Can melatonin help with insomnia?

Melatonin for Insomnia

Melatonin has limited efficacy for primary insomnia in adults and should generally not be used for this indication, though it may be considered for specific circadian rhythm disorders and in pediatric populations with neurodevelopmental conditions. 1, 2

Evidence Quality and Recommendations

The American Academy of Sleep Medicine (AASM) suggests that clinicians NOT use melatonin as a treatment for sleep onset or sleep maintenance insomnia in adults (weak recommendation based on 2 mg doses). 1 This recommendation stems from very low quality evidence showing minimal clinical benefit—meta-analysis revealed no clinically significant improvement in sleep quality (SMD +0.21; CI: −0.36 to +0.77). 1

Key Efficacy Data for Primary Insomnia

The evidence for melatonin in primary insomnia is disappointing:

• Sleep latency reduction: Minimal and inconsistent effects, with some studies showing 28-minute improvements but failing to reach statistical significance (P = .10). 1
• Total sleep time: No clinically meaningful increase in most adult populations. 1
• Sleep efficiency: Objective polysomnography shows no significant improvement (+2.59%; CI: −3.25 to +8.43%). 1
• Sleep architecture: Melatonin does not improve deep slow-wave sleep (N3), REM sleep, or wake after sleep onset. 3

When Melatonin MAY Be Appropriate

Circadian Rhythm Disorders (Not Primary Insomnia)

For Delayed Sleep-Wake Phase Disorder (DSWPD) specifically, melatonin shows better evidence:

• Adults: 5 mg taken between 19:00-21:00 for 28 days. 2
• Children without comorbidities: 0.15 mg/kg taken 1.5-2.0 hours before habitual bedtime for at least 6 nights. 2
• Children with psychiatric comorbidities/autism: 3 mg if <40 kg or 5 mg if >40 kg, administered at 18:00-19:00 for 4 weeks. 2

Pediatric Populations with Neurodevelopmental Disorders

Melatonin is effective for children with autism spectrum disorders (ASD), improving sleep duration, latency, night wakings, and bedtime resistance. 1 Studies show:

• Sleep latency improved from 42.9 to 21.6 minutes (P < .001). 1
• Total sleep duration increased by 2.6 hours (P < .001). 1
• Dosing: 1-4 mg taken 30-40 minutes before bedtime. 1
• Safety profile is excellent with no serious adverse reactions documented. 2

Dosing Considerations When Used

If melatonin is prescribed despite limited evidence for primary insomnia:

• Start with 3 mg immediate-release (not slow-release, which is less effective for sleep onset). 2, 3
• Lower doses (0.3-1.0 mg) may be more effective than higher doses due to receptor desensitization with doses >10 mg. 2, 3
• Timing: 1.5-2 hours before desired bedtime for circadian effects. 2, 3
• Maximum dose: Typically 12-15 mg, though higher doses increase morning grogginess without added benefit. 2

Critical Safety Warnings

• Caution with warfarin: Case reports suggest potential interactions. 2, 3
• Caution in epilepsy: Limited case reports of concerns. 2, 3
• Impaired glucose tolerance: Documented in healthy women after acute administration. 3
• Quality control: Choose United States Pharmacopeial Convention Verified formulations for reliable dosing. 2, 3, 4

Clinical Algorithm

1. Confirm diagnosis: Is this primary insomnia or a circadian rhythm disorder? Melatonin is NOT recommended for primary insomnia. 1

2. If circadian rhythm disorder (DSWPD): Use weight-based dosing in children (0.15 mg/kg) or 5 mg in adults, timed 1.5-2 hours before desired sleep time. 2

3. If pediatric ASD with sleep problems: Use 1-4 mg taken 30-40 minutes before bedtime. 1

4. If elderly (>55 years) with primary insomnia: Consider 2 mg prolonged-release, though evidence is low quality and AASM recommends against routine use. 1, 2

5. Screen for contraindications: Document warfarin use, epilepsy, and photosensitizing medications before prescribing. 3

Important Caveats

The widespread perception of melatonin as a benign sleep aid does not align with the evidence for primary insomnia. 1 While side effects are generally mild (morning headache, sleepiness, GI upset), the lack of efficacy for sleep maintenance and architecture means patients may continue poor sleep despite subjective reports of "better sleep." 3, 5

Melatonin does NOT preserve normal sleep architecture—it lacks improvement in deep sleep stages that are crucial for restorative sleep. 3 This distinguishes it from true hypnotics and limits its utility in primary insomnia.

Long-term safety data remains limited, warranting periodic reassessment of continued use. 3, 6