Jawline and masseter assessment at Dr Sin Yong's clinic, Orchard Road, Singapore
Masseter Assessment · Orchard Road, Singapore

Jaw Botox & Face Slimming

A wide lower face has four possible causes — masseter hypertrophy, buccal fat, skin laxity, or the jaw bone itself. Only one of them responds to botulinum toxin, and telling them apart takes about a minute.

Doctor-ledEvery assessment by Dr Sin Yong
MBBS · MRCS · MSc ×2NUS · Edinburgh · London · Cardiff
Orchard RoadBy appointment

Four Causes, One Treatment

Patients ask for jaw botox having decided the answer before the question. Sometimes they are right. Often they are not.

Masseter hypertrophy is muscle. The masseter sits at the angle of the jaw and, like any muscle, enlarges with use. Habitual clenching, nocturnal bruxism and a preference for firm foods all build it. This is the presentation that responds to masseter botox.

Buccal fat sits in the cheek, higher and more forward. It is fat, not muscle, and treating the muscle does nothing for it.

Skin laxity blurs the jawline rather than widening the face. Here the outline has softened; nothing has grown.

Mandibular width is skeletal. A wide bony angle produces a wide lower face, and no injectable changes bone. Saying so plainly is more useful than treating and hoping.

The Test That Settles It

Clench your teeth firmly and place your fingers at the angle of the jaw, just in front of and below the ear.

If a firm bulge appears under your fingers, the masseter is enlarged and part of the picture. If nothing much changes, the width is coming from somewhere else — and botox jaw reduction would be treating the wrong structure.

It takes a minute, it is done at every consultation, and it is the difference between a plan and a guess.

How It Works, and What It Does Not Do

Botulinum toxin blocks acetylcholine release at the neuromuscular junction. The masseter contracts less; with reduced use it undergoes disuse atrophy over the weeks that follow. The change is muscular, and it is gradual.

Dr Sin Yong's primary formulation is Dysport®, a prescription-only medicine requiring assessment. Its potency units are specific to its own assay and are not interchangeable with other botulinum toxin products — a unit figure quoted from another clinic using a different product is not comparable.

Where the cause is fat or laxity rather than muscle, other approaches apply — submental assessment for the area below the jaw, or focused ultrasound where the jawline has lost definition rather than gained width.

Response varies with muscle bulk, the degree of hypertrophy, and individual anatomy. Botulinum toxin is a prescription medicine; suitability, risks and side effects are discussed at consultation, and it is not appropriate for every patient.

Key Facts

At a glance
The four causes
Masseter hypertrophy; buccal fat; skin laxity; the width of the mandibular angle
What responds to botulinum toxin
Masseter hypertrophy only. The other three do not
Mechanism
Botulinum toxin blocks acetylcholine release at the neuromuscular junction; reduced contraction leads to disuse atrophy of the muscle over the following weeks
Primary formulation
Dysport® (abobotulinumtoxinA), a prescription-only medicine
Units are not interchangeable
Dysport potency units are specific to its own assay and cannot be converted to those of other botulinum toxin products
The bedside test
Clench the jaw. If the angle visibly bulges and firms, the masseter is involved. If it does not, something else is
Common driver
Nocturnal bruxism and habitual clenching. The muscle enlarges with use, like any muscle
Not changed by injection
Mandibular bone width. That is skeletal, and no injectable alters it

“Clench your jaw. If it bulges, the muscle is part of the picture. If it doesn't, no amount of botulinum toxin will change your face shape.”

Dr Sin YongOn assessing a wide jaw

What Determines the Cost

Treatment is planned individually, so cost follows the plan rather than a fixed list. Four things shape it:

Factors discussed at consultation

  • The area treated. A single zone differs from several, and surface area drives the work involved.
  • What the assessment finds. The same appearance can have different causes, and the cause decides the approach.
  • Whether one modality or several. Some presentations are addressed by a single approach; others are not.
  • How the plan is staged. Work spread over time is planned differently from work done in one visit.

A figure quoted before assessment would not reflect your presentation. Cost is set out clearly at consultation, before anything is agreed.

Jaw Botox & Face Slimming — Frequently Asked Questions

Jaw botox refers to injecting botulinum toxin into the masseter muscle at the angle of the jaw. The toxin blocks acetylcholine release at the neuromuscular junction, so the muscle contracts less and undergoes disuse atrophy over the following weeks. It addresses muscle bulk only, not fat, skin laxity or bone.

Clench your teeth firmly and feel the angle of the jaw, just in front of and below the ear. If a firm bulge appears, the masseter is enlarged and involved. If little changes, the width is coming from buccal fat, skin laxity or the width of the jaw bone itself. This is checked at consultation before any plan is made.

No. It addresses masseter hypertrophy. Where the lower face is wide because of buccal fat, skin laxity or the shape of the mandible, botulinum toxin treats the wrong structure and the appearance does not change. Establishing which applies is the purpose of assessment.

The masseter enlarges with use, like any muscle. Habitual clenching, nocturnal bruxism and a preference for firm or chewy foods are common drivers. Many patients are unaware they clench at night, and a dental history is part of the assessment.

Dr Sin Yong's primary formulation is Dysport (abobotulinumtoxinA), a prescription-only medicine. Its potency units are specific to its own preparation and assay method and are not interchangeable with other botulinum toxin products, so unit figures quoted between clinics using different products are not comparable.

No. Mandibular width is skeletal, and no injectable changes bone. Where the bony angle is the cause, that is discussed honestly at consultation rather than treated in the hope of a result.

Cost depends on the degree of hypertrophy identified at assessment, whether one side or both require treatment, and how the plan is staged. Because these differ between patients, a figure quoted before assessment would not be meaningful. Cost is set out clearly at consultation.

Suitability is assessed in person. Neuromuscular conditions, pregnancy and breastfeeding, certain medications, and known sensitivity to any component are among the things considered. Botulinum toxin is a prescription medicine and requires medical assessment before use.

Explore Further

Related Pages

Speak With Dr Sin Yong

Consultations by appointment at Orchard Road, Singapore.

WhatsApp +65 8023 7170 →