Melatonin Safety During Sleep
Melatonin is generally safe during sleep for most individuals when used at appropriate dosages, with only mild side effects reported in clinical studies. 1, 2
Safety Profile
Melatonin is widely available as a dietary supplement in the US 3 and is recommended by the American Academy of Sleep Medicine for various sleep disorders 1
Most common adverse events are mild and include:
- Daytime sleepiness (1.66%)
- Headache (0.74%)
- Dizziness (0.74%)
- Other sleep-related adverse events (0.74%)
- Hypothermia (0.62%) 2
Less common adverse events include agitation, fatigue, mood swings, nightmares, skin irritation, and palpitations 2
Most adverse events resolve spontaneously within days or immediately upon discontinuation 2
Dosing Considerations
The American Academy of Sleep Medicine recommends specific dosages based on patient populations:
- Children with DSWPD (Delayed Sleep-Wake Phase Disorder) without comorbidities: 0.15 mg/kg taken 1.5-2 hours before bedtime
- Children with DSWPD and psychiatric comorbidities: 3-5 mg (3 mg if <40 kg; 5 mg if >40 kg)
- Adults: 1-5 mg approximately 1-2 hours before bedtime 1
Special Populations and Considerations
Children
- Melatonin has shown efficacy for sleep problems in children with autism spectrum disorders and neurodevelopmental disabilities 4, 1
- Improves sleep duration, latency, and sleep onset time in children with Asperger syndrome 4
- Long-term safety data in children is limited, with potential concerns about effects on growth hormone regulation and reproductive development 1, 5
Adults
- Higher doses (≥10 mg) appear to have a good safety profile but may increase the risk of mild adverse events like drowsiness, headache, and dizziness 6
- No significant increase in serious adverse events or withdrawals due to adverse events in meta-analyses 6
Formulation Considerations
- Immediate-release formulations are recommended for sleep onset issues
- Sustained/prolonged-release formulations are recommended for sleep maintenance issues 1
Important Precautions
- Regular monitoring for efficacy and side effects is essential
- Periodic attempts to discontinue treatment to assess continued need
- Special caution needed for patients with:
- Epilepsy
- Hepatic impairment
- Those taking warfarin or multiple medications due to potential interactions 1
Quality Control Issues
- In the US, melatonin is classified as a dietary supplement with no regulatory oversight of manufacturing 7
- Actual melatonin concentration in marketed preparations varies widely between product labels and manufacturers 7
While melatonin is generally considered safe for short-term use, long-term safety data from high-quality randomized controlled trials is limited 2, 5, 7. Most studies have been of short duration (4 weeks or less), making it difficult to fully assess the safety of continuous melatonin therapy over extended periods 2.
Human studies: Melatonin for sleep disorders
| Population | Efficacy | Safety Concerns |
|---|---|---|
| General adults | Modest effect on sleep onset | Few mild-moderate adverse events |
| Children with neurodevelopmental disorders | Effective for sleep onset | Potential hormonal effects with long-term use |
| Elderly | May be beneficial at lower doses | Start with lower doses (1-2 mg) |
For optimal safety, use the lowest effective dose and consult with a healthcare provider before long-term use, especially for children and those with underlying medical conditions.