Browner had been appealing what the league said was his second violation of the policy. NFL.com reported Browner had been given an offer by the league to reduce the penalty, but chose to fight the decision.
With the denial of the appeal, Browner faces a possible 12-month suspension.
Browner will become a free agent at the end of this season. He has played only eight games in 2013 due to a groin injury.
The most recent violation stems from a series of drug tests that the league says Browner skipped. Browner, a former star in the Canadian Football League, has argued that he was not in the NFL when those tests were scheduled.