The Guardian Cap helmet covers worn by NFL players are not the same product sold to high school football programs across Massachusetts.

A MassLive investigation published Tuesday, Sept. 8, found the Guardian Cap XT, which retails at $89.99 and weighs 7 ounces, is a different product from the 14-ounce NXT model worn by New England Patriots players at training camp. Peachtree Corners, Georgia-based Guardian Sports estimates roughly 500,000 XT units are in circulation.

A 2024 Virginia Tech Helmet Lab study found that when two helmets equipped with the XT collide, rotational acceleration drops just 2%. The NXT reduced it by 12%. Concussion risk fell 22% with the XT and 63% with the NXT.

"Nobody is buying this cap and wearing it thinking that best case scenario, the benefit is a 2 percent reduction in the rotational acceleration," Christopher Nowinski, co-founder of the Boston University CTE Center, told MassLive. He said rotational acceleration is most closely linked to chronic traumatic encephalopathy (CTE), the degenerative brain disease found in football players.

Guardian Sports CEO Erin Hanson told MassLive the company has never claimed the XT reduces concussions, saying the product targets cumulative impact reduction over a player's career. She said the heavier NXT is not sold directly because she does not want parents putting 14 ounces on a young child's developing neck.

The Massachusetts Interscholastic Athletic Association (MIAA) has not mandated Guardian Caps for practice or games. Several Massachusetts programs use them voluntarily, including Xaverian Brothers, Weston, Wellesley, Swampscott and Marblehead, according to a Boston Globe editorial published Sept. 6. At Xaverian Brothers in Westwood, more than 75% of players wear the caps, CBS Boston reported Aug. 25.

No public reporting confirms whether Newton North, coached by Nick Capodilupo, or Newton South use Guardian Caps. Both programs compete in the Bay State Conference, where football sign-ups statewide have dropped 17% over the last 15 years.

Milton High School coach Steve Dembowski purchased 20 XT caps with booster funds in 2022 and requires linemen to wear them at practice. In more than four years of use, he told MassLive, no player has chosen to wear one on game day.