The only thing weirder than men in suits selling weed soda at a pot conference is NFL players mingling among them.

Such was the scene at the Cannabis World Congress this week in New York City, where more than 75 businesses, non-profits, and drug policy activists gathered to stake their claim in the future of pot. The third conference of its kind, the event was equal parts serious and silly—like an indoor church festival planned by rich stoners.

There were hipsters with cannabis-infused juice, a Canadian pushing hemp dog treats, and a hippie spraying liquid THC from a pink bottle. There were men in white lab coats, a poodle named Tobias, and a man in a jumpsuit with a bunny called “Potter.” In side rooms, leaders hosted seminars with titles like “From Goldfish to Blackfish: How Entrepreneurs Thrive in a Sea of Competition.”

But among all the businessmen, policy wonks, doctors, and volunteers it was the colossal men in button-downs who stole the show—former NFL and NHL players coming to share their cannabis stories. Unlike earlier seminars, where less than a dozen participants gathered in large rooms, the sports panel the players hosted was packed to the gills.

Cameramen crowded in the back, fans took seats in the front, reporters sat scribbling notes.

The subject of the talk: chronic traumatic encephalopathy (CTE), a deterioration of the brain caused by repeated trauma to the head. Captured in a documentary by Frontline and a movie starring Will Smith called Concussion, the degenerative disease was initially thought to be a boxing injury only.

But after studying the brain of former Pittsburgh Steeler’s center Mike Webster, Bennett Omalu penned a groundbreaking study revealing that football players—who endure years of head trauma—are at risk too. Among the disease’s side effects: memory loss, aggression, severe depression, anxiety, suicidal thoughts, and progressive dementia.

In September, researchers from Boston University and the Department of Veterans Affairs released a report announcing that 96 percent of the brains of deceased pro-football players they studied have shown signs of CTE. Leonard Marshall, a former lineman for the New York Giants who opened the panel, says he’s suffered symptoms of CTE himself.

The winner of two Super Bowls explained how the use of cannabis has helped him overcome some of the symptoms associated with the disease—and argued that ganjapreneurs should take note.

“I hope the message this afternoon about the use of cannabinoids and how it has affected our lives, I hope that you share it,” he told the crowd. “My quality of life has improved because of this. My quality of life has improved because I’ve adopted the mentality that I’d rather live than die.”

Marshall said he knew that the constant trauma to his head was dangerous, but thought that the he was adequately protected. “Wearing a helmet made you feel indestructible,” he said. “While playing with this helmet, you’re kind of a gladiator and this is your tool.” Playing from the mid-1980s to 1990s, he existed in a time when the dangers of tackling were either unknown or ignored.

“Coaches taught players back in my era to utilize this [weapon] just as such. To maim a player, to injure a player, to intimidate a player,” he said. “This was your sword. Your sword as a gladiator.” Had he known how much damage this type of play would cause to his brain, Marshall said he wouldn’t have taken the “journey” the way he did.

Now that he’s suffering the effects of CTE, like many of his fellow players, he’s found marijuana to be a life-saving remedy. “I hope that what comes out of this conference is a true testament to what [the players] have endured,” he said. “… and that cannabinoids now play a major role in their lives in terms of total wellness.”

After Marshall finished speaking, former NFL and NHL players took the stage to share their personal stories and answer questions from the crowd. Among them were former Jacksonville Jaguars offensive lineman Eben Britton, former Denver Broncos tight end Nate Jackson, and former Chicago Bears quarterback Jim McMahon.

All are members of the Gridiron Cannabis Coalition, a group of players dedicated to the advancement of medical marijuana research. “The sport of American Football is plagued with multiple ailments and diseases currently void of non-addictive treatments and cures, the website reads. “The GCC is determined to resolve this impasse to allow players and the public option of an organic treatment for injury and illness through Cannabis.”

Beyond helping neutralize the effects of CTE, many players have reported that cannabis is helpful in treating the chronic pain they suffer after retiring. The first line of treatment for chronic pain in the NFL—and nationwide—is painkillers, which Marshall and the other players have seen ruin lives.

“I watched a former teammate of mine in New Jersey go from a sensitive tender guy to a guy who was popping 1500 painkillers a month to live,” said Marshall. Adding later: “Had I known what I know now about cannabinoids, I probably would have shared this with him.”

McMahon has experienced the dangers of opioids first hand, and has since found cannabis to be a safer substitute. In January he told the Chicago Tribune that the marijuana got him off the pills. “They were doing more harm than good,” he told them. “This medical marijuana has been a godsend. It relieves me of the pain—or thinking about it, anyway.”

While the federal ban on marijuana has made studying it on humans near impossible, preliminary research on its medical benefits has shown it effective in treating chronic pain and depression (among other things). Like any drug, it comes with side effects that must be taken into consideration, such as dizziness and short-term memory loss.

For players like Marshall, who endured long-term trauma to the brain, it’s a small price to pay.