The Athletics Integrity Unit (AIU) announced the suspension on Monday.
Korir is being punished after traces of the banned substance CERA were found in his body. The substance stimulates the production of red blood cells and acts as a blood doping agent.
The suspension is effective from January 8 of this year, and all of his results from October 3, 2025, will be erased.
The Kenyan won the New York Marathon in 2021. Since then, he has taken a second place and two third places in the prestigious race.
Kenya is currently rocked by a major doping scandal. In early March, the country's National Anti-Doping Agency (Adak) suspended 27 athletes, most of them runners, for violating doping rules, pending investigations.
