French fencer Ysaora Thibus, the 2022 women’s foil world champion, has been cleared of doping charges after proving that the banned substance detected in her system came from kissing her then-partner, American Race Imboden. Thibus was facing a four-year ban after testing positive for ostarine in January 2024, an anabolic agent banned by the World Anti-Doping Agency (WADA) since 2008.
The 33-year-old athlete argued that ostarine had entered her body unintentionally when she kissed Imboden, who was taking a supplement containing the substance. WADA brought the case before the Court of Arbitration for Sport (CAS), which finally acquitted her in a ruling issued on Monday.
CAS recognizes contamination through kissing
In its statement, CAS explained that “the Panel considered the evidence and noted that it is scientifically proven that ingesting a dose of ostarine similar to that consumed by Ms. Thibus’s then-partner would have left enough in the saliva to contaminate another person through kissing.” The court concluded that the violation of anti-doping rules was unintentional and that Thibus was not at fault or negligent.
WADA, through its spokesperson Andrew Maggio, expressed its “disappointment with the outcome” of the case, although it declined to comment further. “WADA questioned the scenario presented by the athlete based on the facts and science of this particular case,” he said in an email.
A case closely followed during the Olympics
Thibus has been in the media spotlight for the past 18 months, especially at the 2024 Paris Olympics, where she was one of the French team’s great hopes. Following the positive test, the International Fencing Federation (FIE) immediately suspended her, although in May she was acquitted by the federation’s disciplinary panel, allowing her to compete in Paris pending appeal.
At the Olympics, Thibus was eliminated in the round of 32, falling far short of initial expectations. Throughout the process, her defense maintained the same line of argument, as her lawyer Joëlle Montlouis explained to the French media outlet L’Equipe: “At no point did we stray from our course. From the first instance to the hearing at the CAS, we maintained the same line, faithful to the reality of the facts.”
The precedent of accidental contamination in sport
Thibus’ case joins other recent episodes in which athletes have claimed accidental contamination to explain the presence of banned substances in their tests. Among the best-known examples are Russian skater Kamila Valieva, who claimed to have ingested trimetazidine through a strawberry dessert prepared by her grandfather, and several Chinese athletes who attributed their positive test for metandienone to the consumption of contaminated hamburgers.
In its ruling, the CAS took into account the amount of ostarine present in Imboden’s supplement, the possible transmission through saliva, and the cumulative effects of prolonged exposure. This case opens a new chapter in the interpretation of anti-doping rules and the consideration of exceptional circumstances in elite sport.
