Masseter Botox for TMJ and Jawline Slimming: What to Know

Masseter neurotoxin injections are one of the few aesthetic treatments that address both appearance and function. If you're dealing with jaw tension, teeth grinding, or TMJ discomfort — or you simply want a slimmer jawline — here's what you should know about the treatment. View our Masseter Reduction treatment page →

What Is the Masseter Muscle?

The masseter is one of the primary muscles used for chewing, located on each side of the jaw. When this muscle is overactive — from clenching, grinding, or simply genetics — it can become enlarged, creating a wider or more square jawline. It can also contribute to jaw pain, headaches, and TMJ discomfort.

How Masseter Botox Works

A small amount of neurotoxin — Botox, Dysport, or Xeomin — is injected into the masseter muscle on each side. The neurotoxin temporarily relaxes the muscle, which does two things:

• Reduces jaw tension and grinding — the muscle can no longer clench with the same force, relieving TMJ symptoms
• Slims the jawline over time — as the muscle relaxes, it gradually decreases in size, creating a more contoured facial profile

The treatment takes about 10-15 minutes. Most patients notice tension relief within a few days and visible slimming within 2-4 weeks.

Masseter Botox for TMJ Relief

TMJ disorder affects the jaw joints and surrounding muscles, causing pain, headaches, and difficulty with everyday activities like eating and speaking. Common symptoms include:

• Jaw pain or soreness, especially in the morning
• Frequent headaches or migraines
• Teeth grinding (bruxism), often during sleep
• Clicking or popping when opening the jaw
• Jaw locking or limited range of motion

By relaxing the masseter muscle, neurotoxin injections reduce the clenching force that causes many of these symptoms. Many patients report significant relief after their first treatment.

Masseter Botox for Jawline Slimming

Beyond TMJ relief, masseter reduction is one of the most popular non-surgical options for facial contouring. Patients with a naturally square or wide jawline — often due to enlarged masseter muscles — can achieve a slimmer, more tapered facial profile without surgery.

The slimming effect is gradual. As the muscle relaxes and decreases in size over 2-6 weeks, the lower face appears more contoured. Results typically last 3-6 months, with many patients finding that regular treatments lead to longer-lasting results as the muscle stays in a more relaxed state.

What to Expect: Before, During, and After

Before

• Avoid blood thinners, NSAIDs, and alcohol for 48 hours before treatment
• Your provider will evaluate your jaw muscles and discuss your goals during a consultation

During

• Neurotoxin is injected into the masseter muscle on each side using a fine needle
• The treatment takes 10-15 minutes
• Most patients describe mild discomfort — no anesthesia needed

After

• Return to normal activities immediately
• Avoid strenuous exercise and rubbing the treated area for 24 hours
• Tension relief within days, visible slimming within 2-4 weeks
• Follow-up treatments recommended every 3-6 months

Is Masseter Botox Right for You?

This treatment may be a good fit if you:

• Experience jaw tension, clenching, or teeth grinding
• Have TMJ-related headaches or jaw pain
• Want a slimmer jawline without surgery
• Have a naturally square jaw from enlarged masseter muscles

A consultation with your provider is the best way to determine if masseter neurotoxin treatment is appropriate for your concerns.

Learn more about our Masseter Reduction treatment and pricing →

Medically reviewed by Dr. Steven Chao, California Medical Director at NakedMD