UCI Issues Guidance on Ketone Use in Cycling, Sparks Debate

The Union Cycliste Internationale (UCI), the governing body for professional cycling, yesterday issued a statement clarifying its position on the use of ketone supplements by athletes, neither banning nor recommending their use but advising against it.

The UCI’s guidance, released on 2025-10-21, comes as ketone supplements gain popularity among endurance athletes seeking a potential performance edge. The organization stated it “does not recommend” the use of ketones, but also acknowledged it currently has no grounds to prohibit them under existing anti-doping regulations. This position has led to criticism from some supplement brands who argue the UCI’s stance creates unnecessary ambiguity.

Several industry representatives have voiced concerns, suggesting the UCI’s intervention is “puzzling” and introduces further “grey areas” into anti-doping protocols. The debate centers on the fact that ketones are naturally produced by the body during periods of low carbohydrate intake, making it difficult to establish a clear line between natural physiological processes and artificial supplementation. This uncertainty could impact athlete testing and fair play. For more on the science behind ketones, resources are available from Healthline.

The UCI’s decision highlights the ongoing challenge of regulating performance-enhancing substances in sport, particularly those that exist in a complex physiological space. The organization has indicated it will continue to monitor research on ketones and reassess its position as needed, and is currently reviewing its prohibited list for 2026. You can find more information about the UCI’s anti-doping rules here.

The UCI stated it will continue to collaborate with the World Anti-Doping Agency (WADA) to ensure a level playing field for all competitors.