Square Jaw (Masseter) Treatment in Cheongdam & Apgujeong, Seoul

Muscle, bone or fat?

The masseter is the strong chewing muscle that runs from the cheekbone to the angle of the jaw. When it is large, it pushes the lower face outward at the angles and creates the squared shape known in Korean as 사각턱. But a wide jaw can come from three different sources, and the right treatment depends on which one dominates.

• Muscle. Masseter enlargement is the most common cause. It is influenced by genetics, habitual clenching, night-time teeth grinding and a preference for hard or chewy foods. A useful sign: the bulge becomes firm and more prominent when you clench.
• Bone. Some people have a naturally wide or flared jaw angle. Muscle treatments soften the overlying contour only slightly in this case.
• Fat. Subcutaneous fat over the lower cheek and angle can add width, especially when combined with early sagging.

Most square jaws are a mix, with muscle playing the largest part. Age also changes the picture: in a younger face, slimming the muscle usually gives a clean V-shaped taper, whereas in a face with laxity, removing bulk can let the skin above sag a little more visibly.

How Doje Clinic assesses a square jaw

In a 1:1 consultation, Dr. Byun Jeik palpates the masseter at rest and during clenching, compares both sides (asymmetry is common), and looks at the jaw from the front and in three-quarter view. He also checks the cheek and jowl above the muscle, because the condition of the tissue that sits on top of the masseter decides whether slimming alone is enough.

• How thick and active is each masseter?
• Is there clenching or grinding that will keep stimulating the muscle?
• How much of the width is bone or fat rather than muscle?
• Is there early laxity that should be supported when the muscle shrinks?

Options from mild to advanced

Muscle-dominant square jaw

Botulinum toxin injected into the masseter — jaw Botox — relaxes the muscle, and with less use it gradually becomes smaller. Slimming typically becomes visible over several weeks rather than days. Because the muscle can regain bulk as the effect wears off, repeat treatments are often planned, with intervals adjusted to how your muscle responds. Dosing and injection points are individualised to avoid an over-hollowed look or an uneven smile.

Square jaw with early laxity

When the skin and soft tissue over the jaw have started to loosen, slimming the muscle removes some of the support beneath them. Doje may combine toxin with the Doje signature lower-face thread lift or energy lifting such as Ultherapy Prime so the contour stays smooth. The comparison jaw Botox vs jawline thread lift explains how the two differ.

Width from fat

If fat over the angle contributes, ONDA, listed as an option in the Jawline Program, may help reduce it over a course of treatment.

Clenching and grinding

Toxin can reduce the force of clenching as a side benefit, but teeth grinding is a dental issue too. A dentist can assess whether a night guard or bite treatment is advisable alongside aesthetic care.

Which Doje program fits

For a straightforward muscle-driven square jaw, jaw Botox as a single treatment is often enough. When width comes with sagging, fat under the chin or a blurred jawline, the Jawline Program — lower-face thread lift and double-chin liposuction, with Radiesse, Ultherapy Prime and ONDA as options — provides a fuller plan built on structural sagging, fat and skin elasticity.

When a surgical opinion is more appropriate

If the width comes mainly from the shape of the jaw bone, toxin will soften the contour only modestly. Bone contouring surgery is the option that changes skeletal width, and it requires assessment by a qualified surgeon. Dr. Byun will tell you if your jaw is bone-dominant so you can make an informed decision.

Cost

Fees depend on whether you need toxin alone or a combined plan, and are quoted after the 1:1 consultation. Ask for a written quote; Korean non-covered (비급여) aesthetic fees are set per plan.

Frequently asked questions

How do I know if my square jaw is muscle or bone?

Clench your teeth and feel the angle of your jaw: a firm bulge that grows on clenching suggests muscle. A physician's examination confirms how much is muscle, bone or fat.

How soon will my jaw look slimmer?

Slimming is gradual and typically becomes visible over several weeks as the muscle reduces in size.

How long does masseter Botox last?

It varies with dose, muscle strength and habits such as clenching. Repeat sessions are usually needed to maintain the effect.

Can jaw Botox cause sagging?

In a face with existing laxity, reduced muscle bulk can make sagging slightly more visible. Doje assesses this first and may combine toxin with lifting.

Will it affect chewing?

Some people notice mild chewing fatigue with hard foods for the first few weeks; this is usually temporary.

Can it help teeth grinding?

It may reduce clenching force, but grinding should also be assessed by a dentist, who can advise on protecting the teeth.

Related at Doje Clinic

• Jaw (Masseter) Botox
• Jawline Program
• Jaw Botox vs Jawline Thread Lift
• Heavy Lower Face
• Undefined Jawline
• Botox
• Botox Aftercare

Medical information on this page is general education, not a diagnosis. Suitability, risks and the final plan are confirmed in a 1:1 consultation with Dr. Byun Jeik. Last updated 17 October 2026.