A chemical found in the possession of a University of Texas football player in October is often used to mask the results of steroid tests, doctors and NCAA officials say.

The chemical, epitestosterone, made by the Sigma Chemical Company, is reportedly finding its way into locker rooms where some athletes use it to beat steroid detection tests.Alan Luther, a reserve lineman for the Longhorns, was charged with possession of a controlled substance after police found a small vial labeled "epitestosterone" in his car, the Austin American-Statesman reported Sunday.

Charges against Luther were dropped after tests affirmed that the chemical was epitestosterone rather than testosterone, which is illegal. Luther said he used epitestosterone to treat his inflamed shoulder.

Epitestosterone is not available by prescription and has no medical use, said Dr. William Taylor, a specialist in anabolic steroids. But the drug can be used by athletes to increase the level of the hormone testosterone, a practice banned in all sports.

"If an athlete has 24 hours notice, he can beat the drug test every time by using epitestosterone," Taylor, a spokesman for the College of American Sports Medicine, said.

Taylor said athletes can inject the chemical an hour prior to a drug test and still pass the test.

"Athletes are very savvy, and this is just another example of it," said Frank Uryasz, NCAA director of sports sciences.

Luther said he was using the chemical for pain and inflammation following shoulder surgery two years ago.

"I was told to rub it on my shoulder," Luther said. "That's what the doctor told me to do. It was given to me by a doctor in Houston."

Luther declined to name the doctor.

"We knew it was not a steroid, that it wasn't anything," said David Minton, Luther's attorney. "It was epitestosterone. . . . It was very clear what it was. He was taking it under the advice of a physician in Houston."

But several experts say the drug is useless in reducing shoulder pain and inflammation.

Don Leggett, a compliance officer with the U.S. Food and Drug Administration in Washington, said the chemical's only use is to camouflage steroid use.