What is the recommended dosage and administration guidelines for an adult patient with insomnia considering taking a melatonin (N-acetyl-5-methoxytryptamine) 3 mg tablet?

Melatonin 3 mg for Insomnia: Not Recommended

The American Academy of Sleep Medicine explicitly recommends against using melatonin for the treatment of chronic insomnia in adults, as clinical trials demonstrate no clinically meaningful benefit for sleep onset or maintenance insomnia. 1

Evidence Against Melatonin for Chronic Insomnia

The 2017 AASM clinical practice guideline provides a weak recommendation against melatonin based on trials using 2 mg doses, showing: 1

• Sleep latency reduction: Only 9 minutes compared to placebo (95% CI: 2-15 minutes) 1
• Total sleep time: Not significantly improved 1
• Quality of sleep: Only small subjective improvement 1
• Quality of evidence: Very low 2

The clinical significance of a 9-minute reduction in sleep latency is negligible and does not justify routine use for insomnia. 2

Why the 3 mg Dose Is Problematic

While your question asks about 3 mg specifically, the evidence base evaluated 2 mg doses and found them ineffective. 1 Higher doses (3 mg) have not been shown to provide superior efficacy for chronic insomnia and may increase adverse effects such as drowsiness, headache, and dizziness. 3

The AASM guideline concluded that benefits are approximately equal to harms, making melatonin an inappropriate choice for chronic insomnia treatment. 2

When Melatonin IS Appropriate

Melatonin has a legitimate role in circadian rhythm disorders, not insomnia: 2

• Delayed Sleep-Wake Phase Disorder (DSWPD): Use 5 mg administered between 19:00-21:00 (1.5-2 hours before desired sleep onset) for at least 28 days 2, 4
• This timing is critical—administration at bedtime is ineffective 2, 4
• Evidence shows 38-44 minute reduction in sleep latency and 41-56 minute increase in total sleep time for DSWPD 2

Recommended Alternatives for Chronic Insomnia

Instead of melatonin 3 mg, consider FDA-approved options with demonstrated efficacy: 1

For sleep onset insomnia:

• Zolpidem 10 mg (29 min improvement in total sleep time, 25 min reduction in wake after sleep onset) 1
• Zaleplon 10 mg 1
• Triazolam 0.25 mg 1
• Ramelteon 8 mg (melatonin receptor agonist, not melatonin itself) 1

For sleep maintenance insomnia:

• Eszopiclone 2-3 mg 1
• Doxepin 3-6 mg 1
• Suvorexant 10-20 mg 1

Non-pharmacologic first-line:

• Cognitive Behavioral Therapy for Insomnia (CBT-I) should be considered before pharmacotherapy 2

Common Pitfalls to Avoid

• Do not prescribe melatonin 3 mg for chronic insomnia simply because it is available over-the-counter or perceived as "natural"—the evidence does not support this use 1, 2
• Do not confuse melatonin with ramelteon (a melatonin receptor agonist), which IS recommended for sleep onset insomnia 1
• Do not administer melatonin at bedtime if using it for circadian disorders—timing 1.5-2 hours before desired sleep is essential 2, 4
• The fact that melatonin is not FDA-approved creates ambiguity in dosing and timing, unlike prescription hypnotics with established protocols 4

Safety Considerations

While melatonin appears to have a favorable safety profile even at higher doses (≥10 mg), with mild adverse effects including drowsiness, headache, and dizziness, this does not justify its use for an indication where it lacks efficacy. 3 The absence of severe toxicity does not equate to clinical benefit for insomnia. 5, 3