Is melatonin safe to use?

Melatonin Safety Profile

Melatonin has a favorable safety profile compared to other sleep medications, with few immediate side effects except drowsiness, no short-term usage restrictions, and no evidence of withdrawal symptoms or rebound insomnia. 1

General Safety Considerations

Melatonin demonstrates a generally good safety profile with the following characteristics:

• Most frequently reported adverse events are mild and include:

  • Daytime sleepiness (1.66%)
  • Headache (0.74%)
  • Other sleep-related adverse events (0.74%)
  • Dizziness (0.74%)
  • Hypothermia (0.62%) 2

• Serious adverse events are rare, and most adverse events resolve spontaneously within days or immediately upon discontinuation 2

• Meta-analysis of high-dose melatonin (≥10 mg) showed no significant increase in serious adverse events or withdrawals, though it did slightly increase the risk of minor adverse effects like drowsiness, headache, and dizziness 3

Efficacy and Appropriate Use

Melatonin has modest effects on sleep parameters:

• Reduces sleep latency by approximately 9 minutes compared to placebo
• Provides small improvements in sleep quality 1
• More effective for sleep onset than sleep maintenance issues 4

Dosing Recommendations

Optimal dosing varies by population:

• Adults: 1-5 mg taken 1-2 hours before bedtime
• Elderly patients: Start with lower doses (1-2 mg) and titrate as needed
• Children with neurodevelopmental disorders:
  • 38% respond to low doses (2.5-3 mg)
  • 31% respond to medium doses (5-6 mg)
  • Only 9% require high doses (9-10 mg) 5

Special Populations and Precautions

Exercise caution in the following populations:

• Patients taking warfarin
• Patients with epilepsy
• Patients with hepatic impairment 1

For children with neurodevelopmental disorders:

• Monitor for potential effects on growth hormone regulation
• Consider possible impacts on reproductive function/development
• Consult with a pediatric sleep specialist rather than self-administering 1

Quality Control Concerns

An important caveat with melatonin use in the US:

• Melatonin is classified as a dietary supplement in the US with no FDA oversight
• Significant variation exists between product labels and actual melatonin content
• Hospital formulary products are preferred over patient's own supply 1, 6

Long-term Use Considerations

While short-term safety is well-established, long-term data is limited:

• Low to moderate doses (≤5-6 mg daily) appear safe for long-term use 6
• Regular monitoring for efficacy and side effects is recommended
• Periodic attempts to discontinue treatment should be made to assess continued need 1
• Long-term effects have been insufficiently studied and warrant additional investigation 6

Clinical Recommendation

For patients requiring sleep support, melatonin represents a safer alternative to many prescription sleep medications, particularly for addressing sleep onset difficulties. Start with the lowest effective dose (1-2 mg for adults), administer 1-2 hours before bedtime, and monitor for effectiveness and side effects. For long-term use, periodically reassess the need for continued therapy.