Double Olympic champion Caster Semenya has lost her appeal against the introduction of a 2018 ruling that can require female athletes to take hormonal contraception to reduce testosterone levels. Semenya, who is hyperandrogenous and has higher levels of testosterone than most women, will have to take medication if she is to compete at the 2020 Tokyo Olympics, the International Association of Athletics Federations has ruled.

The Switzerland-based Court of Arbitration for Sport upheld the ruling on Wednesday. Reacting to the news on Twitter, Semenya posted a shrug emoji alongside the caption, "Sometimes it's better to react with no reaction."

The IAAF ruling has been controversial, with some criticizing it for unfairly targeting Semenya, who has continued to face scrutiny for having what some see as an "unfair advantage" over the competition. The ruling only impacts athletes who run between the distances of 400 meters and a mile. Semenya appealed the ruling, but the Court of Arbitration denied her request.

CAS stated that they had "some serious concerns" about the regulations, but "on the basis of the evidence submitted by the parties, such discrimination is a necessary, reasonable, and proportionate means of achieving the IAAF's aim of preserving the integrity of female athletes in the restricted events." At the age of 18, Semenya was forced to go through extensive sex testing after officials doubted the legitimacy of her 800-meter world championship victory in 2010.