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

Melatonin Starting Dose for Adults

For adults with circadian rhythm disorders like Delayed Sleep-Wake Phase Disorder (DSWPD), start with 3-5 mg of immediate-release melatonin taken between 19:00-21:00 (7-9 PM), but melatonin should NOT be used for chronic insomnia. 1, 2

Critical Context: When NOT to Use Melatonin

• The American Academy of Sleep Medicine explicitly recommends AGAINST using melatonin for chronic insomnia in adults due to minimal efficacy, with only a 9-minute reduction in sleep latency compared to placebo. 1, 2
• For chronic insomnia, use FDA-approved hypnotics (zolpidem 10 mg, eszopiclone 2-3 mg) or cognitive behavioral therapy for insomnia (CBT-I) instead. 2
• The 2 mg doses studied in older adults (>55 years) showed no clinically significant benefit for sleep onset or maintenance, with benefits approximately equal to harms. 1

Recommended Starting Doses by Indication

For Circadian Rhythm Disorders (DSWPD)

• Start with 3-5 mg of immediate-release melatonin taken between 19:00-21:00 (7-9 PM) for at least 28 days to assess efficacy. 1, 2
• The timing is critical: administer 1.5-2 hours before desired sleep onset, not at bedtime—wrong timing can worsen circadian misalignment. 1, 2
• This dosing showed positive results in reducing sleep latency by approximately 38-44 minutes and increasing total sleep time by 41-56 minutes. 1
• This recommendation applies to adults both with and without comorbid depression. 1

For Non-24-Hour Sleep-Wake Rhythm Disorder (N24SWD) in Blind Adults

• Use 0.5-10 mg melatonin (typically start with 5 mg) taken either 1 hour before preferred bedtime or at a fixed time (21:00) for 26-81 days. 2
• This showed an odds ratio for entrainment of 21.18 (95% CI: 3.22-39.17). 2

For Jet Lag

• Use 0.5-5 mg close to target bedtime (10 PM to midnight) at the destination. 3
• 5 mg is more effective than 0.5 mg for faster sleep onset and better sleep quality, though both doses similarly reduce jet lag. 3
• Doses above 5 mg appear to be no more effective. 2, 3

Dosing Principles and Safety

Optimal Therapeutic Range

• The optimal therapeutic range for most circadian disorders is 3-5 mg. 2
• Doses above 10 mg risk receptor desensitization with no additional benefit. 2
• The maximum dose is 12-15 mg, used only for specific conditions like REM sleep behavior disorder. 2

Common Pitfalls to Avoid

• Wrong timing is the most critical error: Taking melatonin early in the day causes sleepiness and delays adaptation to local time. 2, 3
• Avoid slow-release formulations (2 mg prolonged-release) for circadian disorders—immediate-release with a short-lived higher peak concentration works better. 3
• Do not use melatonin in patients with epilepsy or those taking warfarin without careful monitoring, as case reports suggest potential harm. 2, 3

Side Effects

• Common mild side effects include morning headache, morning sleepiness, and gastrointestinal upset. 2
• No serious adverse reactions have been documented across age groups at usual doses. 2
• Higher doses (≥10 mg) appear to have a good safety profile but may increase risk of drowsiness, headache, and dizziness. 4

Clinical Decision Algorithm

1. Identify the indication: Is this chronic insomnia or a circadian rhythm disorder?

   • If chronic insomnia → Do NOT use melatonin; consider FDA-approved hypnotics or CBT-I. 1, 2
   • If DSWPD or circadian disorder → Proceed to step 2.

2. For DSWPD in adults: Start 3-5 mg immediate-release melatonin at 19:00-21:00 (or 1.5-2 hours before desired sleep time) for minimum 28 days. 1, 2

3. For N24SWD in blind adults: Start 5 mg at 21:00 or 1 hour before preferred bedtime for at least 26 days. 2

4. For jet lag: Use 5 mg close to target bedtime at destination, particularly for eastward flights crossing 5+ time zones. 3

5. Monitor for efficacy after the appropriate trial period (28 days for DSWPD, 26+ days for N24SWD). 1, 2