Meanwhile, men who choose to take testosterone have only preliminary research to go on.

Many women body builders will take testosterone in order to be able to increase their muscle mass.

What other effects taking testosterone may have on athletes is the subject of heated debate.

After athletes stop taking testosterone, the body may take weeks to months to return to normal hormone levels.

The most striking results were in the men who took both growth hormone and testosterone.

But Kay could not see why a cyclist would take testosterone.

When people with cardiovascular disease take testosterone, their circulation improves.

In 2000 he admitted using illegal substances but denied taking testosterone.

Taking additional testosterone, as in anabolic steroids, will increase results.

The scientists saw no difference between the men who took testosterone and those who did not.