Jet lag is a complex condition which occurs when flying long distances. The main, but not the only cause, is crossing time zones, which causes circadian dysrhythmia. Other causes are dehydration and problems from pressurized cabins (pressure equivalent to 8,000 feet), lack of fresh air, lack of exercise and loss of quality sleep.

One tablet of No-Jet-Lag should be taken at the time of each take-off, another every two hours in flight, and another after each landing (including at intermediate stops). During long flights, the two-hour intervals may be extended if the user is sleeping.