An explosive al-Jazeera report that Peyton Manning received supplies of human growth hormone through his wife has been called into question, after the primary source says he recanted the allegations he made against Manning.

The allegations against the Denver Broncos quarterback came in an investigative documentary, The Dark Side, released by al-Jazeera Sunday on the prevalence of doping in global sports. In the documentary, British hurdler Liam Collins goes undercover to demonstrate the ease of obtaining performance-enhancing drugs. He meets with several medical professionals who boast they have already helped other professional athletes.

One medical professional was Charlie Sly, who identifies himself as a pharmacist who worked at an anti-ageing clinic where he says Manning was obtaining the drugs through his wife during his recovery from neck fusion surgeries in 2011 in Indianapolis. Human growth hormone is banned by the NFL.

Sly said the the clinic, the Guyer Institute, was sending HGH to Manning “all the time” via his wife Ashley so that his name was not attached to them. He was a player for the Indianapolis Colts at the time.

But Sly told ESPN’s Chris Mortensen that once he realized al-Jazeera planned to use his statements in its report, he recanted his story to al-Jazeera and said he “made up” details. He told Mortensen he was trying to get into the supplement business.

“When I was there, I had never seen the Mannings, ever. They were not even living there at that time,” Sly said. “Someone who worked there said they had been there before. That was the extent of any knowledge I had. I feel badly. I never saw any files. This is just amazing that it reached this point.”

At the end of the documentary, al-Jazeera notes that Sly said his statements about athletes were “false and incorrect”, but doesn’t elaborate further.

Manning’s agent virulently denied the allegations as “baseless and absolutely false” in the documentary, and Manning reiterated that denial after the report’s release, saying: “The allegation that I would do something like that is complete garbage and is totally made up. It never happened. Never.

“I really can’t believe somebody would put something like this on the air. Whoever said this is making stuff up,” he added.

Manning admitted in a televised interview with ESPN on Sunday to seeking holistic treatments such as hyperbaric oxygen and nutrient therapy at the Guyer Institute, but categorically denied taking PEDs or anything that was ever shipped to his wife.

The documentary shows more explicit links between Sly and other players. One, baseball player Taylor Teagarden, is caught on camera waiting at Sly’s door when Collins arrives. In the footage, Teagarden talks openly about having used the steroid Delta-2. He says he took it for two weeks and later took a urine test which revealed nothing.

The report also suggests the widespread failure of testing regimens. Eddie Dominguez, who worked with MLB’s investigative unit, estimated that at least some 100 ball players are doping. But he called it a cat-and-mouse game. “As long as they know what the testing procedure is, they’ll always be able to beat it,” he said in the documentary. Last season, more than 8,000 tests were performed by the MLB, and only 10 resulted in players being disciplined, according to al-Jazeera.

The NFL only started testing for human growth hormone in 2014, and nobody has yet tested positive.