What dose of melatonin (melatonin) is considered harmful?

Melatonin Safety and Dosage Guidelines

Melatonin doses above 5 mg are generally considered potentially harmful for most adults, while lower doses of 1-5 mg are typically safe and effective for sleep disorders. 1

Safe Dosage Ranges by Population

Melatonin dosing should follow these evidence-based guidelines:

• Adults: 1-5 mg approximately 1-2 hours before bedtime 1
• Adults with DSWPD: 5 mg taken between 7:00-9:00 PM 1
• Elderly patients: Start with lower doses (1-2 mg) and titrate as needed 1
• Children with DSWPD and no comorbidities: 0.15 mg/kg taken 1.5-2 hours before habitual bedtime 2, 1
• Children with DSWPD and psychiatric comorbidities: 3-5 mg (weight-based) taken at 18:00 or 19:00 1
• Patients with REM Sleep Behavior Disorder: Starting with 3 mg at bedtime, which may be titrated up to 15 mg if needed 1

Safety Profile and Adverse Effects

Melatonin has a generally favorable safety profile compared to other sleep medications:

• Common mild adverse effects (occurring at rates <2%): daytime sleepiness (1.66%), headache (0.74%), dizziness (0.74%), and hypothermia (0.62%) 3
• Less common adverse effects: agitation, fatigue, mood swings, nightmares, skin irritation, and palpitations 3
• Most adverse effects resolve spontaneously within days or immediately upon discontinuation 3
• High-dose melatonin (≥10 mg) appears to increase the risk of mild adverse effects such as drowsiness, headache, and dizziness, but does not increase serious adverse events or withdrawal rates 4

Special Considerations

For Children

• Key concerns: Potential effects on growth hormone regulation and possible impacts on reproductive function/development 1
• Monitoring needed: Daytime drowsiness, headache, dizziness, changes in mood, and potential hormonal effects with long-term use 1

For Elderly

• Start with lower doses (1-2 mg) due to potentially increased sensitivity 1
• May be particularly beneficial for this population, with evidence suggesting improved sleep latency 2

For Specific Conditions

• Patients with epilepsy, hepatic impairment, or those taking warfarin: Require special caution due to potential interactions 1
• Patients on multiple medications: Consider potential drug interactions with melatonin 1

Administration Guidelines

• Administer on an empty stomach to maximize effectiveness 1
• Take 1-2 hours before bedtime for optimal effect 1
• Typical target bedtime: 10 pm to midnight 1
• For DSWPD in adults: 5 mg dose timed between 19:00-21:00 2

Long-term Safety Considerations

While melatonin is generally considered safe, there are limitations to current evidence:

• Most studies are short-term (4 weeks or less) 3
• Limited data from long-term randomized controlled trials restricts conclusions about continuous therapy over extended periods 3
• No life-threatening adverse effects have been identified in studies 3
• Regular monitoring for efficacy and side effects is recommended 1
• Periodic attempts to discontinue treatment should be made to assess continued need 1

Efficacy Considerations

Melatonin shows modest benefits for sleep disorders:

• For insomnia: Mean reduction in sleep latency of 9 minutes compared to placebo 1
• Small improvement in quality of sleep 1
• More effective for sleep onset than sleep maintenance issues 2
• Higher doses (5 mg) may significantly increase sleep efficiency during both biological day and night, mainly by increasing Stage 2 non-REM sleep 5

Melatonin should be part of a broader approach to improving sleep, including non-pharmacological interventions such as consistent sleep schedules, optimizing the sleep environment, and reducing evening blue light exposure 1.