Woozy. Irritable. Unable to concentrate. Sweaty. Prickly. Disoriented. Jittery. Tired, but not sleepy.

There is no doubt that flying across time zones has an impact on the human body and you need to be well rested to be productive. But the effect of jet lag varies from trip to trip or person to person. Frequently suggested tactics such as avoiding naps, taking more daytime walks, or avoiding caffeine do not always work. As a result, most frequent travellers are on the lookout for a wonder drug that can mitigate the effect of jet lag.

Unfortunately, a single wonder drug does not exist yet -- but there is an increasingly robust selection of remedies, all of which should be taken under the advisement, prescription or supervision of a physician.

Promoting wakefulness
While most pills or medications used to battle jet lag help travellers sleep better, the newest prescription pills do the opposite: they help travellers stay awake and alert. Nuvigil (generic name: armodafinil) and Provigil (modafinil) are classified as “wakefulness-promoting agents” that treat the daytime sleepiness associated with jet lag.

Technically, these drugs are made to help people who suffer from the sleepiness that comes from night shift work, or as a result of maladies such as narcolepsy or sleep apnea. But unofficially, doctors can prescribe these drugs “off label” to patients hoping to ward off the effects of jet lag. Cephalon, the maker of Nuvigil, tried twice to get the drug officially approved to treat jet lag by the US Food and Drug Administration (FDA), the federal agency that regulates pharmaceutical companies. Cephalon even went so far as to conduct clinical trials among adults flying from the US east coast to Paris to show how well it kept jet-lagged travellers alert. However, the FDA turned the company down last December, questioning the data used to seek approval.

“I rarely prescribe it, but it does work for the few people who have asked for it -- those who need to be awake and alert when they arrive,” said physician Alla Kirsch, the medical director of Travel Clinics of America, a network of travel medicine specialists. “Doctors who don’t specialize in travel medicine might not be very familiar with it, but it is the subject of much discussion among those who do.”

Sleep aids
Physicians and travellers are likely to be more familiar with drugs that improve the ability to sleep enroute or upon arrival. It is thought that adjusting sleep patterns to the destination as quickly as possible helps reduce the effects of jet lag.

So-called “hypnotic” drugs such as Ambien (zolpidem), Lunesta (Eszopiclone) or Sonata (zaleplon) are perhaps the best-known prescription sleeping aids used by frequent travellers. They are fast acting (put you to sleep quickly) but short acting (do not keep you down for long, usually three to five hours). Since they are quickly metabolized and eliminated from the body, they rarely result in any “hangover effect”. (Note: these drugs work faster if not taken immediately after a meal -- consider this if you plan to take them during a long flight that includes meal service.)

To get better sleep in flight or upon arrival, or to worry less about sleep loss, some travellers turn to drugs normally prescribed to treat anxiety, such as Xanax (alprazolam) or Valium (diazepam). “While these drugs might help with sleep, they actually provide a sense of calmness, not necessarily sedation. Travellers should also be wary of the longer-acting effects of these drugs,” said Dr Kirsch.

One of the most popular non-prescription drugs used by frequent travellers is
Diphenhydramine, the active ingredient in products such as Benadryl, Sominex, Advil PM or Tylenol PM. It is used to treat mild allergies, motion sickness and insomnia. It is relatively short acting, but some travellers do report a hangover effect.

Some travellers rely on alcohol to help them relax and get to sleep on the plane. Dr Kirsch warns that those who take drugs to help them sleep during flight should be sure to avoid alcohol, drink plenty of water and stretch and move around as much possible before and after naps. “Sitting or lying still for hours on a plane can lead to blood clots,” she said.

Another popular over-the-counter sleep aid widely used to improve sleep and battle jet lag is a synthetic form of melatonin, a hormone secreted by the body’s pineal gland each day as the sun sets. Travellers can take one to three milligrams of melatonin during a long flight and/or at their destination to help fall asleep and adjust their circadian rhythms.

“Although the proper types and timing of meals helps your body produce melatonin naturally and at precisely correct times, the addition of melatonin pills can enhance this effect,” wrote Bill Ashton of StopJetLag.com, a California company that prepares detailed pre-trip eating/drinking/sleeping schedules for travellers embarking on trips across time zones. “The timing for using melatonin is based on both your personal profile and the flight times in your itinerary.”

Low doses of melatonin can also help jet-lagged travellers who awaken in the middle of the night to fall back to sleep.

In the United States, melatonin is sold as a food supplement, not a drug or medication. Since certain forms of melatonin are derived from animal products, some countries, including the United Kingdom and Canada, have banned the sale of melatonin over fears of the transmission of viruses.

Other products
There are a wide variety of pills, potions and products designed to help travellers overcome the effects of jet lag without drugs. For example, the popular Jet Lag Formula (taken during long distance flights) contains a blend of 12 herbs that boost the immune system, offset dehydration and improve circulation. Bulldozer is a new airport-security-friendly 3-oz blend of B vitamins and fruit juices combined with melatonin, rose hips and valerian root -- all used by herbalists to help travellers cope with anxiety and insomnia. Then there is NightWave a portable, battery operated device that focuses the mind and regulates breathing using a soft blue light that pulsates on the bedroom or hotel room ceiling, hopefully lulling travellers into the time zone of their vacation or business trip.

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Chris McGinnis is the business travel columnist for BBC Travel.