Does chewing gum help your jawline? What the research says about mastic gum

Does chewing gum give you a jawline?

Chewing gum works your masseter, the thick muscle at the back corner of your jaw. Like any muscle, it can get stronger with use. That is the whole idea behind jawline gum.

But a defined jawline mostly comes from your bone shape and how little fat sits over it. Gum changes neither. At most, it might add some muscle at the jaw angle. That makes the lower face wider and squarer, not sharper. And the best trial found no measurable change in muscle size at all.

Source: Jung and colleagues, 2024: Effects of gum chewing training on occlusal force, masseter thickness and mandibular shape, randomized trial (J Oral Rehabil)

What is the masseter muscle, and can it get bigger?

The masseter runs from your cheekbone down to the angle of your jaw. Clench your teeth and put your fingers just in front of your earlobe and below. The bulge you feel is the masseter.

Some people have large masseters, a condition called masseter hypertrophy. It widens the lower face and makes it look square. Doctors treat it, when people want a narrower face, with botulinum toxin injections that relax and shrink the muscle. A 2026 review of five trials found those injections reduced muscle thickness.

So a bigger masseter is real, and it does change face shape. Whether gum chewing can build one in a healthy adult is a separate question.

Source: Botulinum toxin for masseter muscle hypertrophy, systematic review and meta-analysis, 2026 (J Plast Reconstr Aesthet Surg)

What does the research say about gum and the jaw?

Two studies tested chewing training directly. Neither looked at how attractive a jaw looks. They measured strength and muscle size.

Source: Kiliaridis and colleagues, 1995: Effects of fatigue and chewing training on maximal bite force and endurance (Am J Orthod Dentofacial Orthop)

Why gum will not fix a soft jawline

If your jaw looks soft because of fat under the chin and along the jaw, chewing will not remove it. Training a muscle does not take fat from over that muscle. Spot-reduction trials on the belly and legs show the same thing.

Muscle size also matters less than people think. Even if gum did add muscle, that muscle sits under the same layer of fat and skin. At a higher body fat, extra muscle shows as a wider, fuller lower face, not a sharper edge.

If your jaw looks soft because of your bone, gum will not move bone in an adult. If it is posture, you need to change how you hold your head. Gum only touches one factor, the muscle, and the evidence on that is weak.

Source: Vispute and colleagues, 2011: The effect of abdominal exercise on abdominal fat (J Strength Cond Res)

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What is mastic gum?

Mastic is a natural resin from the mastic tree, Pistacia lentiscus. The European Medicines Agency has a herbal monograph for it. It lists traditional uses for minor digestive complaints, skin problems and minor wounds. Most mastic sold as Chios mastic comes from the Greek island of Chios.

As a chewing gum, it starts as hard, brittle pieces that soften as you chew. It is firmer and harder work than normal gum, which is why jawline sellers promote it. There are no published trials of mastic gum for jawline or masseter growth.

Source: European Medicines Agency: mastic (Pistacia lentiscus L., resin) herbal monograph

Does mastic gum help your jawline more than regular gum?

It is harder to chew, so it works your jaw harder per minute. That may raise bite strength faster, similar to the hard gum in the 1995 study. It does nothing extra for fat or bone.

Expect sore jaw muscles at first. No study has measured whether mastic changes the size of the jaw muscles. If your jaw starts to click with pain, ache in the morning or lock, stop.

Mastic is a plant product, and research on it mostly covers digestion and heart health markers. If you have a tree nut or plant resin allergy, check with a pharmacist first.

Source: Chios mastic gum: a promising phytotherapeutic for cardiometabolic health, review, 2024 (Nutrients)

Regular gum vs mastic gum vs jawline exercisers

Here is how the three common options compare on what the evidence shows.

Can chewing gum cause TMJ problems?

TMD, often called TMJ, is a group of problems with the jaw joint and chewing muscles. The US National Institute of Dental and Craniofacial Research estimates about 5% of US adults have it. Signs include jaw pain, pain spreading to the face or neck, stiffness, locking, and painful clicking or grating.

The NIDCR's self-care advice for TMD includes reducing habits like jaw clenching and gum chewing. A 2025 systematic review of 8 studies found mixed results. Some found no lasting link, while others found that more chewing went with more jaw symptoms such as muscle pain.

If you already have jaw pain or clicking with pain, skip jawline gum and devices. If pain lasts or your bite changes, see a dentist.

Source: National Institute of Dental and Craniofacial Research: TMD (temporomandibular disorders)

If you still want to try jawline gum

It is your call. If you try it, keep the load low and stop at the first sign of jaw trouble.

1. Take a front and side photo at eye level in daylight before you start.
2. Start with 10 to 15 minutes a day of regular sugarless gum, not a hard device.
3. Switch sides every few minutes so one side does not take all the work.
4. Do not chew until it hurts, and take days off.
5. Stop if your jaw clicks with pain, aches in the morning, gets stiff or locks.
6. Retake the same photos after 8 to 12 weeks and compare them side by side.

Source: NHS: temporomandibular disorder (TMD)

What helps your jawline more than gum

The things that change how a jaw looks are less exciting and more reliable. Lower your body fat slowly. Hold your head level. Shape your beard along the jaw. Get a haircut that balances your face. Shoot photos at eye level or a little higher.

Skip mewing as a jaw fix and never try bonesmashing. Orthodontists say mewing has no evidence for reshaping the jaw, and hitting your face risks real injury.

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Check whether anything changed with Lookist

The honest test for any jaw routine is a before and after with the same setup. Lookist gives a jawline score with a written note, plus chin, cheekbones and facial harmony, from one front photo.

Scan history lets you compare scans over time. Take your first scan before you start and repeat it with the same light and camera height. If nothing changed in the photos, the gum did not do much for your look, whatever the bite force did.

Try the face rating tool

Track facial changes over time