During his first Tour de France victory, in 1999, Armstrong’s drug of choice, according to the sworn affidavits, was the blood-boosting hormone known as EPO. At that time, there was no test for EPO, which is a cloned form of human hormone rather than a synthetic product. <br /><br />But when rumors began circulating about the arrival of a test for EPO, Armstrong and some of his teammates switched to withdrawing and then reinfusing their own blood. Again, it was a technique initially without a test.<br /><br />Ferrari discovered that when regular, if small, doses of EPO were injected directly into veins rather than under the skin, Armstrong and others could continue using the hormone without fear of a positive test result, the report said.