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No matter what you think about Peyton Manning—he used, he didn't use, you don't care either way—one thing is certain in the wake of Al Jazeera's bombshell allegations: The NFL's drug-testing program continues to have a massive, gaping hole when it comes to HGH.

One veteran NFL player put it this way: "Steroids aren't the problem. HGH is the big problem. For the past four or five years, the league has been almost overrun by HGH. ... The new testing procedures aren't catching anyone, because players know there is almost no way to get caught."

Like the NFL's marijuana policy, the player said, a player using HGH will only get caught "if the NFL gets really, really lucky, like win-the-Lotto-every-month lucky."

Players Bleacher Report spoke to estimated that somewhere in the range of 10 to 40 percent of current players use HGH. Various former players have had similar and even higher estimates. Former quarterback Boomer Esiason once said 20 percent of the league used HGH. Former quarterback Brady Quinn estimated the number to be 40 to 50 percent on the Roughing the Passer podcast on CBS Sports.

This apparent rampant use of HGH over the past five years or more has created—as one player explained—a league of "superfreaks" who continue to run faster, jump higher and break records. Quinn said he believes this is behind the rash of injuries across the NFL this past season, and players interviewed by Bleacher Report had similar concerns: that the massive use of the drug, or others like it, will have long-term health ramifications. Their worries sound similar to the concerns expressed by some players in the 1980s and 1990s about concussions.

"The bodies of players are basically acting as chemistry sets," one veteran said. "What's going to happen to these guys five or 10 years from now?"

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All of this may change next season, when the league goes to a different type of test. Then, the league's policy could be much tougher. More on that in a moment.

For now, the league's testing program has no teeth, and a half-dozen players interviewed for this story say the reason why comes down to one word: isoform.

The NFL and union agreed to HGH testing in 2011. Testing did not begin until October 2014. The NFL says there are about 40 random tests a week during the regular season, five random tests per team during the postseason and other players who are subject to testing because of cause. Violators of the HGH policy are subject to a four-game suspension.

Adolpho Birch, the NFL's senior vice president for labor policy, was asked if an HGH user has been caught by the NFL's testing.

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"Remember, despite our efforts, the union would not agree to publishing the substances: Suffice it to say that it is as low as can be," Birch told Bleacher Report in an email. "But I keep trying to emphasize that doesn't mean the test is inferior, or that it is not sufficiently deterring use."

When Birch says "as low as can be," he is saying no player has been caught yet.

An email to George Atallah, the union's assistant executive director of external affairs, was not immediately returned.

Back to isoform: The problem, longtime anti-doping analyst Don Catlin told USA Today's Brent Schrotenboer in February, is that isoform testing only works if the player is tested within a few hours of using HGH. It "doesn't catch many people at all," he said. "It's not a test that's designed to really do that. It will catch you if you just used it a few hours ago, but if it's a day or more, it's not going to find you."

In other words, using the isoform test is the equivalent of the police staking out a house days after it was burgled.

Players say the entire player base is aware of this and that that is why there's no fear of the league's HGH testing procedure.

One player remembers a team union player representative briefing the team after the league and players agreed to the testing procedures. The message of the team rep, this player said, was that there's little chance any player would ever get caught under these rules.

But this is where things get interesting, because Birch said the league will soon use a different form of testing.

"We are currently using isoform," he said, "but I expect that we will add biomarker in the offseason."

As David Epstein wrote for SI.com's MMQB in July, "The biomarker test does not pick up doping within the previous two days, but the detection window extends back beyond that for at least a week, so it has the potential to be much more effective than the isoform test." That would dramatically increase the chances of a cheating player getting caught. This type of testing, like all testing, would have to be agreed upon by the union.

What exactly is HGH? It's a hormone that increases strength and reduces fat. Yet the characteristic of HGH that is also of great interest to NFL players is it helps the body heal from injury faster.

One of the only times the NFL catches HGH cheats are in instances like the one that involved former Patriots safety Rodney Harrison, who admitted to law enforcement officials in 2007 that he used HGH. This admission led to a four-game suspension.

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"I used it. I never had an issue with my groin ever again," Harrison, now an analyst, said on NBC this past week. "It wasn't smart. I put a foreign substance in my body and I don't know the long-term effects. I have a black cloud over my career. I played 15 years and that doesn't feel good. That's embarrassing. But also I look at the kids, my kids and the kids that look up to me, and now I have to tell them why I did it. Maybe I can use this opportunity to let them know it's not worth it, point blank, period. It's just not worth it.”

Apparently, though, it's worth it to many players in the NFL. It seems clear that they're using HGH, and for now, it seems clear that there's little chance they'll be caught doing it.

Mike Freeman covers the NFL for Bleacher Report. Follow him on Twitter @mikefreemanNFL.