Masseter Botox for Teeth Grinding: Does It Actually Work?

Masseter botulinum toxin injections — commonly called masseter Botox or jaw Botox — are used to reduce overactivity in the masseter muscles. This has two practical effects: it can reduce teeth grinding (bruxism) and jaw clenching, and it can slim the lower face over time. Here is what the evidence says, what treatment involves, and what to expect.

What Is the Masseter Muscle?

The masseter is one of the primary chewing muscles, running from the cheekbone down to the jawbone on each side of the face. In people who clench or grind their teeth — particularly at night — this muscle can become hypertrophic (enlarged) from overuse. An enlarged masseter makes the lower face look wider and squarer, and contributes to jaw pain, headaches, and tooth wear.

How Do Anti-Wrinkle Injections Help with Teeth Grinding?

Botulinum toxin temporarily reduces muscle contraction strength in the masseter. With the muscle partially relaxed, the force of clenching decreases. This does not eliminate grinding entirely — especially unconscious nocturnal bruxism — but many people notice a meaningful reduction in jaw tension, morning headaches, and tooth soreness.

The treatment addresses the muscular component of bruxism. It does not treat underlying causes such as stress, sleep disorders, or dental misalignment. For this reason, it is often used alongside other approaches (a dental night guard, stress management) rather than as a standalone solution.

What Does the Evidence Say?

Several clinical studies have examined botulinum toxin for bruxism. Results consistently show reductions in muscle activity and self-reported jaw pain, though study sizes tend to be modest. A 2019 systematic review published in the Journal of Oral Rehabilitation found that botulinum toxin injections significantly reduced masseteric muscle activity and pain symptoms in bruxism patients.

It is worth noting that botulinum toxin is not a Health Canada–approved indication specifically for bruxism; it is used off-label for this purpose. The evidence is supportive but the research base is smaller than for cosmetic facial applications. Clients should discuss this context with their practitioner.

V-Shape Slimming: The Cosmetic Benefit

When the masseter is hypertrophic, the lower face can appear wide or boxy. Repeated rounds of masseter injections reduce the muscle’s bulk over time, gradually creating a slimmer, more tapered jawline — often described as a V-shape effect.

This cosmetic result takes longer than a standard anti-wrinkle treatment. The initial relaxation effect appears within 1–2 weeks, but visible jaw slimming typically develops over 4–6 weeks as the muscle volume reduces. Results are most pronounced after 2–3 treatment cycles.

What the Treatment Involves

The practitioner palpates the masseter to identify its borders, then injects several points on each side. The procedure takes approximately 15 minutes and requires no downtime. You may experience mild tenderness or swelling at the injection sites for a day or two.

Chewing function is preserved — you will not have difficulty eating. Extremely tough foods (very hard crunchy items) may feel slightly different for a few weeks as the muscle adjusts, but normal eating is unaffected for most people.

How Long Do Results Last?

The functional effect on jaw clenching typically lasts 3–6 months. The cosmetic slimming effect can persist longer — sometimes 6–9 months — because the reduction in muscle bulk is a gradual structural change rather than just a functional one. With consistent treatment, some clients find they need top-ups less frequently over time.

Who Is a Good Candidate?

• People with confirmed or suspected bruxism causing jaw pain, headaches, or tooth wear
• Those with a wide or square lower face due to hypertrophic masseters
• Clients who have tried a night guard but want additional symptom relief

It is not appropriate for everyone. A consultation is the correct place to assess muscle anatomy, discuss goals, and determine whether treatment is suitable.

Masseter Treatment at MJ Aesthetics

At MJ Aesthetics in North York, anti-wrinkle injections for the jaw — including TMJ tension relief, masseter slimming, and bruxism management — are offered as part of the injectable treatment menu. Masseter and V-shape treatments are priced per unit at the standard rate of $6.50/unit.

Book a free consultation to discuss whether masseter treatment is appropriate for your situation.

Frequently Asked Questions

Will masseter Botox change how I chew?

Chewing ability is not significantly affected. The masseter is not fully paralysed — its contraction is reduced, not eliminated. Most people notice no change in normal eating.

How quickly will I notice results for teeth grinding?

Many clients notice reduced jaw tension within 1–2 weeks. Morning headaches and tooth soreness often improve in the first few weeks after the muscle relaxes.

Do I still need a night guard?

Anti-wrinkle injections reduce clenching force but do not eliminate tooth contact during grinding. A dental night guard protects the teeth directly, so many clients use both approaches together. Consult your dentist about whether a guard is appropriate for you.