Erythropoietin (EPO) is a hormone that is naturally produced by the kidneys to stimulate the production of red blood cells. Red blood cells deliver oxygen to the tissues in the body, and EPO helps make more of them. EPO is used in a clinical setting to treat anemia due to cancer or its treatment. There are different types of EPO treatments, including epoetin alfa, epoetin beta, epoetin zeta, and darbepoetin alfa. EPO is also used as a performance-enhancing drug in sports, known as blood doping. By injecting EPO, athletes aim to increase the number of red blood cells and, consequently, their aerobic capacity. However, the use of EPO in sports is prohibited at all times under the World Anti-Doping Agency (WADA) Prohibited List.