Concerns · Lift & Contour · CityLink Mall
Wide Jaw & Square Face Treatment in Singapore
A square lower face is often a strong chewing muscle rather than bone. Telling the two apart is the whole point of the first visit.
Written & medically reviewed by Dr Sin Yong · 8 October 2026
Quick answer
- A square lower face is often a strong chewing muscle rather than bone. Telling the two apart is the whole point of the first visit.
- Medical, performed by Dr Sin Yong at IN Eternity Clinic (Pacific Plaza, Orchard): Jaw Slimming Injections.
- Assessment first; individual results vary. Medical pricing is given at consultation.
A wide or square jaw makes the lower face look broader than the cheekbones, so the face reads as square rather than tapered. Many people first notice it in front-facing photos or when hair is tied back. If you are looking for a wide jaw treatment in Singapore, the first thing to know is that the width can come from the masseter muscle, from the angle of the jawbone, from fat or salivary glands, or from a mix. Only some of these respond to injections.
The masseter is the thick chewing muscle at the back corner of the jaw. Clench your teeth and you can feel it harden under your fingers. Like any muscle, it grows with use. Night-time grinding, daytime clenching, chewing gum, and hard or chewy food habits can all enlarge it over years. Genes and ethnicity also matter, and a prominent masseter is common in East Asian faces. When the muscle is the main cause, the width often looks fuller when you bite down.
Bone works differently. A flared jaw angle stays the same whether you clench or relax, and only surgery changes bone shape. Fat at the jowl or a prominent parotid gland can also widen the lower face. Because the main treatment for a large masseter is a prescription injection, SkinRev Lab does not perform it. Enquiries can start with us, and the assessment and injections are performed by Dr Sin Yong at IN Eternity Clinic.
“If your jaw is wide because of bone, an injection will not narrow it, and a good doctor will say so before treating.”
— Dr Sin Yong, IN Eternity Clinic
- Types
- Muscle-dominant (masseter hypertrophy), bone-dominant (flared jaw angle), soft tissue or gland related, or mixed
- Simple self-check
- Muscle width hardens and bulges when you clench; bone width does not change
- How the injection works
- A neuromodulator reduces nerve signals to the masseter, so the muscle is used less and gradually thins
- Bite-force effect
- Maximal bite force measured lower for at least 3 months after a single treatment in one study
- Change develops over
- Several weeks, as the muscle slowly reduces in bulk
- Related habits
- Night grinding (bruxism), daytime clenching, frequent gum chewing
What goes where
The honest ladder:
non-invasive first, medical when it is needed
At SkinRev Lab · non-invasive
There is no non-invasive treatment at SkinRev Lab that changes this concern. We will say so at the first visit and pass your enquiry to IN Eternity Clinic.
At IN Eternity Clinic · Dr Sin Yong
Jaw Slimming Injections — Dr Sin Yong examines the jaw at rest and when clenched, maps the bulk of the masseter, and places small doses of a wrinkle-relaxing injection (neuromodulator) into the muscle at measured points. The muscle softens and thins over the following weeks. Performed at IN Eternity Clinic, with a review to check symmetry and chewing comfort. Small bumps or tenderness at the injection points usually settle within a day, and most people return to work straight after. How it works
Enquiries to SkinRev Lab about medical treatments are passed to IN Eternity Clinic, where Dr Sin Yong performs them.
There is no non-invasive device at SkinRev Lab that reliably slims an enlarged chewing muscle, so we do not suggest one. You can still message us first, and we route your enquiry to the clinic. See the doctor first in every case where you want the jaw narrowed, and especially if you grind your teeth, have jaw pain or clicking, notice one side larger than the other, or have recently noticed a new lump near the angle of the jaw. Dr Sin Yong at IN Eternity Clinic will check whether muscle, bone, gland or fat is the main cause and whether a dental or other medical opinion is needed first. If you grind at night, a dentist-made guard may still be needed to protect your teeth, whatever is done for the jaw shape.
Where this happens
Assessment and non-invasive care — SkinRev Lab, CityLink Mall #B1-28, 1 Raffles Link, Singapore 039393. Underground from City Hall MRT and Esplanade MRT; a short walk from Raffles Place, Marina Bay, Suntec and Bugis. Open daily 11am–8pm.
Medical treatment — IN Eternity Clinic, 9 Scotts Road, #12-01 Pacific Plaza, Singapore 228210, beside Orchard MRT (three stops from City Hall on the North-South line). Mon–Sat 11am–8pm, closed Sunday. Treatments are performed by Dr Sin Yong. WhatsApp +65 8815 3008.
What the research says
The evidence,
with sources
A 2026 systematic review and meta-analysis pooled five randomised, placebo-controlled studies with 536 people. Neuromodulator treatment of the masseter improved muscle prominence scores, reduced muscle thickness and raised satisfaction compared with placebo, mainly in the short term. The authors noted large differences between studies and said the evidence is not yet enough to set an ideal dose or protocol. An earlier systematic review of 28 studies found wide variation in how many injection points were used and recommended using as few as possible until stronger evidence appears.
Function matters as much as looks. In a one-year study, a single treatment of both masseters measurably reduced maximum bite force at three months, and the effect was no longer significant by six months. The authors noted that the visible slimming may last longer than the change in strength. This is why doses are kept measured, and why people who chew hard foods or have dental concerns should mention them at consultation.
References
- Machado GF, De Freitas LR, Ribeiro LFS, et al. Efficacy of botulinum toxin for masseter muscle hypertrophy: a systematic review and meta-analysis. J Plast Reconstr Aesthet Surg. 2026;119:212-225.
- Rauso R, Lo Giudice G, Tartaro G, et al. Botulinum toxin type A injections for masticatory muscles hypertrophy: a systematic review. J Craniomaxillofac Surg. 2022;50(1):7-18.
- Ågren M, Nanchaipruek Y, Phumariyapong P, et al. Duration of bite force reduction following a single injection of botulinum toxin in the masseter muscle bilaterally: a one-year non-randomized trial. J Oral Rehabil. 2023;50(5):343-350.
Common questions
Your questions,
answered
What is the usual wide jaw treatment in Singapore if the cause is muscle?
When the masseter muscle is the main cause, the most common approach is a wrinkle-relaxing injection (neuromodulator) placed into the muscle by a doctor. It reduces how hard the muscle works, so it thins over several weeks and the lower face looks narrower. At SkinRev Lab we do not perform injections; this is done by Dr Sin Yong at IN Eternity Clinic after an examination.
How much does wide jaw treatment in Singapore cost?
Jaw slimming injections are a medical treatment, so pricing is given at consultation with Dr Sin Yong at IN Eternity Clinic. The amount needed depends on muscle size, how strong your bite is and whether both sides are equal, so a fixed figure without examining you would not be honest. You will know the cost before treatment begins.
Will my chewing feel weaker?
Some people notice that tough or chewy food tires the jaw for a few weeks. In one study, maximum bite force dropped measurably at three months and recovered by six months. Most people adapt without difficulty, but tell the doctor if you chew hard foods often, play wind instruments or have dental or jaw joint problems, since the dose and placement may need adjusting.
How long does the slimming last?
The effect usually fades gradually over several months as nerve signals to the muscle recover. Research suggests the visible slimming can outlast the change in bite strength. How long it lasts varies with your muscle size, habits such as grinding, and dose. Many people choose to repeat treatment when they notice the width returning, and the interval is agreed with the doctor.
Can it make my face look saggy?
In some people, especially those with thin skin or early jowling, reducing the bulk at the jaw angle can make soft tissue in front look heavier. Uneven smiles and a temporary bulge in part of the muscle are other possible effects. These risks are why careful dosing and placement matter, and why Dr Sin Yong checks skin quality and jowls before treating.
What if my wide jaw is bone, not muscle?
If the width stays the same when you clench and relax, bone is the likely cause, and injections will not change it. Bone reshaping is surgery done by maxillofacial or plastic surgeons. Dr Sin Yong can explain this at consultation. For some people, adding definition at the chin makes the lower face look more tapered without touching the jaw angle.