Maximum Safe Dose of Melatonin
The maximum safe dose of melatonin is 15 mg per day for adults, though lower doses (3-5 mg) are typically recommended as starting doses and are often more effective than higher doses. 1, 2
Recommended Dosing by Age Group
Adults
- Start with 3 mg of immediate-release melatonin for sleep disorders 1
- Dose can be titrated in 3 mg increments if needed, up to a maximum of 15 mg 2
- For adults with Delayed Sleep-Wake Phase Disorder (DSWPD), 5 mg taken between 19:00-21:00 for 28 days is recommended 1
- For elderly patients (>55 years), a lower dose of 2 mg prolonged-release melatonin may be sufficient 1
Children
- For children with DSWPD without comorbidities: 0.15 mg/kg taken 1.5-2.0 hours before habitual bedtime 1
- For children with DSWPD and psychiatric comorbidities: 3 mg if <40 kg and 5 mg if >40 kg 1
- Effective doses range from 0.5 to 3 mg in children and 3 to 5 mg in adolescents 3
Why Lower Doses May Be More Effective
- Higher doses (10 mg+) may cause receptor desensitization or saturation, potentially disrupting normal circadian signaling mechanisms 2
- Morning grogginess and "hangover" effects are more commonly reported with higher doses 2
- Gastrointestinal upset has been reported more frequently at higher melatonin doses 2
- Immediate-release formulations appear more effective than slow-release formulations for sleep onset 1
Safety Profile
- No serious adverse events have been documented in relation to melatonin use across age groups 1, 4
- Most common adverse events reported in clinical trials include daytime sleepiness (1.66%), headache (0.74%), dizziness (0.74%), and hypothermia (0.62%) 4
- Most adverse events resolve spontaneously within a few days or immediately upon withdrawal of treatment 4
- A systematic review of high-dose melatonin (≥10 mg) found it appears to have a good safety profile, though it may increase the risk of minor adverse events such as drowsiness, headache, and dizziness 5
Special Considerations and Precautions
- Caution is advised when prescribing to patients taking warfarin and to patients with epilepsy due to potential interactions 1, 6
- Timing of administration is critical - taking melatonin at the wrong time (early in the day) can cause sleepiness and delay adaptation to local time 6
- Choose United States Pharmacopeial Convention Verified formulations when possible for more reliable dosing 1
- Long-term safety data beyond several months is limited, though available evidence suggests good tolerability 7
Optimal Administration for Maximum Effectiveness
- Administer 1.5-2 hours before desired bedtime for optimal phase-advancing effects 8
- Consistency in timing is crucial - administering melatonin at the same time each day relative to desired bedtime improves outcomes 8
- For jet lag prevention, melatonin taken close to the target bedtime at the destination (10pm to midnight) is effective, with daily doses between 0.5 and 5 mg showing similar effectiveness 6
While melatonin appears safe even at higher doses, the evidence suggests that lower doses (3-5 mg) are often as effective or more effective than higher doses, with fewer side effects. Starting with lower doses and titrating up only if necessary is the recommended approach.