Melatonin Dosing for Healthy Adults
For healthy adults without underlying medical conditions, start with 3 mg of immediate-release melatonin taken 1.5-2 hours before desired bedtime, and if ineffective after 1-2 weeks, increase in 3 mg increments up to a maximum of 10-15 mg. 1, 2, 3
Starting Dose and Timing
- Begin with 3 mg of immediate-release melatonin as the initial dose, as recommended by the American Academy of Sleep Medicine 1, 2
- Take the dose 1.5-2 hours before your target bedtime for optimal circadian phase-shifting effects 1, 2
- Timing is critical—taking melatonin early in the day will cause sleepiness and worsen circadian misalignment 1
Dose Escalation Strategy
- If 3 mg is ineffective after 1-2 weeks, increase by 3 mg increments up to a maximum of 10-15 mg 1, 2, 3
- The typical effective range is 3-5 mg for most adults 1, 4
- Doses above 10 mg may cause receptor desensitization or saturation, potentially reducing effectiveness 2, 3
Important Dosing Principles
- Lower doses (0.5-3 mg) can be more effective than higher doses due to receptor physiology 2, 5
- Higher doses (≥10 mg) are associated with more frequent adverse effects like morning headache, drowsiness, and gastrointestinal upset 2, 6, 7
- Immediate-release formulations are more effective than slow-release for sleep onset 8, 1
Duration of Use
- Melatonin should not be used long-term for chronic insomnia beyond 3-4 months due to insufficient safety data, according to the American Academy of Sleep Medicine 1, 3
- Most clinical trial data supports use for 4 weeks or less 1
- For circadian rhythm disorders (not simple insomnia), longer-term use may be appropriate with periodic reassessment every 3-6 months 1, 3
Safety Considerations and Contraindications
- Use with extreme caution in patients taking warfarin due to documented case reports of interactions 1, 2, 3
- Exercise caution in patients with epilepsy based on World Health Organization case reports 1, 2, 3
- Monitor for impaired glucose tolerance, particularly in those with diabetes risk factors 1
- Common mild side effects include daytime sleepiness (1.66%), headache (0.74%), and dizziness (0.74%) 6, 7
Product Quality Concerns
- Choose United States Pharmacopeial Convention (USP) Verified formulations when possible 1, 2, 3
- Melatonin is regulated as a dietary supplement in the U.S., raising significant concerns about purity and reliability of stated doses 1, 3
- Different formulations can lead to variable efficacy between brands 1
Critical Pitfalls to Avoid
- Do not use melatonin as first-line treatment for chronic insomnia—the American Academy of Sleep Medicine explicitly recommends against this due to weak evidence 8, 1, 3
- Do not take melatonin in the morning or afternoon (except for specific circadian rhythm disorders), as this worsens circadian misalignment 1
- Avoid alcohol consumption, which interacts with melatonin 1
- Avoid excessive caffeine after 2:00 PM, as this counteracts melatonin's effects 1
When Melatonin is Most Appropriate
- Melatonin works best for circadian rhythm disorders (delayed sleep-wake phase disorder, jet lag, shift work disorder) rather than primary insomnia 1, 3
- For jet lag crossing 5+ time zones, melatonin is remarkably effective with a number needed to treat (NNT) of 2 9
- The benefit is greater for eastward flights and when crossing more time zones 9
Evidence Quality Note
The American Academy of Sleep Medicine rates the evidence for melatonin in primary insomnia as low to very low quality due to imprecision, heterogeneity, and potential publication bias 8. Studies show minimal improvements in sleep latency (8.9 minutes), total sleep time (2.2 minutes), and no improvement in wake after sleep onset 8. This explains why melatonin receives a weak recommendation against use for chronic insomnia, despite its popularity 8, 1.