Melatonin is released by the pineal at sunset. Its release is continuous throughout the night. It is shut off in the AM by bright light. Its release may be phase shifted. Melatonin in the morning (0.5-1 mg are sufficient) causes phase delays, and in the afternoon causes phase advances. All of the circadian disorders which have been successfully treated with appropriately timed exposure to bright light (intensity equivalent to outdoor light) can be treated with appropriately scheduled melatonin administration.
It uses include:

1. "Jet Lag"
2. Shift workers
3. In the elderly, where the usual temporal relationship between body temperature and sleep is altered. Evening bright light exposure is beneficial in alleviating sleep maintenance insomnia. Not clear if these results may be generalized at this time to demented patients.
4. Advanced and delayed sleep insomnia: Exposure to light early is corrective for phase delays and late light exposure for phase advances.

There are no standards for the commercial production and sale of melatonin. In general, synthetic melatonin is recommended as pineal extracts may potentially contain transmissible diseases. As with all Dietary Supplements, consumers should only purchase those with USP certification, to ensure product purity and accuracy in labeling.

An example of a jet lab protocol: If you are going 6 hours (time zones) east, it will in general take a day to adjust for each hour of difference. A simple protocol would be:

• 6th Day before departure: take 1 mg of melatonin 1 hr before sunset (where you live)
• 5th Day before departure: take 1 mg of melatonin 2 hrs before sunset
• 4th Day before departure: take 1 mg of melatonin 3 hrs before sunset
• 3rd Day before departure: take 1/2 mg of melatonin 4 hours before sunset, and another 1/2 mg 2 hrs before sunset.
• 2nd Day before departure: take 1/2 mg of melatonin 5 hours before sunset, and another 1 mg 3 hrs before sunset.
• Day before departure: take 1 mg of melatonin 6 hours before sunset, and another 1 mg 3 hrs before sunset.

Day of arrival, make sure to get early morning sunshine for at least an hour. The earlier and brighter, the better.

When travelling to countries that are approximately 12 time zones to the east or west of your current time zone, there is no way to know without testing, wether you would be best off trying to advance or retard your circadian melatonin cycle. In this case, good sleep hygeine would be appropriate, including awaking every morning shortly after sunrise and spending the first hour of each day in a bright light environment, if possible. In addition, taking 1mg of melatonin at sunset will ensure that your melatonin goes up as it would during a normal circadian cycle. It would make sense to continue this therapy for 3-5 days, depending on your response, as by 6-7 days, most people will have acclimated without any intervention (generally humans are capable of shifting their circadian rhythm forward or backward by up to 1-2 time zones a day).