Doctor at center of Peyton Manning doping allegation denies everything and trashes key witness

The doctor heading the anti-aging clinic that reportedly provided human growth hormone (HGH) to Denver Bronco's quarterback Peyton Manning has lashed out against Al Jazeera and a former "unpaid intern" who's at the center of the broadcaster's investigation into the supposed doping.

Dr. Dale Guyer, founder of The Guyer Institute, said he has "no reason" to believe allegations linking Manning and other NFL and Major League Baseball athletes to performance enhancing drugs "are based in fact or have any truth." 

He went on to say "former unpaid intern" Charles Sly "purposely fabricate[d] and spread stories that are simply not true." 

Earlier in the day, Sly took to YouTube to recant statements he gave to Al Jazeera on a hidden camera interview in which he implicated Manning and his wife, Ashley, as being recipients of HGH through The Guyer Institute. 

Guyer went on to contradict key elements of the Al Jazeera story, including the timeline on which Sly worked for him. In Al Jazeera's reporting, Sly is said to have worked at The Guyer Institute at the same time Manning was recovering from surgery that kept him sidelined during the 2011 season. 

"Sly was never an employee of the Guyer Institute and his brief three-month internship occurred in 2013, during which time Peyton was not even being treated or present in the office," he said in a statement.