Kenya's World Marathon Champion Jepchirchir Provisionally Banned After Testing Positive for Banned Blood Booster

Kenya's world marathon champion Peres Jepchirchir has been provisionally suspended after testing positive for the banned blood booster EPO in a sample taken before her Sydney Marathon victory in August, the Athletics Integrity Unit (AIU) has said.

The AIU said the out-of-competition sample, collected in Kenya, returned an adverse analytical finding for EPO (erythropoietin), a substance that boosts the production of red blood cells. Such drugs are alleged to increase stamina in long-distance running, which is why they sit on athletics' prohibited list.

Her agent, Gianni Demadonna, said in an emailed statement that he felt terrible about what happened and that, in his view, it is only right that an athlete who uses performance-enhancing drugs should be disqualified. The agent's remarks have intensified discussion around the case.

Sydney Marathon organisers said they were extremely disappointed to learn of Jepchirchir's provisional suspension. They added, however, that she is entitled to due process and that they will make no further comment until that process has concluded.

The organisers said their commitment to clean sport is unwavering. Every athlete who lines up in Sydney deserves to race on a level playing field, they said, and every participant and spectator deserves to trust the result they see at the finish line.

Sydney officials added that, alongside their fellow Abbott World Marathon Majors, they have invested in increased out-of-competition testing in partnership with the AIU, and that they will keep standing firmly with the athletes who compete cleanly.

The 33-year-old is a former Olympic champion and former half-marathon world record holder, as well as a four-time World Marathon Majors winner. She won gold at the Tokyo Games in 2021 and has also claimed major marathon victories in New York (2021), Boston (2022) and London (2024).

In Sydney in August, Jepchirchir dominated the women's race, pulling clear of the field to finish in 2:18:31, more than three minutes ahead of second-placed compatriot Irine Cheptai. That victory is now under a cloud.

This is not the first doping shadow over Kenyan athletics. Last year, Kenya's women's marathon world record holder Ruth Chepngetich was banned for three years after admitting anti-doping rule violations involving hydrochlorothiazide (HCTZ), a prohibited diuretic, though her world record of 2:09:56 remained on the books because it was set before her positive test.

In Jepchirchir's case, due process will now run its course. A provisional suspension is not a final finding on the charge; hearings and appeals remain open to her. If the violation is proven, however, she could face the loss of results including the Sydney win, alongside a lengthy ban.

The fall of one of world athletics' most successful marathon runners has renewed questions about doping control in long-distance running. All eyes are now on the AIU's next decision.