Hi mellow - EPO is big in the endurance sports such as cycling. You will see some pro riders that do it. It is also called blood doping. The Tour de France is a long race (over 2000 miles) which you need a lot of aerobic oxygen to sustain the large mountain climbs. EPO is thought to help with this since it increases your RBC's which is a component that carries Oxygen. For bodybuilding, I doubt it would be great help to you. The only help would be you might be able to do more reps in a set before the burn set in (this is lactic acid from lack of oxygen). EPO, or erythropoietin, is a hormone naturally produced by the body but now it is genetically engineered. EPO artificially increases the level of red blood cells and therefore enhances aerobic capacity. I guess if you intend to do more aerobic activity, then it would help. The old way of doing this way by giving blood twice a week for 4-6 weeks and then right before a race, you get the blood "spinned down" or separated and inject just the RBC's back into your body. When giving blood, your body will produce more blood components in it's place, hence more RBC's. You would be back at your normal level, then by injecting your RBC's (from the blood given earlier), you would thus increase your total RBC's, which would allow you to carry more O2 in your system to your muscles. I really do not see much benefits in bodybuilding and it can be dangerous. I hope this helps you. If it does, positive karma is always welcome my way! Geoff