Kiprop had argued his urine sample, which was taken out of competition, could have been tampered with by his testers, who had tipped him off about their visit and taken a payment from him.
But the AIU, an independent body managing all doping-related matters for athletics, said they were satisfied that there had been no interference and an IAAF Disciplinary Tribunal on Saturday suspended him for four years effective February 2018.
He had been tentatively suspended by the AIU in May last year.
"The (AIU) panel is aware that its order will interrupt, and may even terminate, the athlete's sporting career and cast a shadow over his impressive competitive record," it said in a statement.
"But in its opinion the laboratory results viewed in the context of the evidential record and the regulatory framework unit admit of no other conclusion than the case against the athlete is convincingly made out."
Kiprop can appeal his case to the Court of Arbitration for Sport (CAS). He continues to maintain his innocence.
“There is no justice in the world. Not every prisoner in jail is guilty,” he told Kenyan media on Saturday. “I will consult my lawyer to see if I will appeal at CAS but no matter the outcome I will be back stronger.”
Kiprop was awarded the 1500m gold medal from the 2008 Summer Olympics in Beijing after original winner Rashid Ramzi tested positive for doping. Kiprop won his three world titles in 2011, 2013 and 2015.
(Reporting by Hardik Vyas in Bengaluru and Gene Cherry, editing by Tony Lawrence)
