January 20, 2025
Throughout the NFL season and now the playoffs, I’ve noticed an occasional player wearing what appears to be an oversized helmet. When I did a quick internet search, I found that these were “Guardian Caps,” padded helmet covers that football players can use to protect themselves from brain injuries. Do they work?
Dr. Pardo Prescribes
The caps, produced by Guardian Sports, add a layer of foam to the outside of the helmet. The idea, says the company on its website, is that the “lightweight external soft cover … augments any existing helmet to make it flexible and soft, able to more effectively manage energy and mitigate repetitive, cumulative blows.”
Football has been shown to pose a series of interrelated risks to the brain, most often caused by blows to the head. There are the well-publicized concussions, mild traumatic brain injuries that typically come with symptoms like headache, confusion and inability to concentrate, with symptoms usually resolving over a course of days.
This is a detailed view of the Guardian Cap worn by Los Angeles Rams guard Kevin Dotson (69) on Dec. 1 against the New Orleans Saints during the second half at Caesars Superdome.
Players also experience sub-concussive blows, lesser impacts that don’t cause clinical symptoms but can still cause damage to brain cells, blood vessels and the brain’s protective barrier. Over time, the accumulation of both types of brain injuries can cause chronic traumatic encephalopathy, or CTE, a progressive and fatal brain disease with symptoms similar to Alzheimer’s.
In an effort to protect players, the NFL mandated the use of Guardian Caps during training camp and practices involving contact, and in an interview, a league official said those who wore them had more than a 50% reduction in concussions. However, review of the scientific literature revealed no peer-reviewed research that would support their use.
A Guardian Cap, an extra soft-shell pad worn over players’ helmets that was designed to decrease the amount of force received from head contact, is pictured June 9, 2022, at the Pittsburgh Steelers minicamp at UPMC Rooney Sports Complex.
A 2017 study that looked only at the helmets’ ability to withstand blows — and didn’t involve any human subjects — found that the caps failed to significantly reduce impact in most situations.
More recently, a 2023 study out of Stanford University looked at the caps in both a laboratory setting and while worn by players during practice. In each context, the scientists found little evidence that the devices offered meaningful protection.
These results are not surprising, as both concussions and sub-concussive injuries are caused when a blow to the head causes the brain to move rapidly within the skull. An extra layer on a helmet cannot prevent that.
To protect against these brain injuries, you’d need to reduce the force of the impact itself, which would entail things like tackling more gently. And anyone who’s watched football understands this isn’t a change in the game we’re likely to see soon.