U.S. marathoner Shadrack Biwott, who completed seventh on the 2016 U.S. Olympic Marathon Trials and third on the 2018 Boston Marathon, has acquired a four-year suspension after testing constructive for erythropoietin (EPO) in early 2024. Biwott is 40.

Impartial Arbitrator Imposes 4-Yr Sanction on Observe & Area Athlete Shadrack Biwott for Anti-Doping Rule Violation https://t.co/HCwdplXbir

— USADA (@usantidoping) August 27, 2025

The Kenya-born marathoner was examined out of competitors on Jan. 25, 2024, simply days earlier than the U.S. Olympic Marathon Trials in Orlando, Fla., the place he dropped out after 15 miles (24 km). USADA acquired affirmation of his constructive check on Feb. 23, and Biwott was instantly provisionally suspended.

Biwott requested a check of his B pattern, which got here again constructive on March 18, 2024, once more exhibiting the presence of EPO. In line with the USADA report, his blood check additionally revealed an adversarial analytical discovering. EPO is a banned substance underneath the World Anti-Doping Company (WADA) code, because it boosts endurance efficiency by growing the physique’s oxygen-carrying capability.

The case took practically 18 months to conclude as a result of the arbitrator agreed to delay the listening to whereas Biwott remained provisionally suspended so he might examine the supply of the constructive check. He argued the laboratory evaluation was invalid, however the pattern was reviewed by 4 impartial scientists worldwide, every confirming the identical end result: Biwott’s pattern was constructive for EPO.

Biwott’s four-year ban is retroactive to Feb. 23, 2024, the date of his provisional suspension. He has additionally been disqualified from all outcomes courting again to Jan. 25, 2024, together with forfeiture of medals, factors and prize cash. He might be 43 when his suspension is up in 2028.