The Union Cycliste Internationale (UCI)  has clarified that it has been analysing athlete samples for FG-4592 since 2011, when the hypoxia-inducible factor (HIF) stabiliser was added to section S2 of the World Anti-Doping Agency’s Prohibited List. Media reports had suggested that the UCI had decided to screen all samples from the 2015 Tour de France for FG-4592, after a number of positive tests for the substance.

On 29 July, the UCI suspended the Androni Giocattoli-Sidermec Pro Continental team for 30 days, after rider Fabio Taborre reported an adverse analytical finding for FG-4592. This followed a positive test from Chilean cyclist Carlos Oyarzun at the Toronto 2015 Pan American Games. In April, the French anti-doping agency (AFLD) confirmed a positive test for FG-4592 on race-walker Bertrand Molinet.

FG-4592, sometimes called ‘oxygen in a pill’, stimulates the production of erythropoietin (EPO) inside the body (endogenous). Unlike exogenous (externally administered) EPO, it is available in pill form and works in combatting anaemia by increasing an individual’s ability to produce red blood cells. As red blood cells contain iron, this helps combat anaemia, but red blood cells also carry oxygen around the body – specifically to the muscles. It is also understood that FG-4592 doesn’t raise blood pressure in the same way as EPO, reducing the risk of heart attacks due to ‘thickened’ blood.