In a release from its Colorado headquarters, USADA said that Mutinda admitted the use of various banned performance enhancing drugs after twice testing positive for 19-norandrosterone, a metabolite of an anabolic agent.
In the wake of the postive tests, 40-year-old Mutinda also admitted the use of blood-boosting hormone EPO and the diuretic furosemide, used as a masking agent.
As a result of an in-competition positive test at the 2014 Austin Marathon on February 16 of last year, Mutinda has been stripped of his title in the Texas race, which he won in 2hr 14min 16sec.
He has in fact been stripped of all results from December 15, 2013, the date on which USADA said records show he was first administered EPO.
Mutinda’s ban comes as Kenya grapples with a doping problem that reached crisis proportions with the two-year ban in January of top marathoner Rita Jeptoo — winner of Multiple Chicago and Boston marathon titles.
More than 35 Kenyan athletes have been suspended over the last two years for doping offences, with Kenyan sports bosses accused of inaction on the doping issue.
The doping offences have stunned Kenya, whose distance runners are national heroes.
Kenya have formed a new anti-doping agency to regulate the testing of athletes, in partnership with China and Norwegian agencies and the World Anti-Doping Agency (WADA).