“You would foil the system,“ Armstrong said on Bill Maher‘s Club Random podcast.. “What I always said, and I’m not trying to justify what I said as something I would want to repeat again, but one of the lines was, ‘I’ve been tested 500 times and I’ve never failed a drug test’.
“That’s not a lie. That’s the truth. There was no way around the test. When I pissed in the cup and they tested the piss in the cup, it passed. Now, the reality and the truth of all of this is, some of these substances, primarily the one that is the most beneficial, has a four-hour half-life. So certain substances, whether it be cannabis or anabolics, or whatever, have much longer half-lives.
“You could smoke that joint and go to work driving your tractor [and] in two weeks test positive, because the half-life is much longer. With EPO, which was the rocket fuel that changed not just our sport but every endurance sport, you have a four-hour half-life, so it leaves the body very quickly. With a four-hour half-life, you can just do the math.”
Lance Armstrong reveals how he passed drugs tests to win seven Tour de France titles (msn.com)