--- title: At Least One in Four NFL Players May Have CTE description: A new study on donated brain tissue from former football players found troubling signs of CTE, a degenerative brain disease. canonical: https://time.com/article/2026/08/27/one-in-four-nfl-football-players-may-have-cte/ author: Jeffrey Kluger article:opinion: false article:content_tier: free article:published_time: 2026-08-27T14:29:06.448Z article:modified_time: 2026-08-27T14:29:06.652Z article:section: Health og:title: At Least One in Four NFL Players May Have CTE og:description: A new study on donated brain tissue from former football players found troubling signs of CTE, a degenerative brain disease. og:url: https://time.com/article/2026/08/27/one-in-four-nfl-football-players-may-have-cte/ og:site_name: TIME og:image: https://static.time.com/v3/assets/bltea6093859af6183b/bltdd0924f189ec4a71/6a8f1d8b24fd12a0fda8a33d/GettyImages-1191212958.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 og:image:width: 3000 og:image:height: 1688 og:image:alt: GettyImages-1191212958.jpg og:type: article twitter:card: summary_large_image twitter:title: At Least One in Four NFL Players May Have CTE twitter:description: A new study on donated brain tissue from former football players found troubling signs of CTE, a degenerative brain disease. twitter:image: https://static.time.com/v3/assets/bltea6093859af6183b/bltdd0924f189ec4a71/6a8f1d8b24fd12a0fda8a33d/GettyImages-1191212958.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 ---  # At Least One in Four NFL Players May Have CTE  by [Jeffrey Kluger](https://time.com/author/jeffrey-kluger/)  ## Jeffrey Kluger Editor at Large Aug 27, 2026 2:29 PM UTC  Helmet-to-helmet hits are now banned in the NFL. Helmet-to-helmet hits are now banned in the NFL.George Gojkovich—Getty Images  by [Jeffrey Kluger](https://time.com/author/jeffrey-kluger/)  ## Jeffrey Kluger Editor at Large Aug 27, 2026 2:29 PM UTC An alarming number of professional football players in the U.S. may someday have [chronic traumatic encephalopathy (CTE)](https://time.com/7306793/what-is-cte-new-york-shooting/), the neurodegenerative disease associated with repeated concussions and sub-concussive hits to the head, [a new study](http://dx.doi.org/10.1136/bmj-2026-100418) suggests. The research, published in the _BMJ_, studied the brains of NFL players who died from 2016 to 2021 and found that one in four had CTE—a figure that is almost certainly an undercount, the researchers say. Depending on how they crunched the numbers, the CTE incidence rose as high as 91%. “The one in four figure is intentionally the most conservative estimate possible,” says lead author Dr. Daniel Daneshvar, chair of the department of physical medicine and rehabilitation at Mass General Brigham and associate professor at Harvard Medical School. “We know the true prevalence is higher than that.” It was in 1928 that pathologist Harrison Martland [first described](https://concussionandcte.org/cte-resources/what-is-cte/) the condition now known as CTE in boxers experiencing what he called “punch drunk” syndrome. It was not until 2002 that the disease was first diagnosed in an NFL player, [when neuropathologist Bennet I. Omalu](https://www.ama-assn.org/public-health/injury-violence-prevention/physician-who-discovered-cte-nfl-players-gets-ama-s) examined the brain of Mike Webster, a former player for the Pittsburgh Steelers, and found [the buildup of tau proteins](https://www.mayoclinic.org/diseases-conditions/chronic-traumatic-encephalopathy/symptoms-causes/syc-20370921) around blood vessels, thinning of tissue, and overall brain atrophy that characterize the disease. CTE is only firmly diagnosable by autopsy, but the range of symptoms that point to the disease—including memory loss, confusion, aggression, depression, apathy, tremors, and slurred speech—can be pronounced during a person’s life. “Many of these former players had dementia,” says Daneshvar, “meaning their cognitive symptoms were severe enough to interfere with their ability to function independently. These are not just microscopic changes that we happen to find when someone dies. We are talking about a disease that can profoundly affect people’s ability to think, work, maintain relationships, and live independently.” ## What the research found In the new study, Daneshvar and his colleagues examined the brains of 235 former NFL players who had donated their brains to science. (A total of 878 players died in that 2016-2021 window.) Of the brains studied, 215 were found to have CTE—or 91%. The researchers arrived at their much lower one-in-four figure by making the exceedingly cautious assumption that none of the remaining 643 brains would have shown signs of the disease—an assumption that Daneshvar believes would not stand up if the brains had been examined. “Among the people who did not donate,” he says, “16% had dementia listed on their death certificate. That certainly does not mean they had CTE, but it illustrates how unrealistic it is to assume that every non-donor was disease-free.” Another part of the study looked at a larger time window—from 2008 to 2021—during which 1,712 former NFL players died. Of those, 338, including the 235 already analyzed, donated their brains to research, and of that group, 315 had CTE. That makes for a possible CTE prevalence of as high as 93.2%, though if the researchers once again made the conservative—if unrealistic—estimate that all of the unexamined brains were disease-free, the figure would drop to 18.4%. ## How to make football safer What makes CTE particularly insidious is that it is a cumulative disease, one that builds up over a career’s-worth of hits that don’t begin when a player is tapped for the NFL, but can stretch back into college, high school, and even childhood play. In 2011, the NFL, mindful of the growing incidence of CTE, established its [concussion protocol](https://www.nfl.com/playerhealthandsafety/health-and-wellness/player-care/concussion-protocol-return-to-participation-protocol), sidelining players who take a hit and exhibit any signs of possible concussion, such as confusion, amnesia, ataxia—a lack of muscle control—or any loss of consciousness. That’s a big improvement over the days when concussed players were simply described as having had their “bell rung,” and then sent back out onto the field to continue the game. But concussions are only the most extreme symptoms of brain trauma; there’s a lot of damage that’s done invisibly, with no signs at all. According to [one 2012 study](https://pubmed.ncbi.nlm.nih.gov/21994067/) in the _Annals of Biomedical Engineering_, a college football player may sustain up to 1,000 subconcussive hits to the head over the course of a single season of play. “Concussion protocols are important,” says Daneshvar, “but concussion management and CTE prevention are not the same thing. The evidence increasingly suggests that CTE risk is related to cumulative exposure to repetitive head impacts, including the many impacts that never cause a diagnosed concussion. A player can follow every concussion protocol appropriately and still accumulate thousands of head impacts over a year.” In addition to the concussion protocols, the NFL has made other rule changes to reduce the incidence of brain trauma, including [outlawing both helmet-to-helmet hits](https://www.nfl.com/news/nfl-expands-rule-against-misuse-of-helmet-guardian-caps-required-in-regular-seas) and [so-called blindside blocks](https://www.nfl.com/playerhealthandsafety/equipment-and-innovation/rules-changes/nfl-health-and-safety-related-rules-changes-since-2002), in which an unsuspecting player is struck from behind, often leading to head and neck injuries. Bigger changes could come during practice, when 70% of hits occur, Daneshvar says. These friendly collisions, he adds, do as much cerebral damage as actual blows sustained during a game. “The NFL has already moved dramatically in this direction,” he says. “NFL players now have less than one full-contact practice per week.” Another concern is that measures like this may be coming too late, since young players may be reaching the NFL having sustained brain damage already. Former New England Patriots player Aaron Hernandez, for example, was only 27 when he died by suicide while serving a life sentence for murder. He had spent just four years in the NFL and he was posthumously diagnosed with [the worst case](https://www.bu.edu/articles/2017/aaron-hernandez-cte-worst-seen-in-young-person/) of CTE that Boston University researchers had ever seen in a person his age. “We don’t need to eliminate football to make it substantially safer,” says Daneshvar—but just like in the pros, high school and college football programs could be changed to minimize or eliminate collisions in practice, and to outlaw hits during games that could be exacerbating trauma to the brain. ```json [{"@context":"https://schema.org","@type":"NewsArticle","@id":"https://time.com/article/2026/08/27/one-in-four-nfl-football-players-may-have-cte/","mainEntityOfPage":{"@type":"WebPage","@id":"https://time.com/article/2026/08/27/one-in-four-nfl-football-players-may-have-cte/"},"headline":"At Least One in Four NFL Players May Have CTE","datePublished":"2026-08-27T14:29:06.448Z","dateModified":"2026-08-27T14:29:06.652Z","description":"A new study on donated brain tissue from former football players found troubling signs of CTE, a degenerative brain disease.","url":"https://time.com/article/2026/08/27/one-in-four-nfl-football-players-may-have-cte/","keywords":["Brain"],"thumbnailUrl":"https://static.time.com/v3/assets/bltea6093859af6183b/bltdd0924f189ec4a71/6a8f1d8b24fd12a0fda8a33d/GettyImages-1191212958.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","author":[{"@type":"Person","name":"Jeffrey Kluger","jobTitle":"Editor at Large","url":"https://time.com/author/jeffrey-kluger/"}],"articleSection":"Health","image":[{"@type":"ImageObject","url":"https://static.time.com/v3/assets/bltea6093859af6183b/bltdd0924f189ec4a71/6a8f1d8b24fd12a0fda8a33d/GettyImages-1191212958.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","width":1200,"height":675,"headline":"GettyImages-1191212958.jpg","caption":"","creditText":"George Gojkovich—Getty Images","representativeOfPage":true}],"publisher":{"@type":"Organization","name":"Time","url":"https://time.com/","logo":{"@type":"ImageObject","url":"https://time.com/images/logo.png","width":528,"height":156},"foundingDate":"March 3, 1923","sameAs":["https://www.facebook.com/time","https://www.instagram.com/time/?hl=en","https://twitter.com/time","https://www.pinterest.com/timemagazine"]}},{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/section/health/","name":"Health"}},{"@type":"ListItem","position":2,"item":{"@id":"/tag/brain/","name":"Brain"}},{"@type":"ListItem","position":3,"item":{"@id":"https://time.com/article/2026/08/27/one-in-four-nfl-football-players-may-have-cte/","name":"At Least One in Four NFL Players May Have CTE"}}]}] ```