A banned hormone that stimulates red blood cell production, increasing oxygen-carrying capacity and endurance performance.
Erythropoietin (EPO) is a naturally occurring hormone produced by the kidneys that regulates red blood cell production. In cycling, synthetic EPO became one of the most infamous performance-enhancing drugs during the 1990s and early 2000s.
• Stimulates bone marrow to produce more red blood cells • Increases hematocrit (percentage of red blood cells in blood) • Enhances oxygen transport to muscles • Significantly improves aerobic capacity and endurance
• VO2 Max increases of 5-15% have been documented • Improved time to exhaustion at threshold intensities • Enhanced recovery between efforts • Estimated performance gains of 3-10% in endurance events
The EPO Era (1990s-2000s): • Widespread use in professional peloton • Lack of reliable detection methods until late 1990s • Associated with numerous high-profile doping cases • Led to significant changes in anti-doping protocols
• Lance Armstrong's U.S. Postal Service team • Multiple Festina Affair riders (1998 Tour de France) • Tyler Hamilton and Floyd Landis admissions
• Direct EPO tests via urine and blood samples • Athlete Biological Passport (ABP) monitoring • Hematocrit limits (previously 50%, now monitored via ABP) • Longitudinal tracking of blood markers
The Athlete Biological Passport revolutionized detection by tracking individual baseline values over time, making micro-dosing strategies detectable.
• Regular in-competition and out-of-competition testing • Whereabouts requirements for elite athletes • Biological Passport monitoring • Retroactive testing of stored samples
• Naturally stimulates EPO production • Increases red blood cell count legally • Common practice: 2-4 weeks at 2,000-3,000m elevation
• Sleep in simulated altitude conditions • Legal performance enhancement method • Used by many professional teams
• Transparent testing protocols • Third-party verification programs • Public disclosure of test results • Education about risks and ethics
Understanding EPO is crucial for comprehending cycling's doping history and the ongoing fight for clean sport. Modern testing protocols and the Biological Passport system were developed specifically to combat EPO use.
The biggest misconception is that EPO use is a thing of the past. While detection has improved dramatically, sophisticated micro-dosing and new variants continue to challenge anti-doping efforts. Another myth is that all professional performances are drug-aided - many athletes achieve exceptional results through legitimate training, genetics, and legal optimization methods.