One of the hassles about long distance air travel is jet lag. Jet lag occurs when the body’s internal rhythms no longer work in synchrony.
The day and night cycle become disturbed and the individual often requires several days to get back into his/her normal rhythm. There is evidence that melatonin, a hormone released from the pineal gland, is important when it comes to regulating many body rhythms and the sleep-wake cycle. For decades, melatonin has been sold in health stores as an aid for sleep and help recovery from jet lag.
Millions of pills of melatonin are bought by consumers to treat jet lag, but is melatonin effective?
Cochrane reviews recently looked at 10 randomized clinical trials in which melatonin were used by airline personnel, military employees and other regular airline passengers. Melatonin was compared to a sugar pill. The outcome measures looked at subjective well being daytime tiredness, onset, quality of sleep, psychological functioning, duration of return to normal, or indicators of circadian rhythms.
The studies found that melatonin was quite effective when taken close to the target bedtime at the destination, decreased jet lag from flights crossing 5 or more time zones. Daily doses of melatonin between 0.5 and 5mg were both equally effective, except that people started to fall asleep a lot faster when using the higher dose. Doses above 5mg appeared to be no more effective than the lower doses of melatonin.
A slow-release preparation of 2 mg melatonin also worked well at inducing sleep. Some studies indicated that this formulation may be of more benefit when greater than 4-5 time zones are crossed.
The studies revealed that timing of the melatonin dose was important. If the melatonin was taken at the wrong time or very early in the day, it was likely to cause sleepiness and delay adaptation to local time. The incidence of other side effects was low. A number of case reports have also suggested that individuals with epilepsy and patients taking warfarin (blood thinner) might come to harm from melatonin.
Conclusion
Melatonin is quite effective in preventing or reducing jet lag, and for short-term use appears to be safe. It may be a choice for jet lag treatment for travelers flying across five or more time zones, particularly in an easterly direction, and especially if they have experienced jet lag on previous journeys. Despite these positive reports, there are a lot of anecdotal reports that melatonin often fails to work. The reason(s) for these discrepancies are not well understood, but more likely than not, are probably related to fake or counterfeit products.
http://www.cochrane.org/reviews/en/ab001520.html