The American took an in-competition test after a third-round knockout defeat to Joshua, with positive results for the prohibited substance.
Molina had already been handed a provisional suspension in October, and UK Anti-Doping (UKAD) has now confirmed that he will be banned for two years, with the sanction backdated to the start of that temporary sentence.
UKAD chief Nicole Sapstead said: "Every athlete is solely responsible for what is in their system and must adhere to the strict liability principle.
