What is a reasonable starting dose of melatonin (melatonin) for adults?

Starting Dose of Melatonin for Adults

For adults, start with 3-5 mg of immediate-release melatonin if treating a circadian rhythm disorder like Delayed Sleep-Wake Phase Disorder, but do not use melatonin at all for chronic insomnia—it doesn't work. 1, 2, 3

Critical First Decision: What Are You Treating?

The starting dose depends entirely on the indication, as melatonin's efficacy varies dramatically by condition:

For Chronic Insomnia: DO NOT USE

• The American Academy of Sleep Medicine explicitly recommends AGAINST using melatonin for chronic insomnia in adults. 1, 3
• Trials using 2 mg doses showed no clinically significant benefit for sleep onset, maintenance, or quality—only a 9-minute reduction in sleep latency compared to placebo. 1, 3
• The evidence quality is very low, and benefits approximately equal harms. 1
• Instead, use FDA-approved hypnotics (zolpidem, eszopiclone) or cognitive behavioral therapy for insomnia (CBT-I). 1, 3

For Delayed Sleep-Wake Phase Disorder (DSWPD): START WITH 3-5 MG

• Begin with 3-5 mg of immediate-release melatonin taken between 19:00-21:00 (7-9 PM) for at least 28 days. 1, 2, 3
• The American Academy of Sleep Medicine specifically recommends 5 mg for this indication. 1, 2
• Timing is critical: administer 1.5-2 hours before desired sleep onset, NOT at bedtime. 1, 2
• This regimen reduced sleep latency by 38-44 minutes and increased total sleep time by 41-56 minutes in trials. 1
• This is a weak recommendation based on low-quality evidence, but represents the best available option. 1

For Non-24-Hour Sleep-Wake Rhythm Disorder (Blind Adults): START WITH 5 MG

• Use 5 mg taken either 1 hour before preferred bedtime or at a fixed time (21:00) for 26-81 days. 3
• This showed an odds ratio for entrainment of 21.18 (95% CI: 3.22-39.17). 3

Dosing Principles and Boundaries

Effective Dose Range

• The optimal therapeutic range for most circadian disorders is 3-5 mg. 3
• Doses between 0.5-5 mg are similarly effective for jet lag, except people fall asleep faster with 5 mg than 0.5 mg. 4
• Lower doses (0.3 mg) may work for daytime sleep but are less effective for nighttime sleep in older adults. 5

Maximum Dose Considerations

• The maximum recommended dose is 12-15 mg, reserved only for specific conditions like REM sleep behavior disorder (3-12 mg range). 2, 3
• Doses above 10 mg risk receptor desensitization with no additional benefit. 2, 3
• Higher doses (≥10 mg) increase adverse effects like drowsiness, headache, and dizziness without improving efficacy. 6

Formulation Matters

• Use immediate-release formulations, not slow-release. 1, 2
• Slow-release melatonin (2 mg) appears less effective than immediate-release for sleep onset. 2
• The 2 mg prolonged-release formulation showed minimal benefit even in elderly patients (>55 years). 2, 3

Special Population: Elderly Adults

• For elderly patients with insomnia, melatonin still should NOT be used based on American Academy of Sleep Medicine guidelines. 2, 3
• If treating a circadian disorder in elderly patients, use the same 3-5 mg dose as younger adults. 2, 3
• One study showed 5 mg increased sleep efficiency during both day and night in older adults (>55 years), primarily by increasing Stage 2 sleep. 5

Common Pitfalls to Avoid

Wrong Timing = Treatment Failure

• If taken early in the day at the wrong time, melatonin causes sleepiness and delays adaptation to local time. 3, 4
• For DSWPD, must take between 19:00-21:00, not at actual bedtime. 1, 2

Wrong Indication = Wasted Treatment

• Using melatonin for primary insomnia wastes time and delays effective treatment with FDA-approved hypnotics or CBT-I. 1, 3

Insufficient Treatment Duration

• Must continue for at least 28 days to assess efficacy in DSWPD. 1, 2
• Stopping too early may lead to false conclusion of treatment failure. 1

Safety Considerations

• No serious adverse reactions documented across age groups. 2, 3
• Common mild side effects include morning headache, morning sleepiness, and gastrointestinal upset. 2, 3
• Exercise caution in patients taking warfarin or with epilepsy due to potential interactions. 2, 3
• Choose reputable formulations (United States Pharmacopeial Convention Verified) for reliable dosing. 2

Practical Starting Algorithm

Step 1: Identify the condition

• Chronic insomnia → Do NOT use melatonin; use FDA-approved hypnotics or CBT-I 1, 3
• DSWPD or circadian rhythm disorder → Proceed to Step 2 1, 2

Step 2: Start 3-5 mg immediate-release melatonin

• Administer between 19:00-21:00 (or 1.5-2 hours before desired sleep time) 1, 2, 3
• Continue for minimum 28 days before assessing efficacy 1, 2

Step 3: If inadequate response after 28 days

• Can titrate upward in 3 mg increments, but do not exceed 10 mg due to receptor desensitization risk 2, 3