Cobalt is a trace element which has been shown to have performance-enhancing properties by stimulating the production of red blood cells.
This property was first reported as early as the 1930s, and it was used in the treatment of different types of anemia in humans.
However, its toxic effects were discovered early on, too. It can cause damage to the thyroid gland and can be toxic to the heart in excessive amounts. It can thicken the blood and increase the risk of heart attacks. Nerve problems can also arise. Studies have suggested there is an increased risk of tumors developing.
Cobalt has a similar effect to erythropoietin (EPO) in stimulating production of red blood cells. This, in effect, lifts the oxygen-carrying capacity of the blood, hence boosting performance.
Research from the 1940s and 1950s showed that dosing mice with cobalt produced a 30 percent lift in the number of red blood cells.
Despite its toxic effects, cobalt has reportedly been used by human athletes to boost performance, and reports in recent years identify its use as a growing concern among racing jurisdictions around the globe. Its use in racing is estimated to go back six or seven years, perhaps longer.
Cobalt is a naturally occurring substances and horses will ingest tiny amounts in their daily rations. It is understood that it is generally given to racehorses in the form of a cobalt salt – cobalt chloride. No prescription is needed in most jurisdictions to obtain it.
Testing for cobalt has created challenges for racing bodies and their scientific advisers. These included developing tests that were accurate enough to stand up for legal scrutiny, and setting a threshold for the substance, above which a horse would be deemed to have been given cobalt deliberately.
There are other challenges, too. One is the comparatively short window in which cobalt remains in a horse’s system – perhaps only four to six hours.
In human doping cases, cobalt is usually given by injection. In horses, it can be given easily as a powder, as a feed supplement, or by injection.
Reports have suggested that horses can have a strong reaction to a dose, with accelerated breathing and heart rate. Some have collapsed and even died during subsequent exercise.