Kenyan Marathon Runner Peres Jepchirchir Tests Positive for EPO

Kenyan marathon runner Peres Jepchirchir has tested positive for the performance-enhancing drug erythropoietin (EPO), the Athletics Integrity Unit (AIU) announced. The positive test occurred during a doping control conducted immediately before the Sydney Marathon, which Jepchirchir won on August 30.

A Decorated Career Under Scrutiny

Jepchirchir, 33, is widely regarded as one of the most successful marathon runners of the decade. Her victory in Sydney marked her fourth major marathon title, following wins in New York in 2021, Boston in 2022, and London in 2024. Her athletic resume includes an Olympic gold medal from the 2021 Tokyo Games in Sapporo, a world championship title from the 2025 Tokyo event, and previous world record times in both the marathon and half-marathon.

In December, she recorded a personal best time of 2 hours, 14 minutes, and 43 seconds in Valencia, which currently stands as the ninth-fastest time in history. Hailing from Turbo in Kenya’s Rift Valley, Jepchirchir had been viewed as a prominent figure in distance running, an area of the sport that has faced significant scrutiny regarding doping allegations in Kenya and Ethiopia.

Context of the Investigation

The AIU is responsible for managing doping control for elite athletics. The positive test for EPO, a substance used to increase red blood cell production and improve endurance, is considered a significant development given the athlete’s high profile. EPO is frequently targeted in testing protocols due to its detectability.

Why it matters: This development impacts the integrity of elite long-distance running, a sport where Kenyan athletes frequently dominate global podiums. The positive test of such a highly decorated champion raises serious questions about the prevalence of performance-enhancing substances in the sport and the efficacy of current anti-doping measures in East African training hubs.