On the African plains, the most aggressive lion leads his pride. As with lions, so with men. Testosterone isn’t needed just for building the typical male muscular physique that enables a lion or athlete to dominate other males, win a mate and battle with would-be successors.

It also affects the psyche and nourishes the determination, aggression and sexual vigour (whether in the jungle, veldt, playing field or boardroom) that provides the necessary motivation to win, and to hold on to winnings.

Testosterone has a moderately rapid effect on sexual prowess. I once had a patient who was not only impotent but quite content to be impotent, except for two fortnights a year. These were the times that he shared a holiday with a girlfriend, whom he had dated in his virile youth. He attended my surgery the week before his holiday, had a testosterone injection and was a lothario throughout his romantic tryst.

Do testosterone supplements work fast enough to help athletes win races? Certainly the multiple actions of testosterone have prompted Professor Allan Mazur of Syracuse University to query the value of testosterone when taken immediately before an athletic performance.

Professor Mazur wonders whether the hormone could have been key to explaining the contrast between Floyd Landis, the cyclist’s, lacklustre performance on the penultimate day of the Tour de France and his storming victory the next day. He subsequently tested positive for synthetic testosterone in his urine but denies that he took the hormone.

Success on the sports field is a combination of physical strength, skill and determination. A schoolmaster told me recently that it was difficult, probably impossible, to assess a young boy’s true athletic ability until after puberty and the effect of testosterone could be seen on his muscular development and determination to succeed.

A pre-adolescent boy might show outstanding co-ordination and skill, but it was only after the testosterone flowed, naturally of course, that a final appreciation could be made of his muscular power and mental stamina — and hence the likelihood that he would triumph and become a good athlete.

If Floyd Landis had taken too big a dose of testosterone before the race, he might well have suffered a severe headache, depression and disturbed sleep. However, corrupt athletic trainers are now also expert pharmacologists and their knowledge has spread throughout the sporting world so most athletes are conversant with the effect of drugs, even if they don’t use them. The fear is that international competitions will continue to lose public support if they become competitions to select shrewd pharmacologists, rather than the fittest athletes.

Although doctors may not be sure about the optimal time for an athlete to apply a testosterone patch, have a jab or even use a sustained release system through the inside of the cheek to win a race, it is common knowledge around the tracks.

Doctors, however, do know that the plasma half-life of natural testosterone, before it is chemically modified, can range from ten to 100 minutes. This demonstrates the need to find preparations or methods of delivery that, when used clinically, will result in slower absorption and more prolonged action.

It also reveals that there are rapidly absorbed forms of testosterone that might help an athlete to win a race by changing the psyche if not the muscles.

Testosterone needs to be used with care in people with heart disease, kidney or liver problems. It may make epilepsy, migraine or diabetes worse and it may lead to some cancers. Its continued use may cause aggressive behaviour, depression and sleep apnoea.

Paradoxically, in the long term it may even reduce potency and fertility.