Peyton Manning: NFL investigation finds 'no credible evidence' of HGH use
An investigation into claims two-time Super Bowl winner Peyton Manning used performance-enhancing drugs found "no credible evidence", says the NFL.
Manning, 40, denied claims, aired by Al Jazeera, that he took human growth hormone after neck surgery in 2011.
The NFL said he was "fully co-operative" with the investigation.
Quarterback Manning won the NFL's most valuable player award five times and retired after winning the Super Bowl with the Denver Broncos last season.
The NFL said investigations would continue into allegations made against other players.
Green Bay Packers duo Clay Matthews and Julius Peppers, their former team-mate Mike Neal, and James Harrison of the Pittsburgh Steelers were also named in the Al Jazeera report.
All four have denied wrongdoing.