The Court of Arbitration for Sport has upheld the four-year ban imposed on athletics coach Alberto Salazar for anti-doping violations.
Salazar, who coached four-time Olympic champion Mo Farah among many athletes, and Dr Jeffrey Brown were banned in 2019 by the United States Anti-Doping Agency (USADA).
American Salazar, former head of the now-closed Nike Oregon Project, launched an appeal against the decision.
It was confirmed by the Court of Arbitration for Sport (CAS) on Thursday that the bans handed out to Salazar and Brown, who has worked as a physician and endocrinologist, would stand.
A CAS statement said the pair had "committed a number of anti-doping rule violations".
CAS ruled that Salazar was guilty of being in possession of testosterone, complicity in Brown's administration of a prohibited method and tampering with the doping control process.
Following news of Salazar's ban two years ago, Nike shut the Oregon Project, its elite training group for distance athletes.
British long-distance runner Farah has never failed a drugs test or been accused of doping and parted ways with Salazar in 2017.
CAS said that aspects of USADA's handling of the cases against Salazar and Brown "seemed to be out of proportion and excessive when compared to the severity and consequences of the ADRVs [anti-doping rule violations] that have been established".
In a media release, CAS added that it "emphasised that none of the ADRVs directly affected athletic competition, and that there was no evidence put before the CAS as to any effect on athletes competing at the elite level within the NOP [Nike Oregon Project]".