Masseter Botox Dosage: How Many Units Are Needed for Jawline Slimming?

Masseter Botox is one of the most effective non-surgical treatments for jawline slimming, teeth grinding, and facial contouring. One of the most common questions patients have is: “How many units of Botox will I need?”

At Dr Hass Clinic, we tailor every Masseter Botox treatment to your individual anatomy, muscle strength, and aesthetic goals. Understanding dosage helps patients set realistic expectations, optimise results, and maintain safety.

The masseter is the main chewing muscle, located at the back of your jaw. Botox works by temporarily relaxing this muscle, which leads to:

• Reduced jaw clenching and teeth grinding (bruxism)
• Gradual slimming of the jawline over several weeks
• Improved facial symmetry and proportion

The amount of Botox needed depends on muscle size, strength, and desired effect, which is why there is no single standard dose.

For jawline slimming in adults, the average dosage per side typically falls between 20–40 units, although some patients may require slightly more or less. Key points to note:

• Mild slimming / small masseters: 20–25 units per side
• Moderate slimming / average masseters: 25–35 units per side
• Significant muscle hypertrophy / very strong masseters: 35–40+ units per side

Note: These are approximate ranges. Only a qualified injector can determine the precise dosage based on a personalised assessment.

The dosage used for Masseter Botox can be influenced by:

1. Muscle Size and Thickness
Thicker, stronger masseters need more units to achieve noticeable slimming. Muscle size is assessed by palpation and visual observation of the jawline at rest and during clenching.

2. Desired Degree of Slimming
Some patients want subtle contouring, while others want a more dramatic narrowing. Conservative dosing reduces the risk of over-relaxation and uneven results.

3. Previous Treatments
Patients who have had prior Botox may require fewer units because the muscle is already partially relaxed. Repeat treatments are adjusted based on previous response.

4. Facial Symmetry
Slight differences between the left and right masseter muscles may require asymmetric dosing to achieve balance. Symmetry is critical for a natural-looking jawline.

5. Gender and Age
Men often require slightly higher doses due to stronger jaw muscles. Age may influence muscle strength and skin elasticity, affecting how the dosage is calculated.

Proper injection technique is essential for effective results and minimal side effects:

• Multiple injection points: Typically 2–4 per side to evenly distribute the toxin
• Depth of injection: Into the bulk of the masseter muscle, avoiding superficial placement
• Unit allocation: Units are divided across the injection points for consistent relaxation
• Safety considerations: Avoids diffusion into nearby muscles (e.g., risorius or platysma), which could affect chewing or smile

After treatment, patients may notice:

• Mild tenderness or swelling at injection points
• Softening of the jaw muscle in 1–2 weeks
• Gradual slimming of the lower face over 4–8 weeks
• Maximum effect typically at 6–8 weeks, lasting 4–6 months

Tip: It is important to avoid massaging or applying pressure to the area immediately after treatment to prevent uneven distribution.

Masseter Botox is highly safe when performed by a qualified practitioner:

• Only use medical-grade Botulinum toxin
• Dosage is calculated according to muscle strength and aesthetic goals
• Over-relaxation can lead to temporary weakness when chewing; conservative dosing prevents this
• Follow-up checks at Dr Hass Clinic ensure results are symmetric and natural-looking

At Dr Hass Clinic, every Masseter Botox treatment is:

• Doctor-led: Administered by Dr Hasaneen Al Janabi, GMC-registered and Royal College of Surgeons member
• Personalised: Dosage is customised for your jawline, muscle size, and desired contour
• Followed up: Routine checks ensure optimal results and allow adjustments if necessary
• Safe: Minimal downtime, predictable results, and natural aesthetics

Your treatment is not “one-size-fits-all.” Personalised dosing and precise injection technique are what make Masseter Botox both effective and safe.

• Typical dosage per side: 20–40 units depending on muscle size and goals
• Factors influencing dosage: muscle strength, symmetry, gender, age, prior treatments
• Multiple injection points are used for even muscle relaxation
• Results develop gradually over 4–8 weeks and last 4–6 months
• Personalised dosing and follow-ups are essential for safety and natural results