What is the recommended dose of melatonin (melatonin) for adults?

Melatonin Dosing for Adults

The American Academy of Sleep Medicine does not recommend melatonin for the treatment of chronic insomnia in adults, as trials using 2 mg doses showed no clinically significant benefit for sleep onset or maintenance. 1

Context-Specific Dosing Recommendations

For Chronic Insomnia (NOT Recommended)

• The American Academy of Sleep Medicine explicitly advises against using melatonin for chronic insomnia based on very low quality evidence from trials using 2 mg doses in older adults (>55 years). 1
• Meta-analysis showed no clinically significant improvements in sleep latency, total sleep time, wake after sleep onset, or sleep quality at this dose. 1
• The benefits were judged approximately equal to harms, making it an ineffective choice for this indication. 1

For Delayed Sleep-Wake Phase Disorder (DSWPD) - Recommended

For adults with DSWPD, use 5 mg of melatonin timed between 19:00-21:00 (7-9 PM) for at least 28 days. 1

• This represents a weak recommendation based on low-quality evidence, but showed positive results in reducing sleep latency by approximately 38-44 minutes and increasing total sleep time by 41-56 minutes. 1
• The timing is critical: administer 1.5-2 hours before desired sleep onset, not at bedtime. 1
• This recommendation applies to adults both with and without comorbid depression. 1

Dosing Considerations from Research Evidence

Standard Dosing Range

While guidelines are restrictive, research literature suggests:

• Low doses: 0.3-3 mg are commonly studied. 2, 3
• High doses: 5 mg showed superior efficacy in older adults, increasing sleep efficiency during both biological day and night by extending Stage 2 NREM sleep. 3
• Doses ≥10 mg appear safe based on meta-analysis, though they increase minor adverse events (drowsiness, headache, dizziness) without increasing serious adverse events. 4

Age-Related Dosing Patterns from Literature

• Adults: 1-5 mg range most commonly studied. 2
• Older adults (>55 years): 2-6 mg range, with 5 mg showing better efficacy than lower doses. 2, 3

Critical Clinical Caveats

Timing matters more than dose for circadian disorders. 1 Melatonin administered during the biological day (when endogenous levels are low) is more effective than nighttime administration when endogenous melatonin is already present. 3

Product quality is unregulated in the U.S. Melatonin is classified as a dietary supplement with no FDA oversight of manufacturing, leading to substantial variability between labeled and actual content. 5

Pharmacokinetics in older adults: Both 0.4 mg and 4 mg doses show similar elimination half-lives (1.8-2.1 hours), but 4 mg maintains levels >50 pg/mL for approximately 10 hours, potentially extending effects beyond the sleep period. 6

Practical Algorithm

1. First, identify the indication:

   • Chronic insomnia → Do not use melatonin; consider FDA-approved hypnotics or CBT-I instead. 1, 7
   • DSWPD or circadian rhythm disorder → Proceed with melatonin 5 mg. 1

2. For DSWPD, implement strategic timing:

   • Administer 5 mg between 19:00-21:00 (or 1.5-2 hours before desired sleep time). 1
   • Continue for minimum 28 days to assess efficacy. 1

3. Monitor for mild adverse effects:

   • Drowsiness, headache, dizziness are most common but generally resolve with discontinuation. 4, 5
   • Long-term use (up to 6 weeks studied) shows stable renal and hepatic function. 6