (4.0 mg) doses 5
- High doses (4 mg) can maintain elevated melatonin levels for approximately 10 hours, which may extend beyond the typical sleep period 5
Safety and Adverse Effects
- No serious adverse reactions have been documented in relation to melatonin use across age groups 1, 2
- Morning grogginess and "hangover" effects are more commonly reported with higher doses 2
- Caution is advised when prescribing to patients taking warfarin and to patients with epilepsy due to potential interactions 2
- Choose reputable formulations (such as USP Verified) when possible for more reliable dosing 2, 8
Clinical Algorithm for Melatonin Use
- For adults with primary insomnia: Not recommended as first-line therapy 1
- For adults with DSWPD: Start with 3-5 mg taken between 19:00-21:00 for at least 28 days 2
- For elderly patients with insomnia: Consider 2 mg prolonged-release formulation 2, 3
- For jet lag prevention: 0.5-5 mg taken at target bedtime at destination (10 pm to midnight) 6