What is the recommended daily dose of melatonin for a general adult population?

Recommended Melatonin Dose Per Day

The American Academy of Sleep Medicine explicitly recommends against using melatonin for chronic insomnia in adults, as the evidence shows no clinically significant benefit at the studied 2 mg dose; however, for circadian rhythm disorders like delayed sleep-wake phase disorder (DSWPD), use 5 mg administered between 19:00-21:00 (7-9 PM), 1.5-2 hours before desired sleep onset, for a minimum of 28 days. 1, 2

Clinical Context Determines Appropriate Use

For Chronic Insomnia: NOT Recommended

• Do not use melatonin for chronic insomnia. The 2017 American Academy of Sleep Medicine guideline found only a 9-minute reduction in sleep latency with 2 mg doses compared to placebo—below the threshold for clinical significance. 3, 1, 2
• The quality of evidence was very low due to publication bias, heterogeneity, and imprecision, with benefits approximately equal to harms. 3
• Meta-analysis showed no clinically meaningful improvements in total sleep time, wake after sleep onset, or sleep quality at this dose. 3, 1
• Consider FDA-approved hypnotics or cognitive behavioral therapy for insomnia (CBT-I) instead. 1

For Circadian Rhythm Disorders (DSWPD): 5 mg Dose

• Use 5 mg melatonin administered between 19:00-21:00 (7-9 PM), which is 1.5-2 hours before desired sleep onset, for a minimum of 28 days. 1, 2
• This timing is critical—administration at bedtime rather than 1-2 hours before is a common error that reduces efficacy. 1, 2
• This dose showed reduction in sleep latency by 38-44 minutes and increased total sleep time by 41-56 minutes. 1, 2
• This represents a weak recommendation based on low-quality evidence but applies to adults both with and without comorbid depression. 1

For Elderly Patients (≥55 Years) with Sleep Onset Delay

• The 2 mg dose showed approximately 19 minutes reduction in sleep latency in elderly patients (>55 years) compared to placebo. 2
• However, given the overall lack of clinically significant benefit for chronic insomnia, this population should still be evaluated for circadian rhythm disorders before initiating treatment. 3

For Jet Lag Prevention

• Melatonin 0.5-5 mg taken close to target bedtime (10 PM to midnight) at the destination is effective for flights crossing five or more time zones. 4
• People fall asleep faster and sleep better after 5 mg than 0.5 mg, though daily doses between 0.5-5 mg are similarly effective overall. 4
• Doses above 5 mg appear to be no more effective. 4
• The number needed to treat (NNT) is 2, with greater benefit for eastward flights and more time zones crossed. 4

Formulation Considerations

• Prolonged-release (sustained-release) formulations are preferred over immediate-release for maintaining sleep throughout the night and mimicking normal physiological circadian rhythm. 2
• The relative ineffectiveness of 2 mg slow-release melatonin for insomnia suggests that a short-lived higher peak concentration works better for circadian rhythm disorders. 4
• Over-the-counter preparations commonly contain 3 mg tablets. 5

Safety Profile and Adverse Events

• Melatonin has a good safety profile with minimal adverse effects at doses up to 5 mg. 6, 7
• The most frequently reported adverse events are daytime sleepiness (1.66%), headache (0.74%), dizziness (0.74%), and other sleep-related effects (0.74%). 6
• Higher doses (≥10 mg) appear to increase the risk of adverse events such as drowsiness, headache, and dizziness but do not cause a detectable increase in serious adverse events or withdrawals due to adverse events. 7
• Most adverse events resolve spontaneously within a few days or immediately upon withdrawal of treatment. 6
• No life-threatening or major clinically significant adverse events have been identified in systematic reviews. 6

Critical Pitfalls to Avoid

• Do not increase dose beyond 5 mg—escalation provides no definitive additional benefits. 2, 4
• Timing matters more than dose: If melatonin is taken at the wrong time, early in the day, it is liable to cause sleepiness and delay adaptation to local time. 4
• Do not use in patients with epilepsy or those taking warfarin, as case reports suggest potential harm. 4
• Do not expect benefit for chronic insomnia—this is the most common misuse of melatonin in clinical practice. 3, 1, 2

Duration and Monitoring

• Trial duration: Minimum 28 days (3-4 weeks) to assess efficacy before considering dose adjustment or discontinuation. 1, 2
• No specific dose adjustments are provided for renal or hepatic impairment, as melatonin has a favorable safety profile. 2
• Monitor for additive sedation if patients are on multiple CNS-active medications. 2
• No significant drug-drug interactions exist with common medications including doxepin, propranolol, or SSRIs. 2