Reigning World marathon champion Peres Jepchirchir/HANDOUT

Reigning World marathon champion Peres Jepchirchir has been provisionally suspended by the Athletics Integrity Unit (AIU) following an adverse analytical finding for erythropoietin (EPO), a prohibited substance used to enhance endurance performance.

‎EPO is a naturally occurring hormone produced by the kidneys that stimulates the bone marrow to produce more red blood cells, which transport oxygen throughout the body.

‎When misused as a form of blood doping in sport, synthetic or recombinant EPO is injected to artificially increase the red blood cell count, enhancing the body's oxygen-carrying capacity and potentially improving endurance performance.

‎In a statement posted on its X account, the AIU revealed that the Kenyan marathon star had been provisionally suspended after an out-of-competition sample collected in Kenya ahead of her recent triumph at the Sydney Marathon returned an adverse analytical finding for EPO.

‎"The AIU has provisionally suspended reigning World and former Olympic champion, Peres Jepchirchir, after an out-of-competition sample, collected in Kenya before her recent Sydney Marathon victory, returned an adverse analytical finding for EPO," the statement read.

‎"The highly decorated Kenyan marathon runner, a former world record-holder in the half-marathon, is a four-time World Marathon Major winner, having captured the Sydney Marathon (2026), the London Marathon (2024), the Boston Marathon (2022) and the New York Marathon (2021)."

‎Jepchirchir's latest competitive outing was at the Sydney Marathon, where she stormed to victory in 2:18:31, further underlining her prowess over the classic 42.195km distance.

‎The Kenyan spearheaded a memorable Kenyan one-two finish in Sydney, with 2017 world cross-country champion Irine Cheptai finishing second in 2:22:11, while Ethiopia's Shure Demise completed the podium in 2:22:33.

‎Jepchirchir had raced just twice over the marathon distance last season.

‎She first captured the World Marathon Championships title in Tokyo in September, producing a gutsy performance to clock 2:24:43 and edge Ethiopia's Tigst Assefa, who finished a close second in 2:24:45.

‎Uruguay's Julia Paternain claimed the bronze medal in 2:27:43.

‎The Kenyan then brought her campaign to a close with a runner-up finish at the Valencia Marathon, clocking an impressive 2:14:43 behind compatriot Joyciline Jepkosgei, who won in 2:14:00, as Belgium's Chloe Herbiet completed the podium in 2:20:38.

‎Her marathon resume includes the Tokyo 2020 Olympic gold as well as her 2025 world title.

‎On the half marathon scene, she boasts three World titles from Cardiff 2016, Gdynia 2020 and Riga 2023.