A $20 mouthguard for weightlifting might add a few pounds to your squat. And save a $1 000 dental bill.
Key Points:
- Wearing a well-fitted mouthguard can boost muscle power in the gym.
- Custom mouthguards work best, while cheap stock ones may reduce performance.
- For best results, use the guard on heavy sets, clench hard, keep it clean, and replace it regularly.
In this article, you’ll learn why a mouthguard does more than protect your teeth from grinding and if it’s a good idea to pop one in before grinding new PRs in the gym.
Table of Contents
What Is a Mouthguard for Weightlifting?
A weightlifting mouthguard is a piece of (usually) pliable material that you pop in your mouth to give your teeth a cushion during a lift.
It creates a protective barrier so you can clench down without turning your molars to dust.
Mouthguards are becoming increasingly more common in sports, and they aren’t just for boxers or hockey players who are worried about taking a puck to the kisser.
I remember the first time I saw someone wearing a mouthpiece in the gym. It was back in the 1990s, and a fellow lifter had popped in a boxer’s mouthpiece.
Using mouthguards while lifting back then wasn’t unheard of, but most people did it to protect their teeth. However, this guy did it because he felt he could exert himself more during heavy lifts with this little piece of plastic in his mouth.
Turns out, he was onto something. Today, more and more lifters are getting in on the action for a number of good reasons, with the science to back them up.
The Research Behind Jaw Clenching During Lifts
A growing number of studies, plus several systematic reviews, show small-to-moderate improvements in strength or power.
In lab tests, lifters clenching hard on a well-fitted, “performance” mouthguard squeezed out:
- A couple of % more muscle power and isokinetic strength
- Faster rate of force development (you hit top force sooner; great for squats out of the hole)
- Up to 40% lower post-session cortisol, which suggests easier recovery
Those numbers won’t turn your 350 lb back squat into 400 lb overnight, but they do mean a few extra pounds on the bar or one more rep, which might translate into small but meaningful gains over time.
But the picture is mixed, with a few studies finding no benefit at all or even a slight negative effect.
What the Systematic Reviews Say
Systematic reviews and meta-analyses pool the results of many studies and reach conclusions that carry more weight than any single study.
Here’s what three systematic reviews published since 2021 found.
2021 Review
A big review from 2021 sifted through over 4,000 studies. The researchers found 27 high-quality trials and a clear trend: athletes improved lower-body power and knee extension strength when they wore a mouthpiece.1
The gains were especially apparent when they used a custom-fitted mouthguard and were told to bite down hard during the effort.
2023 Review
Fast-forward to 2023, and the Journal of Science & Medicine in Sport took another look at athletic performance with or without mouthguards, covering 40 studies and 852 athletes.2
Their conclusion was that using a mouthguard “shows potential improvements of athletic performance” in dynamic and maximal strength, power, and isometric and peak force.
They did point out that the studies were all over the place in terms of the types of mouthguards used and how they were tested, making it hard to draw clear conclusions.
2025 Review
The most recent big-picture look, a review from the Dentistry Journal in 2025, found varying results.3
Some studies showed performance improvements:
- More balance stability
- Better-balanced force production
- Increased shoulder strength and muscle activation
Other studies, however, reported no significant effects.
Some studies show small but significant improvements in strength, power, and performance from using a mouthguard.
Typical effect sizes range from ~1–4% in peak force/power. That can mean the winning edge for competitive athletes but won’t be a make-or-break factor for casual lifters.
Some studies show no effect at all or even a performance decrease.
How a Mouthguard for Weightlifting Improves Performance
Here’s what happens inside your body when you bite down hard and why doing so can give you a burst of extra strength or power.
| # | What happens | Why it can help you perform better |
|---|---|---|
| 1 | When you clench your jaw, you activate the part of your brain that controls motor functions. That activation spills over to other neural centers in the brain, sending signals to the muscles you’re about to use. | More fibers in the working muscles receive a clear “go now!” signal and can contract faster and harder. |
| 2 | Clamping your teeth boosts the activity of spinal motor neurons and the little feedback loops that help them. | A louder signal from the spine = bigger, quicker impulses to your working muscles = more force and a higher rate of force development. |
| 3 | Clenching strengthens a stretch reflex called the Hoffman reflex. The harder you bite, the more you prime this reflex. | A stronger Hoffman reflex lets your muscles rebound with more explosiveness during a lift or a jump. |
| 4 | Biting on a mouthguard nudges your jaw into a balanced position and re-aligns muscles that support your head, neck and spine. | You waste less tension and allow your muscles to fire in a more efficient line. |
| 5 | Pressure on the teeth and gums pours information into the trigeminal nerve, a sensory highway to the brain. | Your brain gets a clearer picture of your body position and can fine-tune your movements and improve coordination. |
All of these effects together are called concurrent activation potentiation or CAP. It’s like squeezing the bar before a deadlift: a remote contraction that primes your nervous system.
Without a mouthguard, your body flips a safety switch and prevents you from clenching with maximum force to protect your teeth.
And the more snug the mouthguard, the better you distribute the clenching forces for a more powerful effect.
A mouthguard provides a stable platform that allows you to clench with full power, sending signals through your brain and spine to give a boost to the muscles involved.
The Different Flavors of Mouthguards
You’ve got a few options when it comes to picking out a mouthguard for weightlifting.
Here are the ones used in sports research:
Custom-Fit Mouthguards
This is the top-of-the-line option, custom-scanned, precision-trimmed, and designed for your jaw. A dentist takes an impression of your teeth, and a lab creates a mouthguard that fits you perfectly.
Custom-made mouthguards are the most comfortable and offer the best protection and the most reliable performance benefits, but they’re also the priciest.
Boil and Bite Mouthguards
This is the most popular type of mouthguard for athletes. You boil it in water to make it soft and then bite down to create a custom-ish mold of your teeth.
They fit much better than most stock guards and are still relatively inexpensive. However, any performance benefits rely on you getting the molding perfect.
Stock “One-Size” Mouthguards
This is the cheapest and most basic option. You can find them at most sporting goods stores.
Stock mouthguards are a one-size-fits-most deal, which usually means they don’t fit anyone particularly well and can pop out mid-set.
They might be better than nothing, but not by much, at least not for gym performance.
Pro tip: whichever type you pick, remold or refit the mouthguard until the bite feels even side-to-side. An asymmetrical guard can reduce force output and annoy your temporomandibular joint, which connects your jawbone to the skull.
Almost every positive trial used either dentist-molded splints or mouthguards that lock your mandible into a “power” position.
Stock mouthguards and the cheapest “boil and bite” one you can grab at the sporting goods store are better than nothing for protecting your teeth.
They are probably not going to do much for your performance, though. At least nothing good. The worst ones might even reduce it.
Studies that showed the biggest performance benefits use custom-fitted guards.
Practical Mouthguard Tips for Gym Use
Here are five practical and actionable tips for using your mouthguard and keeping it in tip-top shape.
Clench With Intent
The guard is a conduit, so you want to bite down as hard as you can.
It can be a good idea to warm up with your mouthguard to get used to the feel of it before you reach your top sets, but bite hard only on money reps. Constant clenching during light sets does nothing but fatigue your jaw.
Clean It Daily
A 2025 survey data shows that less than 40% of athletes clean their guards properly, and bacteria colonies can explode after a week of neglect.4
After using your mouthguard, do a quick rinse and brush it with a toothbrush, then let it air-dry in a ventilated case.
Once a week, soak it in 3% hydrogen peroxide for 10 minutes to kill lingering bacteria.
These are guidelines from the American Dental Association and work well with your performance mouthguard as well.5
Replace It Once A Year Or So
Mouthguards don’t last forever. Replace it every 6–12 months or sooner if the plastic deforms.
High-quality custom-fit guards last longer than off-the-shelf ones you boil to fit.
Weigh Comfort & Breathing
If the device feels bulky or restricts your air flow, any theoretical performance benefits will vanish like a genie into thin air.
Fit Matters Most
Have a dentist or sports dentist fabricate a guard that sets your bite in a slightly forward/centered “power” position.
Yes, it costs more, but off-the-rack or boil-and-bite models rarely have any ergogenic effects in studies.
Frequently Asked Questions About Using A Mouthguard
It protects your teeth, can ease jaw or TMJ strain during heavy reps, and might improve performance.
No. Expect single-digit percentage bumps at best, not miracles.
No, powerlifters, CrossFitters, strongman athletes, and regular gym-goers wear them for both performance and dental bills.
Custom dental guard: best fit and performance boosts, but pricey.
Boil-and-bite: good budget pick if you fit it properly.
Stock: cheapest, but often fails to improve performance and can slip.
Heat-mold (per the packet), cool to set, then rinse and brush after every session. Air-dry in a vented case.
As soon as it cracks, loosens, or smells: typically every 6–12 months for most lifters.
Final Rep
Is a mouthguard an essential piece of weightlifting gear? Maybe not for everyone.
But if you’re a lifter who tends to grind your teeth, it’s something to consider.
It might improve your performance in the gym a bit, at least as long as you invest in a quality, well-fitted strength-training mouthguard.
Important note: Any claims that a mouthguard for weightlifting will make huge changes for the better are marketing spins. There is no evidence for anything like double-digit performance increases in strength, power, or force, as some ads say.
At the very least, it’ll save you from explaining to your dentist how you managed to chip a tooth while doing a PB in the squat. And that’s a conversation worth avoiding. For your wallet, if nothing else.
Last reviewed: 2026-01-05
References
- Int J Environ Res Public Health. 2021 Jun 28;18(13):6933. Acute Effects of Wearing Bite-Aligning Mouthguards on Muscular Strength, Power, Agility and Quickness in a Trained Population: A Systematic Review.
- J Sci Med Sport. 2023 Sep;26(9):493-503. Influence of wearing mouthguards on performance among athletes: A systematic review.
- Dent J (Basel). 2025 Apr 18;13(4):170. Dental Splints and Sport Performance: A Review of the Current Literature.
- PLoS One. 2025 Jan 29;20(1):e0317952. Mouthguard use, hygiene, and maintenance practices among combat and team sports athletes: A comparative study.
- The Journal of the American Dental Association, Volume 148, Issue 6, 476. Keeping your teeth and mouth safe.
