S2 Erythropoietin (EPO)


Erythropoietin (EPO) is a natural hormone produced by the kidney that stimulates the production of red blood cells (erythrocytes) in the bone marrow. The ultimate effect is an increase in exercise endurance and a reduction of recovery time. Its improper use for doping purposes is prohibited.

Synthetic EPO was developed in the 1980s. It is mostly used to treat anaemia. People with chronic kidney disease nearly always suffer from anaemia because their kidneys completely or partially fail to produce EPO.

Effect of EPO

EPO is a glycoprotein hormone produced in the kidneys. A reduced supply of oxygen to the body (e.g. when at high altitudes) triggers the production of EPO. EPO is distributed to the body through the blood vessels and stimulates stem cells residing in the red bone marrow to transform into red blood cells (erythrocytes). The maturation of stem cells in the bone marrow via young red blood cells (reticulocytes) into functional erythrocytes takes five to nine days.

Red blood cells transport oxygen from the lung to the tissues (e.g. to the muscles). They also play an important role in the removal of carbon dioxide from the muscles. An increased amount of red blood cells thus leads to higher exercise endurance and faster recovery.

This effect can be achieved naturally by altitude training and artificially by the illicit administration of the EPO drug or by blood doping. More in-depth information on these topics can be found in the module “M1 Manipulation of blood”.

Erythropoietin (EPO) is a hormone produced in the kidneys when the oxygen supply to the body is reduced. The hormone produced is released into the blood circulation and stimulates the transformation of blood stem cells into red blood cells (erythrocytes) in the red bone marrow. Administration of synthetic erythropoietin leads to the increased formation of erythrocytes that transport oxygen from the lung via the blood circulation to the tissues. This enhances the oxygen supply of the musculature. The result is an increase in exercise endurance.

⬆ Oxygen supply

⬆ Exercise endurance

Side effects and consequences of EPO abuse

The increased formation of red blood cells stimulated by EPO raises the proportion of formed elements in the blood (haematocrit). The blood becomes more viscous (less fluid) and blood pressure rises. Especially when the body is dehydrated after strenuous exercise, this thickening of the blood promotes thromboses that may cause myocardial infarction, a stroke, or in the worst case, death. The risk of developing cancer also rises when EPO is abused.

Affected sports

Because EPO increases the number of red blood cells in the blood, more oxygen can be transported to the muscles and, in return, more carbon dioxide can be removed from them. As a result, the muscle fatigues less quickly and exercise endurance increases. EPO is therefore used mainly in endurance disciplines. In the perception of the public, improper EPO use in professional cycling has gained the greatest attention. Other endurance disciplines such as cross-country skiing, biathlon, marathon, ice speed skating and triathlon have also made headlines.

Doping with EPO in many different sports

In athletics, EPO is used not only by long- and middle-distance runners. In the course of the disclosures around the BALCO scandal in the USA as from 2003, it was revealed that some sprinters (Kelly White, Dwain Chambers) had also consumed EPO. EPO is used with the intent to shorten regeneration time after exhaustive periods of training or competitions. This means that nearly all athletes in all sports are vulnerable to the abuse of EPO. Cases have been documented from boxing, weightlifting and even from equestrian sports. Suspicions stubbornly persist that the Italian football club Juventus Turin carried out systematic doping with EPO in the 1990s.