The Dutch captain had remained adamant that he was innocent of any offences, and Uefa's decision has basically asserted that the defender was completely unaware that he had taken the drug.
De Boer's year-long ban will now only run until the end of August, with the commission deciding that, despite the fact that players should be completely responsible for what drugs they ingest, there had to be mitigating circumstances.
In an official statement, Uefa said: "The 12-month suspension of FC Barcelona's Dutch international defender Frank de Boer following a positive doping test earlier this year has been reduced on appeal and will now end on 31 August this year.
"The decision follows a meeting of Uefa's Appeals Body at its headquarters in Nyon, Switzerland.
"It is more than likely that the appellant took the prohibited substances by means of contaminated food supplements."
De Boer admitted he was relieved to have his name cleared.
"I knew it, now I feel free, I think it was decisive to undergo the lie-detector," said De Boer.
The ban could have major world-wide repurcussions with the likelihood that many of the nandrolone related drugs bans will be slashed.
Edgar Davids, an international team-mate of De Boer, Fernando Couto of Sampdoria and several less high profile cases are all likely to be appealed through Uefa.
