Both erythropoietin (EPO) and Erythropoietin stimulating agent (ESA) benefit in bodybuilding and performance promote, particularly in endurance sports such as cycling, long-distance running and cross-country skiing. EPO and ESA can significantly improve the performance of bodybuilders by increasing the oxygen-carrying capacity of the blood. How EPO and ESA work? Erythropoietin Natural function: Erythropoietin is a hormone produced by the kidneys …