Why Don't We See More Guardian Caps During NFL Games?

Football season is in full swing, and even if you're not a fan, you've likely overheard office chatter about certain players or caught the post-game scores while skimming the news. Though the latest conversation swirling in the NFL is about how players can better protect themselves from concussions using something called a Guardian Cap.

This over-the-helmet cover is designed to reduce the impact of hits to the head. But rarely do you see players wearing on game night, though they are mandated for practices. The caps are in the headlines this week after Miami Dolphins quarterback, Tua Tagovailoa, stated that he will not be wearing a Guardian Cap this season, despite suffering multiple concussions in the last two years.

Tagovailoa was diagnosed with three concussions in the 2022 season, and he sustained a fourth concussion on September 12. He announced in a press conference on Monday that he has had no symptoms since then, has been cleared by doctors to resume practice, and hopes to play in Sunday's game against the Arizona Cardinals after passing the NFL's concussion protocol.

When asked if he would be wearing a guardian cap this season, Tagovailoa had a simple answer: "Nope," and cited "personal choice" — a decision that has shocked many fans. So what are Guardian Caps, exactly, and why don't more players wear them during games?

Experts Featured in This Article:

Daniel H. Daneshvar, MD, PhD, is co-director of concussion recovery for Mass General Brigham Sports Medicine.

What Is a Guardian Cap?

Guardian Caps are soft, padded helmet covers that are worn over football helmets. The caps work by absorbing linear impact through the padding, and reduce rotational forces as well, because they're not statically fixed to the helmet, says Jake Hanson, the chief operating officer of Guardian Sports, which manufactures the Guardian Cap. According to Hanson, each cap weighs less than seven ounces, and one size fits all standard football helmets.

"The caps are meant to help reduce the impact forces during head collisions by absorbing impact force," says Daniel H. Daneshvar, M.D., Ph.D., co-director of concussion recovery for Mass General Brigham Sports Medicine. "They aim to provide additional protection against concussive and non-concussive hits."

Guardian caps were mandated during the 2023 season at every preseason practice, and this year, the NFL allowed players to wear them during regular season games. Still, many players opt out of wearing them.

How Effective Are Guardian Caps?

"While no helmet or aftermarket add-on can prevent or eliminate the risk of concussions and other serious head injuries," Hanson says, "The Guardian Cap has been found to reduce HARM (short for head acceleration response metric, which is used to measure the severity of head impacts and the efficacy of protective gear) by up to 40 percent."

When the league tested Guardian Caps in the 2022 football preseason, groups required to wear the caps saw an over 50 percent reduction in concussions, compared to the previous three-year average (excluding 2020). However, Dr. Daneshvar notes that this could be for multiple possible reasons, as the studies have not yet been independently reviewed and published.

The NFL and NFL-affiliated researchers have also reported that Guardian Caps absorb about 10 percent of the force during a collision in lab settings if one player is wearing the cap, and 20 percent if all players involved are wearing them. Dr. Daneshvar explains: "Given that an average concussion occurs at around 80 [g-force], this means a cap (worn by a single player) would decrease an average concussive impact to around 72g." For reference, according to a 2004 study that evaluated concussion data from the NFL suggests that a 98g acceleration puts the athlete at a 75 percent risk of injury.

Guardian Caps clearly help reduce the risk of concussions from head-on collisions. A comprehensive scientific review has shown that repetitive head impacts in football can be followed by changes in cognitive function in the brain, and more than 300 former NFL players have been posthumously diagnosed with chronic traumatic encephalopathy, better known as CTE.

So Why Don't More Athletes Wear Guardian Caps?

"The Guardian Cap is worn by over 500,000 football athletes, but primarily in practice," says Hanson. "As for games, football players, coaches, and fans are all creatures of habit, and any change in any aspect of the game is going to result in some criticism."

Dr. Daneshvar adds that there have been some concerns about potential changes in how the caps might alter player technique, and many have concerns about comfort and fit, combined with the perception of added weight or bulk. Additionally, he says some are still skeptical about the Guardian Caps's effectiveness in preventing concussions.

Still, seven players have been already been spotted wearing Guardian Caps this season, according to Guardian Sports. "I can't mess around anymore. I want to stay healthy, and if this is what it takes, then I'm all for it," said Josh Whyle, a tight end for the Tennessee Titans in an interview with ESPN.

Kaley Rohlinger is a freelance writer for PS who focuses on health, fitness, food, and lifestyle content. She has a background in the marketing and communications industry and has written for PS for over four years.