By LIV Clinic · Medically reviewed by Dr. Narathai Vichienkalayarut, M.D. · Published July 28, 2026

A softer jawline without an operating theatre — possible, but only if muscle is what is making it wide.

Can Botox slim a wide jaw without surgery? Yes — if the width comes from an enlarged masseter muscle, Botox can gradually slim it over several weeks with no surgery or downtime. If the width comes from bone structure, however, Botox will not change it and surgery would be the only option.

The key question: muscle or bone?

Muscle-driven width

If your jaw looks wide because the masseter muscle is enlarged — common in clenchers and grinders — Botox can help by relaxing it so it gradually slims.

Bone-driven width

If the width comes from the shape of the jawbone itself, Botox will not change it. Only surgical jaw reduction alters bone, which is a major procedure.

How to tell

Clench your teeth and feel the jaw — if a firm muscle bulges noticeably, muscle is likely a factor. A consultation confirms this properly.

How Botox slims the masseter

Relaxing, then reducing

The Cleveland Clinic describes Botox blocking the signal that makes a muscle contract. With less contraction, the masseter gradually reduces in bulk.

Gradual and natural

Because the change comes from muscle reduction over weeks, the slimming looks natural rather than sudden.

Botox vs surgical jaw reduction

Which suits you depends on whether muscle or bone is driving the width.

What results look like

The timeline

Clenching force reduces within one to two weeks, while visible slimming develops over roughly four to eight weeks as the muscle reduces.

Longevity

Results typically last around four to six months. With repeated treatments, the muscle can stay slimmer for longer between sessions.

Who it suits

Masseter Botox for slimming tends to suit:

• Those with a strong, bulging masseter when clenching
• People who clench or grind their teeth
• Anyone wanting a softer, more V-shaped lower face
• Those who prefer to avoid surgery
• People comfortable with a temporary, repeatable result

Limits and safety

Honest expectations

Botox cannot narrow bone, will not lift sagging skin, and the result is temporary. If your goal needs bone change, a surgeon is the right conversation.

Injector experience

The masseter is large and deep, so correct dose and depth are essential to slim safely without affecting your smile or chewing. The American Academy of Ophthalmology notes Botox should be avoided in pregnancy or breastfeeding and with certain neuromuscular conditions.

Preparing for and recovering from jaw Botox

Preparation and aftercare are simple:

1. Have a consultation so Dr. Narathai can assess whether muscle or bone drives your jaw width.
2. Avoid alcohol and blood-thinning supplements for 24–48 hours before, where appropriate.
3. Arrive with clean skin.
4. Stay upright and avoid rubbing the jaw for the first few hours.
5. Avoid saunas, heat, sun and heavy exercise for the first day.
6. Allow 4–8 weeks for slimming to show, then review.

Non-surgical jaw slimming on Koh Samui

At LIV Clinic, jaw slimming with masseter Botox is doctor-led by Dr. Narathai, who will tell you honestly whether it can achieve your goal. Explore our Botox and wrinkle treatments, read about Botox for jaw clenching and grinding, or book a consultation.

Frequently asked questions

Safety and consultation

Masseter Botox is a medical procedure and, like any injectable, carries some risk — common temporary effects can include redness, swelling, bruising or a mild headache, and less common reactions are possible. Results vary from person to person, and no specific outcome can be promised. This article is general information, not medical advice.

At LIV Clinic, every treatment begins with an in-person assessment by Dr. Narathai Vichienkalayarut, M.D., who reviews your skin, medical history and goals before recommending a personalized plan. Book a consultation to find out whether this treatment suits you.