Does chewing gum help your jawline? A six-month trial says no
58 adults chewed gum daily for six months. Bite force rose; masseter thickness and jaw shape did not. What that means for mastic gum and jaw trainers.
Table of contents
- Key numbers
- Does chewing gum change your jawline
- Does harder gum work better
- Wait — do you even want a bigger masseter
- So what actually makes a jawline show
- What about jaw trainers, and is any of it risky
- The bottom line
- Studies referenced
You are on day nine of chewing until your jaw aches. The mastic gum sits beside your keyboard, the tub cost more than dinner, and a paused before-and-after promises a new face. Look closer: the “after” has better lighting, a lower camera angle, and a lighter-looking body.
So, does chewing gum help your jawline? For ordinary gum, the best direct trial says no. Bite force increased after six months, but masseter thickness and mandibular shape did not. Harder resistance may build muscle; that is not the same as carving a visible edge into your face.
The useful question is whether you are loading the layer hiding the result you want. Usually, you are not.
TL;DR
- Ordinary gum: A six-month randomised trial found stronger biting, not a changed jawline.
- Hard resistance: A resistance device increased masseter thickness in elderly participants, so the muscle question is real.
- The catch: A bigger masseter can widen the lower face, which is why reduction treatments exist.
- Visible definition: Facial and submental fat usually matter more to whether an edge shows.
- Best decision: Do not spend a year chewing through jaw pain while assuming effort guarantees facial change.
Key numbers
- 58 adults: Jung et al. (2024) randomised adults to gum three times daily for six months.
- 6 weeks: Kim et al. (2020) found thicker masseters after high-resistance chewing in elderly participants.
- r = 0.71: de Jager et al. (2018) found raters estimated body mass from facial cues alone, n = 458.
- 66.5% vs 22.2%: Humphrey et al. (2016) reported this one-grade improvement for submental-fat treatment versus placebo.
- 8 studies: Alam et al. (2025) reviewed gum chewing and temporomandibular disorders.
Does chewing gum change your jawline?
No, not in the trial that tested ordinary gum most directly. Jung et al. (2024) followed 58 adults chewing three times daily for six months. Maximum occlusal force increased, but masseter thickness and mandibular shape did not change significantly.
The force gain came from increased occlusal contact area: the teeth met over a more useful area. That is dental performance, not a more angular cheek or remodelled bone. Read the published randomised trial on PubMed: the desired outcome was facial shape; the measured change was force.
“Jawline before and after” videos are weak proof because camera height, head position, expression, hydration, facial hair, lighting and body composition change the read. A close-up can look more dramatic while anatomy stays the same.
Does harder gum work better?
Possibly for the masseter. Kim et al. (2020) used isometric and isotonic exercises with a high-resistance device for 20 minutes a day, 5 days a week for six weeks in 40 elderly participants. Occlusal force and masseter thickness both improved significantly. Ordinary gum in healthy adults over six months did not.
Resistance is therefore a real variable: muscle can respond differently to demanding load than casual chewing. But a thicker masseter is not a reshaped adult mandible, and the participants and device differed from a young man buying mastic gum after a short video.
The honest limit is that one ordinary-gum trial cannot answer every possible resistance, dose or starting anatomy; it can answer the ordinary promise much better than marketing can.
For the narrower evidence question, read whether jawline exercises work. The answer stays narrow: resistance may affect muscle; no verified result here shows chewing changes bone or reliably reveals a clean jaw edge.
Photo: cottonbro studio on Pexels
Wait — do you even want a bigger masseter?
Usually, no. Masseter hypertrophy is commonly described as a cosmetic concern because it can widen the lower face. People seek botulinum toxin masseter reduction to look slimmer, and a 2026 meta-analysis supports that treatment direction.
A larger masseter is not bad on every man; some prefer more width. But “more chewing” is not universal improvement. If your complaint is a soft or hidden jawline, adding width at the middle layer may miss it.
| Layer of the jawline | Can chewing change it? | What actually changes it |
|---|---|---|
| Mandible (bone) | No demonstrated adult shape change | Growth, orthodontic or surgical factors, depending on the problem |
| Masseter (muscle) | Resistance may increase thickness | Training load, or reduction treatment when prominence is unwanted |
| Submental and subcutaneous fat | Not a reliable route | Overall fat loss or targeted clinical treatment |
| Skin laxity | No | Time, tissue quality and appropriate clinical options |
The literature is blunt: Sonar and Panchbhai say the common reason patients with masseteric hypertrophy seek treatment is facial appearance; Kundu et al. describe it as a cosmetic concern because it may widen the lower face. A face can look broader without looking more defined.
Worth steelmanning the other side: some men genuinely do want a wider lower face, and for them a bigger masseter is not a failure mode. The point is only that "wider" and "sharper" are opposite requests, and the gum is sold as though they were the same one.
So what actually makes a jawline show?
Mostly the layer over the structure: facial and submental fat. A trial of ATX-101 reported at least a one-grade improvement in 66.5% versus 22.2% with placebo, confirmed by MRI. It does not recommend injections for everyone; it shows that changing the covering layer can change visible contour.
The perception evidence points the same way. de Jager, Coetzee and Coetzee found raters estimated body mass index from facial cues alone at r = 0.71, n = 458; lower perceived facial adiposity was rated more attractive and healthier. The face is not read as bare bone.
That is the reframe: chewing trains the wrong layer. A jawline is bone, masseter, then fat and skin. Chewing loads only the middle layer — and ordinary gum did not move it in the direct six-month trial. If the top layer hides the edge, a year training the middle layer is effort pointed sideways.
For a practical route, start with body fat percentage for a visible jawline, then read how to lose face fat without expecting spot reduction. The face-fat and jawline myth, gonial angle, and body fat and first impression pages separate changeable factors from photo staging.
We are arguing against a cheap habit from behind a free test we would like you to use, so weigh this accordingly — and note that our test cannot tell you whether anything will change your jaw either.
What about jaw trainers, and is any of it risky?
No peer-reviewed trial has evaluated Jawzrsize, Jawliner or any branded jaw-exercise device, so “studies show they do not work” is also too strong. There is no branded-device efficacy result, but repeated high loads plausibly stress the jaw.
Nagpal and Gupta warned that repeated use would likely stress the temporomandibular joint and wear the articular disc. A 2025 systematic review of eight studies found the gum-chewing/TMD association complex: some studies found a dose-response relationship, others only transient symptoms. Jaw pain, clicking or headaches are reasons to stop and seek dental advice, not increase the dose.
Mewing belongs in the same category of internet certainty. No systematic review exists. The British Orthodontic Society statement says no scientific evidence shows that holding the teeth and tongue in that position changes facial shape; the American Association of Orthodontists explanation says no current research suggests a jawline or oral-health benefit. See does mewing work and weak jawline in men.
Chewing is cheap, visible and feels like progress, which is why it spreads. The real cost is not the twelve dollars of gum; it is a year spent on the wrong layer.
The bottom line
Does chewing gum help your jawline? Ordinary gum did not change masseter thickness or mandibular shape in the six-month randomised trial. Hard resistance may build masseter, adding width rather than definition; no peer-reviewed trial has shown chewing reshapes an adult jaw.
Identify what obscures the edge: surface fat, skin laxity, camera distortion, or structure you cannot train away. A jawline is the visible result of several layers, and strangers read the whole arrangement quickly.
That is why we keep coming back to chewing trains the wrong layer. For a fast estimate of how your photos may read to a stranger, try our free perception test, not a clinical instrument. It is a perception estimate on a 70–155 axis, not a diagnosis, facial scan or promise that chewing changes anatomy. Compare a second set of photos with the same perception test, not a clinical instrument after targeting the relevant layer.
Studies referenced
- Alam, M. K., Shayeb, M. A., Natarajan, P. M., et al. (2025). Association of temporomandibular disorders and other jaw anomalies in chewing gum users — a systematic review. Journal of Oral & Facial Pain and Headache, 39(2), 35–47. doi:10.22514/jofph.2025.022
- American Association of Orthodontists (2025). Does mewing actually reshape your jaw? https://aaoinfo.org/whats-trending/is-mewing-bad-for-you/
- British Orthodontic Society (2025). Statement on facial exercises and "mewing". https://bos.org.uk/statements/the-british-orthodontic-society-would-like-to-reiterate-the-following-statement/
- de Jager, S., Coetzee, N., & Coetzee, V. (2018). Facial adiposity, attractiveness, and health: a review. Frontiers in Psychology, 9, 2562. doi:10.3389/fpsyg.2018.02562
- Humphrey, S., Sykes, J., Kantor, J., et al. (2016). ATX-101 for reduction of submental fat: a phase III randomized controlled trial (REFINE-2). Journal of the American Academy of Dermatology, 75(4), 788–797.e7. doi:10.1016/j.jaad.2016.04.028
- Jung, H. J., Hwangbo, N. K., Park, Y., & Ahn, H. J. (2024). Effects of gum chewing training on occlusal force, masseter muscle thickness and mandibular shape: a randomised controlled clinical trial. Journal of Oral Rehabilitation, 51(12), 2529–2536. doi:10.1111/joor.13830
- Kim, H. J., et al. (2020). Effects of chewing exercises on the occlusal force and masseter muscle thickness in community-dwelling elders. Journal of Oral Rehabilitation, 47(9). doi:10.1111/joor.13036
- Kundu, N., Kothari, R., Shah, N., et al. (2022). Efficacy of botulinum toxin in masseter muscle hypertrophy for lower face contouring. Journal of Cosmetic Dermatology, 21(5), 1849–1856. doi:10.1111/jocd.14858
- Machado, G. F., et al. (2026). Botulinum toxin for masseter muscle hypertrophy: a systematic review and meta-analysis. Journal of Plastic, Reconstructive & Aesthetic Surgery, 119, 212–225. doi:10.1016/j.bjps.2026.06.012
- Nagpal, T., & Gupta, A. (2021). Jaw dropping. British Dental Journal, 230(4), 185. doi:10.1038/s41415-021-2750-4
- Sonar, P. R., & Panchbhai, A. S. (2024). Case report: Masseter hypertrophy: a case and review. F1000Research, 12, 1263. doi:10.12688/f1000research.140341.2
Frequently asked questions
Does chewing gum actually change your jawline?
Not in the one randomised controlled trial that tested it properly. Fifty-eight adults chewed gum three times a day for six months; maximum bite force rose, but masseter muscle thickness and mandibular shape did not change significantly (Jung et al., 2024). The bite-force gain came from increased tooth contact area, which is a dental effect, not a facial one.
What about mastic gum or jaw trainers — is hard gum different?
Possibly for the muscle, and still not for the bone. A separate six-week study using a high-resistance chewing device did increase masseter thickness significantly. So resistance seems to matter. But no study has shown chewing of any kind changing the shape of an adult mandible, and no peer-reviewed trial has evaluated the branded jaw-exercise devices at all. A dental journal letter warned that repeated use of such a device likely puts more stress on the jaw joint and wears the articular disc (Nagpal & Gupta, 2021).
If chewing builds the masseter, isn't that good?
Clinically, an enlarged masseter is treated as a cosmetic problem, not a goal. The medical literature describes masseter muscle hypertrophy as presenting with cosmetic concerns because it widens the lower face, and injecting botulinum toxin to shrink the muscle is an established lower-face slimming procedure with meta-analytic support. Thousands of people pay every year to make their masseters smaller.
Then what does make a jawline visible?
Mostly the fat layer over it. Facial adiposity drives how faces are read — raters could estimate body mass from facial cues alone at r = 0.71 — and people with lower perceived facial adiposity are rated more attractive and healthier (de Jager et al., 2018). A trial that removed submental fat with injections produced improvement in 66.5 percent of patients versus 22.2 percent on placebo. The body-fat route is covered in body fat percentage for a visible jawline.
Is chewing gum all day risky?
It carries some risk and the evidence is mixed rather than alarming. A 2025 systematic review of eight studies found the association between gum chewing and temporomandibular disorders to be complex, with some studies showing a dose-response relationship and others finding only transient symptoms. Jaw pain, clicking or headaches after chewing sessions are a reason to stop, not to push through.