Kenya’s Joyline Chepngeno has received a doping ban after her win of the 2025 Sierre-Zinal, where an in-competition test revealed the presence of the banned substance Triamcinolone Acetonide. Kenya’s Caroline Kimutai, who finished in second place, has been declared the winner.
Chepngeno received a two-year ban, which went into effect on September 8, 2025, and all of her results from August 9 forward are nullified. This includes her 2025 Sierre-Zinal win and her 2025 OCC win less than two weeks ago. Sierre-Zinal was part of both the World Mountain Running Association World Cup and the Golden Trail World Series, and OCC was the UTMB World Series Final for the 50k distance.
Joyline Chepngeno winning the 2025 Sierre-Zinal. On September 9, 2025, she received a doping sanction for failing an in-competition test and her result was nullified. Photo: World Mountain Running Association/Marco Gulberti
A statement from the Athletics Integrity Unit (AIU), which was started in 2017 by the International Association of Athletics Federations to combat doping, issued on Tuesday, September 9, reads:
“On the basis that the Athlete has admitted the Anti-Doping Rule Violations under Rule 2.1 ADR and Rule 2.2 ADR, in accordance with Rule 10.2.1 ADR, the AIU confirms by this decision the following Consequences for a first Anti-Doping Rule Violation:
- 15.1. a period of Ineligibility of two (2) years commencing on 8 September 2025; and
- 15.2. disqualification of the Athlete’s results on and since 9 August 2025, with all resulting consequences, including the forfeiture of any titles, awards, medals, points, prizes and appearance money.”
Chepngeno’s primary sponsor, Salomon, immediately announced that she was dropped from its roster.
Chepngeno had a breakout win at the 2024 Sierre-Zinal, storming to victory ahead of Scout Adkin (U.K.) and Mădălina Florea (Romania). She also won the 2025 Marathon du Mont-Blanc. The Kenyan seemed unstoppable, repeating her Sierre-Zinal victory this year and then having a strong battle with Miao Yao (China) before winning the 2025 OCC at the end of August.
Caroline Kimutai Declared 2025 Sierre-Zinal Women’s Champion, Women’s Podium Updated
Following this announcement, the Sierre-Zinal race organization announced in its own press release that Chepngeno is officially disqualified from the race and named Caroline Kimutai the winner of the 2025 Sierre-Zinal. This also shifts American Katie Schide into second and Maude Mathys (Switzerland) into third.
[In 2015, Maude Mathys received a warning without suspension from the Disciplinary Chamber for Doping Cases of Swiss Olympic for two positive tests for clomifene (previously clomiphene) after it was determined that she was mistakenly taking the drug without first obtaining a World Anti-Doping Agency Therapeutic Use Exemption.]
Caroline Kimutai of Kenya is the new 2025 Sierre-Zinal women’s champion. Photo: World Mountain Running Association/Marco Gulberti
Details on Joyline Chepngeno’s Doping Sanction
According to that press release on September 9 by the Athletics Integrity Unit, Chepngeno submitted an in-competition urine sample after her win at the 2025 Sierre-Zinal that tested positive for Triamcinolone Acetonide, a synthetic corticosteroid used as a painkiller that is a Prohibited Substance under the World Anti-Doping Agency. It is prohibited for use in competition without a Therapeutic Use Exemption.
After being notified of the positive test on September 8, Chepngeno said that she’d received an injection in her knee to help with pain in July 2025, but did not realize it was a banned substance. She apologized for the mistake and sent in an Admission of Anti-Doping Rule Violations and Acceptance of Consequences Form to the AIU.
The period of ineligibility for the violation is two years and started on September 8. Chepngeno will have to return all prize money and awards that she accrued since that date, including the 2,000 CHF prize purse from Sierre-Zinal.
Chepngeno’s coach, Julien Lyon, has also received a sanction from Sierre-Zinal, as is explained in that September 9 press release from the race organization. This is the second time in three years that Lyon, who heads up the Milimani Runners Kenyan trail running team, has been involved with a doping case at Sierre-Zinal. In 2022, Kenyan runner Mark Kangogo, who was also coached by Lyon, was issued a two-year ban after testing positive for Norandrosterone, an androgen and anabolic steroid, and Triamcinolone Acetonide, the same synthetic corticosteroid that Chepngeno was just sanctioned for. Kangogo’s two-year ban was reduced to one year after an early admission of the violation. Lyon and any runners associated with the Milimani Runners program have been banned from future editions of Sierre-Zinal.
Unfortunately, this is another positive doping test by a Kenyan endurance runner. In 2024, Kenya had more doping sanctions than any other country, ahead of India and Russia, pointing to what many experts are calling a systemic doping issue in Kenyan running.
Joyline Chepngeno winning the 2024 Sierre-Zinal. Photo: World Mountain Running Association/Marco Gulberti
