A new threat to the Beijing Olympics has emerged in the shape of two new undetectable drugs that could boost the performance of endurance athletes by a medal-winning margin.
Scientists warned that the pills, which mimic the physiological effects of exercise, are already available and can be easily synthesised, but there is no existing test to reveal their presence. UK Sport, the government-funded agency, said yesterday's revelation was a "cause for concern" and that the World Anti-Doping Agency had been informed.
The drugs have so far only been tested on mice, but with remarkable results. The animals became mini-marathon runners, with powers of stamina that allowed them to far outrun untreated mice.
One drug, AICAR, increased running time by 44 per cent in "sedentary" mice which had done no exercise at all, and has already been dubbed the "couch potato's dream". The drug works by short-circuiting the signals normally triggered by exercise that tell cells to burn fat, lower blood sugar and suppress inflammation, thus releasing more energy.
Professor Ronald Evans, who led the research at the Salk Institute in La Jolla, California, said: "This is a drug that is like pharmacological exercise. We were blown away. After four weeks of receiving the drug the mice were behaving as if they had been exercised."
AICAR is not licensed for human use and is only available in Britain for research into metabolic conditions such as diabetes. Laurence Eade, the managing director of Tocris Biosciences in Bristol, which supplies AICAR at £48 for 50mgs to scientific institutions, said: "We would not send it to a university sports centre, only to the department of biochemistry. An aspiring athlete could not get it without a great deal of effort."
A second drug tested by the US researchers, called GW1516, had an even bigger impact when combined with exercise. Treated mice ran for 77 per cent longer and covered a 68 per cent greater distance than animals that exercised without the drug. GW1516 has a simple chemical structure that would be easy to synthesise, say researchers.
The aim of the research is to improve the efficiency of exercise and help those who, through frailty or ill-health, do not get enough. Professor Evans said: "If you don't like exercise, you love the idea of getting the benefits from a pill [with AICAR]. If you do like exercise, you like the idea of getting more bang for your buck [with GW1516]."
But there is a danger that the drugs could be abused by athletes. The sports world has long been aware of his laboratory's work and it was likely that athletes would seek their own sources of the drug, if they hadn't already, he said. "Drugs that improve health are not only going to be used by people who have medical problems. They may also be used by people who are healthy or by athletes who want an edge," he said.
Working with the World Anti-Doping Agency, the researchers have developed a test to detect the two compounds, but it is unlikely it will be ready for the opening of the Olympics in Beijing in two weeks' time.
A spokeswoman for the British Olympic Association said the association's chief medical officer in Beijing, Dr Ian McCurdie, was aware of the drugs.