As athletes make gains in size, speed, and agility, so do the tests that ensure those athletes are doing so without the assistance of illegal, performance-enhancing substances. Host Dr. Gary Kohn speaks with Dr. Don Catlin, founder and chief executive officer of Anti-Doping Research, Inc., in Los Angeles, and former head of the UCLA Olympic Analytical Labs, who specifically highlights pharmaceutical testosterone, its production signature, and the carbon isotope ratio test that exposes its illegal use.