Jawline Exerciser: Do Jawline Exercise Tools Actually Work?
A jawline exerciser is a silicone ball, pad or mouthpiece you bite against to train your chewing muscles. It can make those muscles stronger, but there's no good evidence it makes your jawline look sharper. Jaw shape comes from bone, body fat and skin, and a bite tool changes none of them.
The short version:
What it trains: the masseter and other chewing muscles
What it doesn't change: bone structure, fat under the chin, skin
What the research shows: a two-person case report, and no controlled study on looks that we could find
Main risk: strain on the jaw joint (TMJ)
Below: what the studies actually say, how to read before-and-after photos, and what to know about safety before you buy one. If you want jaw workouts without a device, start with our guide to jawline exercises.
Not sure your jawline is even the weak spot? An attractiveness test shows how it compares with the rest of your face, before you spend money on a bite tool.
What Is a Jawline Exerciser?
A jawline exerciser (also called a jaw trainer or jawline exercise tool) is a small device, usually silicone, that you bite or chew against for resistance. Brands market it as a way to sculpt the jaw, but what it actually loads is the masseter and the other chewing muscles.
Types of jawline exercise tools
Type | How you use it | What to know |
|---|---|---|
Chew ball | Bite down on a silicone ball and release in sets | Jawzrsize is the best-known example; its resistance is listed at 20–40 lb (British Dental Journal) |
Molar pads or tabs | Clamp soft silicone pads between your back teeth | Chisell is one example; same idea, different shape |
Mouthpiece trainers | Bite into a mouthguard-style device, often with adjustable resistance | Sold under many brand names and price points |
All three work the same way: you clamp down against resistance, which trains the masseter (the thick muscle at the corner of your jaw) and the temporalis (the fan-shaped muscle at your temple). Neither muscle is bone or fat, and that matters for what a jawline exerciser can and can't do.
Do Jawline Exercisers Work?
Jawline exercisers can make your chewing muscles stronger, but there's no good evidence they change how your jawline looks. In a 2024 report of two people who used one for about three months, neither noticed a change in jaw appearance, and the authors point out that these workouts don't affect bone structure or facial shape.
What they can do
Build bite strength and endurance. In a trial of 49 healthy young adults who trained with silicone chewing tubes, bite force and endurance went up, peaking after about 3 months of training (2013 study).
Fade fast. In that same study, the gains dropped off once people stopped training.
Make the masseter bigger. That is the point of the tool, but a bigger masseter doesn't automatically mean a sharper jaw. Clinical reviews describe an enlarged masseter as giving the lower face a wider, squarer look, which is why some people seek treatment to shrink it (2025 clinical review). We found no study on how much a bite tool contributes to that. The same applies to hard chewing gum: it loads the same muscle, and a 2024 trial found no change in jaw shape after six months.
What they can't do
Change bone. The authors of the 2024 case report state that jaw workouts don't change the underlying bone structure or facial shape.
Reduce a double chin. In that report, neither person saw a change in double chin.
Burn fat from your face. The authors of the 2024 case report say the chewing muscles have no direct effect on fat under the chin. A meta-analysis of 13 controlled studies (1,158 people) also found that training one body area doesn't reduce fat in that area (meta-analysis). That research is on limbs, not jaws, but it points the same way.
The case report is tiny, so it's a weak signal, not proof. But we also didn't find a controlled study testing whether a jaw exerciser changes how a jawline looks.
Jawline Exerciser Before and After: How to Read the Photos
Most jawline exerciser before-and-after photos don't prove the tool worked, because lighting, camera angle, head position, weight and facial tension can change how a jaw looks within minutes. A photo pair counts as evidence only if everything except the tool stayed the same.
Check these before you trust a photo pair
Camera distance and angle. Closer lenses and lower angles change jaw width and chin size.
Head position. A raised chin or a slight tilt shows more jaw and neck line.
Light. Light from above or the side carves shadows under the jaw; flat front light erases them.
Expression. Clenched teeth make the masseter pop, relaxed jaws look softer.
Weight and timing. Weeks or months apart is enough for body weight and water retention to change the face.
Who posted it. A brand's own page has a reason to pick the best pair.
We break down the same photo tricks in our guide to mewing before and after photos, and the checklist works for any jaw transformation.
How to take honest photos of your own
Use the same spot, same light and same camera distance every time.
Keep your head level and your jaw relaxed, with the same expression.
Shoot front and side, at the same time of day.
Compare at the same body weight.
Why your jaw might look wider after using one
The muscle you're training sits at the back corner of the jaw. If it grows, the lower face can look fuller or squarer from the front, not sharper (see the masseter point above). If your jaw looks wider, or feels sore, stop and don't push through it.
Are Jawline Exercisers Safe?
Not necessarily. A jaw exerciser adds load to muscles and a joint that already work all day, and dental researchers have warned that repeated hard biting could strain the temporomandibular joint (TMJ), the hinge that connects your jaw to your skull. We didn't find long-term safety studies on using these tools for looks.
What dentists have warned about
Joint strain. The UK dental researchers behind the 2021 letter wrote that repeated use could put far more stress on the TMJ and wear the joint's disc, with possible symptoms from clicking to dislocation (British Dental Journal).
Comparison to grinding. The same authors compared the load to what people who grind their teeth put on the jaw.
It's a common area to have problems. An estimated 5% to 10% of people in the U.S. have some form of temporomandibular disorder (TMD), so plenty of people using these tools may already have a sensitive jaw (NIDCR).
Ask a dentist first if you have
Jaw pain, clicking or locking
A history of TMD, clenching or teeth grinding
Braces, recent dental work or loose teeth
If you're under 18 or have braces, check with a dentist or orthodontist before using any bite tool.
Stop and see a dentist if
Your jaw hurts during or after use
Your jaw clicks, catches or locks
Your bite feels different
Persistent jaw pain or locking is a reason to see a dentist or doctor, not to try a lighter setting.
How Long and How Often Should You Use a Jawline Exerciser?
There's no evidence-based schedule for jaw exercisers. Brands publish their own routines, and no study shows that any of them sharpens a jawline. The only timeline we found is for muscle strength: in a 2013 training trial, bite force and endurance peaked after about 3 months of regular training and faded once training stopped (study).
So "how long until it works" has two different answers:
Stronger bite: months of regular use, and it doesn't last without it
Visibly sharper jawline: no study shows this happens
If you try one anyway
Start with the lightest resistance you can get
Stop at any jaw pain, clicking or headache
Take rest days, since your jaw already works every time you eat and talk
Skip it entirely if you have a jaw problem (see the safety section above)
Best Jawline Exerciser? What to Look For
No jawline exerciser has been shown to sharpen a jawline, so there’s no “best” one for looks. The same goes for jawline gum and mastic gum. If you still want to try one, choose by safety and fit: adjustable, low starting resistance, food-grade silicone, a shape that sits comfortably, and marketing that doesn't overpromise.
What to check before you buy
Resistance: a light level you can build from, not a fixed heavy one
Material: food-grade, BPA-free silicone with no strong chemical smell
Fit: it should sit comfortably between your teeth without forcing your jaw to strain
Price: current shopping results range from a few dollars to well over $50, and a higher price isn't evidence of better results
Red flags in the marketing
Guaranteed or "transformation" results
Claims that it works dozens of facial muscles at once
"Clinical study" pages written by the brand itself
Claims that it relieves jaw pain or TMJ problems (the dental researchers behind the 2021 letter objected to exactly this kind of claim)
Before-and-after photos with no information on lighting, timing or who the person is
Jawline exerciser for men and women
"For men" and "for women" packs are the same kind of tool sold to different audiences. We found no study comparing results by sex, so choose by fit and comfort, not by the label on the box.
What Actually Changes How a Jawline Looks
A jawline looks sharp because of three things: bone structure (how defined your jaw angle and chin are), the amount of fat under the chin and along the jaw, and skin and muscle tone. A jaw exerciser only touches muscle, which is why it rarely changes the picture.
Bone structure: set by genetics and growth, and not something a bite tool changes
Body fat: lower overall body fat usually makes the jaw easier to see
Skin and posture: how the skin sits over the jaw and neck, and how you hold your head
Grooming: haircut, facial hair and framing change how a jawline reads in photos
For the full list of what helps and what doesn't, see our breakdown of how to sharpen your jawline. If you're curious how a jawline is scored and what goes into it, our jawline rating guide explains it, and looksmaxxing covers where jawline work fits in the bigger picture.
FAQ
Are jaw exercisers legit?
They're real devices that do train your chewing muscles. What isn't backed up is the promise of a sharper jawline or a smaller double chin: a 2024 case report of two users found no noticeable change in jaw appearance, and we found no controlled study showing otherwise.
How long does it take for a jaw exerciser to work?
For bite strength, months: in a 2013 trial it peaked after about 3 months and faded after training stopped. For a visibly sharper jawline, there's no study showing it happens at all.
Is it safe to use a jawline exerciser?
It can strain the jaw joint, especially with heavy resistance or an existing jaw problem. UK dental researchers warned about this in 2021. If you have jaw pain, clicking or locking, ask a dentist before using one.
Do jaw exercisers make your face wider?
They can make the masseter bigger, and an enlarged masseter is described in clinical reviews as giving the lower face a wider, squarer look. We found no study measuring how much a bite tool contributes.
Do jaw exercisers reduce a double chin?
Probably not. Neither person in the 2024 case report saw a change in double chin, and the tool trains chewing muscles, not the fat under the chin.
Sources
Verma KK et al. Facial Contouring Through Jaw Exercises: A Report of Two Cases Examining Efficacy and Consumer Expectations. Cureus, 2024.
Nagpal T, Gupta A. Jaw dropping. British Dental Journal, 2021.
He T et al. Effects of masticatory muscle training on maximum bite force and muscular endurance. Acta Odontologica Scandinavica, 2013.
Ramírez-Campillo R et al. A proposed model to test the hypothesis of exercise-induced localized fat reduction (spot reduction), including a systematic review with meta-analysis. Human Movement, 2022.
The Role of Botulinum Toxin for Masseter Muscle Hypertrophy: A Comprehensive Review. Toxins, 2025.
National Institute of Dental and Craniofacial Research. Temporomandibular Disorders.
