Key Takeaway
Melatonin is remarkably effective for preventing or reducing jet lag, particularly when crossing 5 or more time zones and traveling eastward.
Summary
This Cochrane systematic review evaluated all available randomized controlled trials on melatonin for jet lag prevention and treatment. It remains a foundational reference for melatonin's use in circadian disruption.
The review concluded that melatonin is remarkably effective, with the majority of trials showing significant benefit. The effect is greater for eastward travel and when crossing more time zones.
Methods
- Cochrane systematic review methodology
- 10 randomized controlled trials included
- Participants: airline staff, military personnel, and general travelers
- Doses ranged from 0.5mg to 5mg
- Various timing protocols evaluated
Key Results
- 8 of 10 trials showed significant jet lag reduction
- Most effective crossing 5+ time zones
- Greater benefit for eastward travel
- 0.5-5mg doses similarly effective
- Optimal timing: close to destination bedtime
- Daily doses more effective than single doses
- NNT (number needed to treat) of approximately 2
Limitations
- Heterogeneous outcome measures
- Variable definitions of jet lag
- Most participants were healthy adults
- Limited data on optimal dose
- Few studies directly compared timing protocols