The ruling is the latest blow to Russia, whose track and field athletes were barred from the Rio Games.
The International Olympic Committee (IOC) on Tuesday stripped Russian weightlifter Apti Aukhadov of the silver medal he won at the 2012 London Games after a re-test of samples tested positive for drugs.
The 23-year-old finished second in the men's 85kg weightlifting event.
But re-analysis of Aukhadov?s samples from London resulted in a "positive test for the prohibited substances Dehydrochlormethyltestosterone(turinabol) and Drostanolone".
The ruling is the latest blow to Russia, whose track and field athletes were barred from the Rio Games and which is at the centre of a unprecedented doping scandal that led the IOC to seek a complete overhaul of global drug testing.
The IOC at the weekend called for all testing and sanctioning powers to be taken away from sports federations.
It wants the World Anti-Doping Agency (WADA) to set up a new global testing body and the Court of Arbitration for Sport to make all decisions on punishments for those caught cheating.
The IOC added that Ukrainian pole vaulter Maksym Mazuryk, who ranked 18th in the event in London, had been disqualified after re-analysis came back positive, also for turinabol.