What is the recommended dosage of melatonin (a sleep hormone regulator) for a patient using it as a sleep supplement?

Melatonin Dosing for Sleep Supplementation

The American Academy of Sleep Medicine recommends starting with 3 mg of immediate-release melatonin taken 1.5-2 hours before desired bedtime, with dose titration in 3 mg increments only if needed, up to a maximum of 15 mg, though notably the AASM suggests against using melatonin as first-line treatment for chronic insomnia due to weak evidence showing benefits approximately equal to harms. 1, 2

Critical Guideline Position

• The 2017 American Academy of Sleep Medicine clinical practice guideline explicitly recommends against using melatonin for sleep onset or sleep maintenance insomnia in adults, based on trials of 2 mg doses showing very low quality evidence with harms approximately equal to benefits 1
• This negative recommendation creates a paradox for clinicians, as melatonin remains widely used despite guideline recommendations against it for primary insomnia 2

Evidence-Based Dosing Algorithm

Starting Dose:

• Begin with 3 mg immediate-release melatonin administered 1.5-2 hours before desired bedtime 2, 3
• Lower doses (0.5-3 mg) may actually be more effective than higher doses due to receptor desensitization and saturation that occurs with doses of 10 mg or higher 2

Dose Escalation (if needed after 1-2 weeks):

• Increase by 3 mg increments if initial dose proves ineffective 2
• Maximum recommended dose: 15 mg 2
• For REM sleep behavior disorder specifically, doses range from 3-12 mg at bedtime 2, 3

Timing Considerations:

• Optimal administration is 1.5-2 hours before habitual bedtime 2, 3
• Some evidence suggests administration at 6 PM (approximately 1-2 hours before bedtime) optimizes circadian regulation 4
• Never administer in morning or afternoon, as this worsens circadian misalignment 2

Why Lower Doses May Be Superior

• Melatonin works by binding to M1 and M2 receptors to suppress REM sleep motor tone and normalize circadian features 2
• Higher doses (10 mg) cause receptor desensitization or saturation, potentially disrupting normal circadian signaling 2
• Morning grogginess and "hangover" effects occur more frequently with higher doses due to melatonin's half-life extending into morning hours 2
• Clinical trials show higher doses (10 mg) associated with more frequent adverse effects including morning headache and sleepiness 2

Duration of Treatment Limitations

• The AASM recommends against long-term use beyond 3-4 months for chronic insomnia due to insufficient safety and efficacy data 2
• Most clinical trial data supports melatonin use lasting 4 weeks or less 2
• If using long-term, periodic attempts to reduce frequency and dose every 3-6 months are indicated 2
• Consider tapering to every other or every third night rather than daily use 2

Special Population Considerations

Elderly Patients (>55 years):

• Prolonged-release melatonin at 2 mg has shown some benefit, though evidence is low quality 3
• This is the only population where the 2 mg dose studied in AASM guidelines might be appropriate 1, 3

Children:

• Initial dose 1-3 mg for typical development, 30-60 minutes before bedtime (maximum 6 mg) 2
• For autism spectrum disorder: start with 1 mg, 30-40 minutes before bedtime 2
• Weight-based dosing: 0.15 mg/kg for children without comorbidities 2, 3

Critical Safety Warnings

• Use with caution in patients taking warfarin due to potential interactions reported to WHO 2, 3
• Exercise caution in patients with epilepsy based on case reports 2, 3
• Melatonin has been associated with impaired glucose tolerance in healthy individuals after acute administration 2
• Avoid in older adults with dementia for irregular sleep-wake rhythm disorder due to detrimental effects on mood and daytime functioning 2

Product Quality Concerns

• Melatonin is regulated as a dietary supplement in the U.S., not as a medication, raising significant concerns about purity and reliability of stated doses 2
• Choose United States Pharmacopeial Convention Verified formulations for more reliable dosing and purity 2, 3
• Different formulations show variable efficacy between brands 2

Formulation Selection

• Immediate-release formulations are preferred over slow-release for sleep onset issues, as slow-release appears less effective for sleep onset 3
• Prolonged-release formulations may help with sleep maintenance but show less benefit for sleep latency 2

Common Pitfalls to Avoid

• Do not use doses above 10 mg routinely, as receptor desensitization reduces effectiveness 2, 3
• Do not use as first-line therapy for chronic insomnia per AASM guidelines—consider cognitive behavioral therapy for insomnia (CBT-I) first 1, 2
• Do not combine with alcohol, which interacts with melatonin and reduces efficacy 2
• Avoid excessive caffeine after 2:00 PM, as this counteracts melatonin's effects 2

Realistic Expectations

• Melatonin reduces sleep latency by approximately 28-42 minutes 2
• Total sleep time increases by approximately 1.8-2.6 hours in responsive populations 2
• Effects are modest for most people, and sleep architecture remains unchanged 5
• Recent N-of-1 trials show melatonin supplements (0.5 mg and 3.0 mg) did not significantly improve sleep duration or quality in many individuals 6