The supplement industry is a multi-billion dollar industry with many of the products targeted toward athletes and achieving optimal performance. Historically, endurance athletes have used a number of methods to try to increase erythrocyte (red blood cell-RBC) production in attempts to boost oxygen carrying capacity and perform better during aerobic exercise. A number of growth factors in the body can stimulate RBC production including erythropoietin (EPO). EPO is the primary growth factor that promotes the formation and release of RBCs from bone marrow. Although EPO itself is a banned substance, supplement companies have sought other means by which they can increase EPO production in the body in order to stimulate RBC synthesis. One natural product toted to stimulate EPO production is Echinacea and can be found in the product EPO-Boost™. Our global hypothesis is that supplementation of EPO-Boost™ will be an effective way to increase oxygen carrying capacity and improve maximal oxygen consumption in adult endurance athletes.