The 30-year-old Adams tested positive for Stanozolol on May 26 and the ban will run until June 13 2014, said UK Anti-Doping.
The body's legal director Graham Arthur said the finding resulted from ’’a targeted, intelligence-led test.’’
Adams, whose record stands at 13-4-1 in his five-year professional career, said the Stanozolol may have come from medication he was using for a neck injury.
But Arthur in rebuttal said that Stanozolol ’’is banned at all times in sport, there is no reason for it to be found in an athlete’s system."
Adams' fourth-round stoppage defeat to Harrison - who meets fellow British heavyweight contender David Price this month - in Brentwood was his highest-profile fight.