Doctors call for licensing of jet lag treatment

A proven treatment for jet lag that is banned in Britain should be made available to long-distance air travellers by funding the necessary safety tests from the public purse, doctors will say today.

A proven treatment for jet lag that is banned in Britain should be made available to long-distance air travellers by funding the necessary safety tests from the public purse, doctors will say today.

The hormone melatonin, despite being illegal, is widely used to prevent the fatigue, sleeplessness, loss of concentration and irritability associated with long-haul air travel. It is found naturally in the body and helps to control normal body rhythms, which are disturbed when flying across time zones.

Although officially banned in Britain, melatonin can be obtained illegally in some health food shops and on the internet. In some countries, including America, Thailand and Singapore, it is sold legally as a dietary supplement in health food stores and pharmacies.

In Europe, Australia and many other countries, melatonin is classed as a medicine and requires a licence. But no commercial organisation is prepared to invest in the tests required to obtain a licence.

Writing in the British Medical Journal, Andrew Herxheimer of the UK Cochrane Centre, and Jim Waterhouse of John Moores University, Liverpool, call for the anomaly to be ended. They want melatonin made available to all who need it. They say its absence from the market is damaging to the interests of the travelling public, governments, the armed forces and big organisations whose staff fly frequently.

Jet lag occurs when the body clock is out of phase with the day/night cycle of the time zone in which the traveller has arrived. The body clock, which controls the secretion of melatonin by the pineal gland, is turned off by light. By taking supplements of melatonin, travellers can speed up adaptation to the new time zone.

Other non-drug methods rely on light. After a westward flight from Britain to America, travellers are advised to stay awake until the sun sets (even though at home the time might be 4am).

After an eastward flight from Britain to Singapore, the advice is to be awake but avoid bright light in the morning and to be outdoors as much as possible in the afternoon.

A review of research into melatonin found 10trials that compared the hormone to placebo in long-distance travellers. In eight of the 10 studies, the hormone was shown to reduce jet lag, probably by encouraging sleep and shifting the body clock phase.

Researchers say it could help as many as one in every two travellers, though some will never need it. Between 2mg and 5mg of melatonin taken at bedtime after arrival is effective and may be worth repeating for up to four days.

Side-effects are few but studies have not looked for them systematically, so some adverse reactions might have been missed. People who have epilepsy and those taking anti-coagulant drugs such as warfarin should avoid melatonin.

The authors say no drug company is interested in paying for the tests to license melatonin as a drug because it could not be patented. A public body should step in. "If use of the drug is in the public interest then public funds should be used to get it properly tested and licensed," they say.

Melatonin is also the hormone implicated in disruption to the body clock caused by shift work and the dark winter days that bring on Seasonal Affective Disorder. A short course of the hormonal supplement may help shift workers to adjust in the same way it helps travellers with jet lag.