Do Guardian Caps Really Protect Against Concussions?

What the Newest Helmet Research and DHA Science Reveal About Brain Safety in Football

During Week 7's Monday Night Football game, Tampa Bay wide receiver Mike Evans left the game after his head hit the ground while making a catch.
He was ruled out with both a shoulder injury and a concussion.

Moments like this remind us that concussions do not always come from helmet-to-helmet collisions. Sometimes, the ground is the hardest opponent on the field.

That moment raised a larger question:
Are we truly doing enough to protect players’ brains?

The Rise of Guardian Caps

Those padded shells worn over helmets during practices are called Guardian Caps.
The NFL began requiring them during preseason and certain position group practices, claiming in 2022 that teams using Guardian Caps saw a 50 percent reduction in concussions.

However, there was no peer-reviewed research supporting that number.
The claim was based on self-reported concussions, not measured impact data.

That is why a recent study caught the attention of researchers and coaches across the country.

The 2025 Guardian Cap Study

Researchers from the University of Georgia and the University of North Carolina published the first large-scale, field-based study on Guardian Caps in Medicine & Science in Sports & Exercise (2025).

Study Overview

• 53 college football players participated.

• 11 wore Guardian Caps during contact practices, but not games.

• Data were collected using instrumented mouthguards that measured real-time impact forces.

• In total, there were 7,509 recorded head impacts, with 1,379 occurring while players wore Guardian Caps.

This provided the most detailed on-field dataset ever collected for Guardian Cap use.

Findings That Matter

1. No reduction in impact force or frequency.
   Wearing the Guardian Cap did not make hits softer or less frequent.

2. Impact location shifted.
   Players wearing Guardian Caps had 36 percent fewer hits to the facemask but 151 percent more hits to the back of the head.

3. Player behavior may be the variable.
   Researchers noted a possible risk compensation effect.
   This is the theory that when people feel safer, they take more risks.
   For example, when wearing a seatbelt, you might feel more confident driving faster.

   On the field, that could mean players are more willing to lead with their heads, thinking the Guardian Cap protects them more than it does.

The Takeaway

The Guardian Cap did not make impacts worse, but it did not lessen them either.
What may determine its true safety value is how players adapt their behavior when wearing it.

Researchers concluded that more large-scale, randomized trials are needed before any definitive claims can be made about the Guardian Cap’s role in concussion prevention.

In other words, this study raised more questions than it answered, but it gave us real-world data to start from.

The Internal Side of Protection: DHA and Brain Health

While external gear like helmets and Guardian Caps focus on physical impact, nutrition may be just as important in protecting the brain from the inside out.
One of the most promising nutrients in this area is docosahexaenoic acid (DHA), a long-chain omega-3 fatty acid found in fish and algae oil.

DHA is a major structural component of brain tissue.
It supports membrane integrity, reduces inflammation, and helps neurons recover from mechanical stress, which happens during repeated football impacts.

The First DHA Study: Texas Christian University (2016)

In 2016, Dr. Jonathan Oliver and colleagues at Texas Christian University studied 81 Division I football players over a full season.
Players received daily DHA doses of 2, 4, or 6 grams, or a placebo.

Researchers tracked neurofilament light (Nf-L), which is a structural protein found inside nerve fibers in the brain. When neurons are damaged, small amounts of this protein leak into the bloodstream. Higher blood levels of Nf-L mean more axonal stress or injury.

Scientists now use Nf-L as a biomarker of brain trauma to monitor subconcussive and concussive impacts in contact sports.
It allows researchers to detect microscopic brain injury long before symptoms appear.

Key Findings

• DHA supplementation significantly raised blood DHA levels.

• Players who took DHA had smaller increases in Nf-L, meaning less nerve damage.

• Even 2 grams per day made a measurable difference.

This was the first large human trial showing that DHA could help the brain resist the effects of repeated subconcussive impacts.

The Follow-Up Study: Multi-Site Trial (2021)

In 2021, Oliver and a multi-university team expanded the research with a study published in the Journal of the International Society of Sports Nutrition.
This time, researchers included two NCAA football teams — one that took omega-3 supplements and one that did not.

Supplement Formula

Each athlete in the treatment group received a combination of:

• 2,000 mg DHA

• 560 mg EPA

• 320 mg DPA

The supplement was given throughout the entire season.

Results

• Omega-3 supplementation increased DHA and EPA levels in the blood by over 100 percent.

• It improved the omega-3 index (a measure of cardiovascular and neurological health).

• Most importantly, it attenuated the rise in serum Nf-L, the biomarker of axonal injury, throughout the season.

Players who did not supplement showed sharp increases in Nf-L, especially starters who experienced more plays and higher contact volume.

Conclusion

This study reinforced what the 2016 trial found — that omega-3 fatty acids, especially DHA, can reduce markers of brain cell injury during a football season.
It also suggested cardiovascular benefits, helping offset the inflammation and oxidative stress common in football athletes.

What This Means for Player Safety

The combination of these studies paints a clearer picture:

• Guardian Caps may promote awareness, but have not yet proven to reduce impact severity.

• Omega-3 supplementation shows measurable, biological protection against internal brain stress and inflammation.

Taken together, these findings suggest that the future of concussion prevention may come from both sides of protection— the external armor of improved equipment and the internal armor provided by nutrition.

Our Perspective

At MaxWell Nutrition, we believe athlete safety starts with science.
That means understanding both mechanical and biological protection.

Our goal is to help athletes build stronger, healthier brains through evidence-based training and nutrition — from the inside out.

References

• Lynall, R. C., Sinnott, A. M., Van Dyke, C., Love, K. M., Schmidt, J. D., & Mihalik, J. P. (2025). Wearing a Guardian Cap Does Not Mitigate On-Field Head Impact Severity or Frequency in Collegiate Football. Medicine & Science in Sports & Exercise.

• Oliver, J. M., et al. (2016). Effect of Docosahexaenoic Acid on a Biomarker of Head Trauma in American Football.Medicine & Science in Sports & Exercise.

• Heileson, J. L., Anzalone, A. J., Carbuhn, A. F., et al. (2021). The Effect of Omega-3 Fatty Acids on a Biomarker of Head Trauma in NCAA Football Athletes: A Multi-Site, Non-Randomized Study. Journal of the International Society of Sports Nutrition, 18:65.