Is melatonin (melatonin) effective for regulating sleep?

Melatonin's Effectiveness for Sleep Regulation

Melatonin shows mixed effectiveness for sleep regulation, with stronger evidence supporting its use for circadian rhythm disorders than for general insomnia in adults. 1, 2

Effectiveness in Different Populations

Children with Autism Spectrum Disorder (ASD)

• Melatonin is effective in improving sleep in children with ASD, particularly for sleep latency (time to fall asleep), sleep duration, and sleep onset time 1
• Multiple randomized controlled trials have shown significant improvements in sleep parameters when melatonin is used in children with ASD who have not responded to behavioral interventions 1
• Specific improvements include:
  • Reduction in sleep latency by 28-42 minutes 1
  • Increase in total sleep time by approximately 21 minutes 1
  • Improved sleep onset time by 42 minutes 1

Adults with Insomnia

• The American Academy of Sleep Medicine suggests against using melatonin for treating sleep onset or maintenance insomnia in adults (weak recommendation) 1
• Meta-analyses of studies using 2mg doses in older adults (>55 years) showed no clinically significant improvement in sleep quality 1
• Evidence for melatonin's efficacy in improving sleep onset, maintenance, or quality in the general adult population is minimal and weakly negative 1

Mechanism of Action

• Melatonin is the major sleep-promoting hormone under circadian control, with levels normally peaking just before sleep initiation 1
• It acts through two high-affinity G protein-coupled receptors (MT1 and MT2) involved in maintaining circadian rhythms underlying the normal sleep-wake cycle 3
• Melatonin can influence sleep through both:
  • Phase-shifting effects on circadian rhythms 4
  • Possible direct soporific (sleep-inducing) effects 5

Optimal Use Considerations

Dosing

• Lower doses (0.3-1.0mg) are recommended initially, as higher doses may cause receptor desensitization 2
• For circadian rhythm effects, melatonin should be taken 1.5-2 hours before desired bedtime 2
• In children with ASD, doses of 1-4mg have shown effectiveness 1

Specific Applications

• Most effective for circadian rhythm sleep-wake disorders, including:
  • Delayed Sleep-Wake Phase Disorder 3
  • Non-24-Hour Sleep-Wake Rhythm Disorder (especially in blind individuals) 3
  • Jet lag and shift work adjustment 4, 6

Safety and Limitations

• Melatonin is marketed as a dietary supplement in the US, not as a regulated medication 7, 5
• Safety concerns include:
  • Potential impaired glucose tolerance 2
  • Possible interactions with warfarin and photosensitizing medications 2
  • Limited data on long-term safety and efficacy 5, 8
• Quality control issues exist with commercially available preparations 8

Clinical Decision Algorithm

1. For children with ASD and sleep problems:

   • First try behavioral interventions
   • If unsuccessful, consider melatonin (1-4mg) 30-40 minutes before bedtime 1

2. For adults with circadian rhythm disorders:

   • Melatonin can be effective, particularly for jet lag and shift work 4, 6
   • Use lower doses (0.3-1mg) initially 2, 8

3. For adults with general insomnia:

   • Consider other interventions first, as evidence does not strongly support melatonin use 1
   • If using melatonin, choose USP Verified formulations for reliable dosing and purity 2

4. For all patients:

   • Document concurrent medications to review for potential interactions 2
   • Periodically reassess effectiveness and continued need 2