American Ryan Martin has been suspended for four years over a failed drugs test following a bout against Scotland's Josh Taylor in Glasgow.
The 26-year-old tested positive for metabolites of testosterone after the fight on 3 November, 2018.
UK Anti-Doping said Martin's suspension begins from the date of that fight. Martin claimed the banned substance had been contained within a supplement.
Taylor won the super-lightweight fight, Martin's first loss in 23 bouts.
Last month Taylor secured the IBF, WBA and Ring Magazine world super-lightweight titles with victory over Regis Prograis in London.