Melatonin is the hormone of darkness – a hormone from the pineal gland in the brain which controls the body’s internal clock. Melatonin levels increase when it is dark outside and this causes you to feel sleepy. A great deal of research is being undertaken on melatonin to clarify its role in treatment of jetlag.
In the United States, melatonin is available without a script and outsells vitamin C. In Australia, some melatonin is available on a script. In Dec 2002, a literature review found that 5mg of melatonin, taken at the target bedtime at the destination (10pm-midnight), for 2-5 days after arrival, decreased jetlag resulting from flights crossing five or more time zones. It seemed to work best in persons who were travelling eastward.
Melatonin is not recommended if you have epilepsy or take the drug warfarin. Science News 2008 published information about a food related ‘clock’ in the brain, that overrides the light based ‘clock’. A period of fasting for about 16 hours (e.g. no eating during the flight) and then eating as soon after landing seems to help travellers adjust to the new time zone more quickly than they would otherwise do.
… From “Travelling Well”. Available here for your kindle from Amazon