As the long-term consequences of concussions become clearer, a cottage industry has popped up to sell athletes and worried parents products designed to mitigate risks of concussions that even helmets cannot prevent.
Despite the bold claims of some companies, however, many experts say the Holy Grail in contact sports -- a device that prevents concussions -- simply does not exist. Indeed, experts say, there is no proof that any current device significantly reduces the risk of concussions beyond the protections already provided by helmets.
"Nightline" found several products for sale online that aim to reduce the risk of concussions or even alert parents and coaches when a kid has supposedly taken a concussion-level hit. The claims the manufacturers make are often breathtakingly reassuring.
Concern about the risk of concussion is mounting at every level of the gridiron from the NFL to colleges and even high schools. Concussions are the most common injury among high school football players.
Jennifer Branin, whose son Tyler Branin is one of the stars of the Woodbridge Warriors high school football team in Irvine, Calif., said "it was scary" the first time he had a concussion.
"He had lost his balance on the field," she said. "He got up and tried to continue, but couldn't keep his balance."
She said the effects of the concussion lingered, causing Tyler to miss a week of school and football practice. Even months later, he complained of difficulty concentrating in class.
Parents such as Jennifer Branin, who is president of the team's booster club, and her husband, Andy Branin, a former college football player himself, were looking for a way to support their son's desire to play football while also keeping him safe.
"He wants to play and, as a mom, you may want to put bubble-wrap around them and protect them forever, but that's not going to happen," she said.
So Jennifer Branin decided to do something. She raised money to buy the team helmet inserts by Unequal Technologies for added protection.
Unequal Technologies, one of the highest profile players in this new market, described its product explicitly on the box as "Concussion Reduction Technology," or "CRT." It is a strip of composite material including bullet-proof Kevlar that is designed to stick inside the helmet as a liner to the existing helmet pads.
Unequal Technologies uses its material in products ranging from padded sleeves to shin guards. The company counts NFL players and X-Games athletes among its fans.
On board as paid spokesmen are Philadelphia Eagles quarterback Michael Vick and James Harrison, a linebacker for the Pittsburgh Steelers. Harrison is one of the hardest-hitting guys in the NFL and said he uses Unequal Technology's liners in his helmet.
"I don't know what it's made of but it works," Harrison says in one of Unequal's promotional videos. "I really don't feel like I'm taking a risk."
Vick wasn't wearing the CRT product when he suffered a season-ending concussion in November, but he has since promised that he will be wearing it when he returns to the field next season.
Rob Vito, founder and CEO of the Kennett Square, Pa.-based company, said he worked with scientists to create a military-grade composite material that can help protect athletes from all kinds of injuries from head to toe.
Unequal Technologies' product tests were conducted at the Southern Impact Research Center in Rockford, Tenn., one of the nation's leading testing labs for sports equipment. Engineer Dave Halstead, the lab's technical director, said it's important to understand that helmets have come a long way in keeping players safe from a certain kind of head injury, the kind caused by direct, linear force.
But when asked if there was a device or an add-on currently on the market that can fully protect players' from the risk of head injury, Halstead said "absolutely not."
"That magic bullet, that if you just do this you can continue to play the way you are and you're immune from injury, it just doesn't work," he said. "There is no such device."
The modern helmet already offers excellent protection against direct hits, which produce sharp, linear forces against the skull.
But many doctors believe sports-induced concussions are caused by shearing, rotational forces, which occur when the head snaps back and swerves around on the neck, slamming the brain against the inside of the skull.
There is no proof that products like Unequal Technologies' strips protect against those injuries -- the ones suspected of frequently causing concussions.
Halstead's testing did show that the Unequal strips can reduce the severity of a linear, direct impact from some angles, but not from others. But even Vito acknowledged he cannot prove those results reduce the risk of concussions.
"No, we can't make that claim at this point, it's too early on," he said.
But Vito said his company only claims to "help reduce the possibility of head injury," adding, "We never mention the word 'concussion,'" although the product's name is "Concussion Reduction Technology."
"There might be some confusion," Vito acknowledged, maintaining that his company is not claiming its product reduce concussions, saying, "One is a name and one is a claim and our claim is that we help reduce the possibility of head injury."
After the ABC News interview, Unequal Technologies sent "Nightline" what it said would be the new packaging for its product, which says just "CRT" now, The words "Concussion Reduction Technology" have been removed.