Melatonin Dosing for Sleep Disturbances
The American Academy of Sleep Medicine explicitly recommends AGAINST using melatonin for chronic insomnia in adults due to minimal efficacy, but when used for circadian rhythm disorders like Delayed Sleep-Wake Phase Disorder, start with 3-5 mg of immediate-release melatonin taken between 19:00-21:00 for at least 28 days. 1, 2, 3
Critical Context: When NOT to Use Melatonin
For primary insomnia (difficulty falling or staying asleep without circadian misalignment), melatonin performs poorly and should NOT be used. 1, 3 The evidence shows only a 9-minute reduction in sleep latency compared to placebo, with very low quality evidence. 3 Instead, consider FDA-approved hypnotics like zolpidem 10 mg, eszopiclone 2-3 mg, or temazepam 15 mg for sleep onset and maintenance insomnia. 1
When Melatonin IS Appropriate: Circadian Rhythm Disorders
Adult Dosing for Delayed Sleep-Wake Phase Disorder (DSWPD)
- Start with 3-5 mg immediate-release melatonin 2, 3
- Timing: Between 19:00-21:00 (7-9 PM) 2, 3
- Duration: Minimum 28 days to assess effectiveness 2, 3
- Maximum dose: 12-15 mg (doses above 10 mg risk receptor desensitization with no additional benefit) 2, 4
Pediatric Dosing for DSWPD
Without comorbidities:
- Weight-based: 0.15 mg/kg 2, 3
- Timing: 1.5-2.0 hours before habitual bedtime 2, 3
- Duration: Minimum 6 nights 2, 3
With psychiatric comorbidities (including autism spectrum disorders):
Elderly Patients (>55 years)
- Prolonged-release melatonin 2 mg may provide modest benefit, though evidence quality is low 2, 3
- The recommendation against melatonin for primary insomnia still applies to elderly patients 3
Why Lower Doses Can Be More Effective
Higher doses (≥10 mg) may cause receptor desensitization or saturation, disrupting normal circadian signaling. 4 Start with 3 mg and titrate in 3 mg increments only if needed after 1-2 weeks. 2, 4 Morning grogginess and "hangover" effects occur more frequently with higher doses due to melatonin's half-life extending into morning hours. 4
Immediate-Release vs. Prolonged-Release
Immediate-release formulations are more effective than slow-release for sleep onset. 2 Slow-release melatonin (2 mg) showed minimal efficacy in trials, leading to the weak recommendation against its use. 1, 2
Safety Profile and Contraindications
No serious adverse reactions have been documented across age groups, but common mild side effects include morning headache, morning sleepiness, and gastrointestinal upset. 2, 3, 4
Specific cautions:
- Warfarin users: Use with caution due to potential interactions 2, 3, 4
- Epilepsy: Exercise caution based on case reports 2, 3, 4
- Dementia patients: Avoid melatonin for irregular sleep-wake rhythm disorder due to lack of benefit and potential harm 4
Duration of Treatment
For chronic insomnia, limit use to 3-4 months maximum due to insufficient long-term safety data beyond several months. 3, 4 However, for circadian rhythm disorders requiring ongoing chronobiotic therapy, longer-term use may be appropriate with periodic reassessment every 3-6 months. 4
In pediatric populations with autism spectrum disorders, safe use has been documented for up to 24 months with continued efficacy. 4
Product Quality Concerns
Melatonin is regulated as a dietary supplement in the U.S., raising concerns about purity and reliability of stated doses. 2, 3, 4 Choose United States Pharmacopeial Convention Verified formulations when possible for more reliable dosing. 2, 3
Critical Timing Warning
Taking melatonin at the wrong time (morning or afternoon) will worsen circadian misalignment and potentially reduce effectiveness. 4 The timing must align with the desired sleep phase shift—typically 1.5-2 hours before desired bedtime for DSWPD. 2, 3