Benn was formally charged by UKAD in April after twice testing positive for the female fertility drug clomifene in the build-up to October's domestic catchweight showdown with Chris Eubank Jr.
But the 26-year-old son of British great Nigel Benn revealed in a social media post that the charge had been dismissed.
"Today marks the end of a gruelling 10-month process, during which the WBC (World Boxing Council) had already decided I was innocent of any wrongdoing," Benn said.
The welterweight said he has been "vindicated for the second time" after a hearing with the National Anti-Doping Panel and UKAD.
"Hopefully, the public and various members of the media can now understand why I have maintained my innocence so strongly all the way through," he added.
"The UKAD process has now formally ended and I remain free to fight."
UKAD issued its own statement in an attempt to provide clarity.
A spokesman said it had taken the "exceptional step" of publicly disclosing details of Benn’s provisional suspension and charge in April following reports from the media and comments made by Benn.
The spokesman added: "UKAD notes that Mr Benn has made further public comments today regarding proceedings before the independent National Anti-Doping Panel.
"UKAD can confirm Mr Benn is no longer provisionally suspended under the UK Anti-Doping rules."
The body said it was unable to make further public disclosures in accordance with its rules.
October's proposed bout was intended to be a continuation of the Benn v Eubank feud in which the rivals' fathers - Nigel Benn and Chris Eubank Sr - battled it out in two ferocious contests in the early 1990s.
A catchweight fight of 157 pounds (71.2 kilograms) was agreed for the sons to continue the family feud, meaning Benn would have had to move up two weight divisions and Eubank lose three pounds.
