Injecting botulinum toxin into the masseter muscle reduces clenching and grinding, relieves jaw and temple tension, and gradually slims a square lower face. It is one of the few aesthetic treatments with a genuine functional benefit.
What it is
- The masseter is the thick chewing muscle at the angle of the jaw. Chronic clenching (bruxism) makes it hypertrophic, which widens the lower face and causes pain, headaches and tooth wear.
- Toxin partially weakens the muscle so it relaxes and, over months, reduces in bulk.
Who it suits
- Teeth grinding, morning jaw stiffness, temple headaches
- A wide, square lower face caused by muscle rather than bone or fat
- Patients with tooth wear or dentist-diagnosed bruxism
- Not suitable in significant chewing weakness or certain temporomandibular joint disorders without dental assessment
Products we use
Original licensed botulinum toxin, typically 20–30 units per side depending on muscle bulk
How the treatment is performed
- Palpation of the muscle while you clench, to map bulk and safe injection zones.
- Two to three deep injection points per side.
- No anaesthesia usually required.
Safety
- Injection must stay within the muscle body and away from the risorius to avoid an asymmetric smile.
- Dose is matched to muscle bulk; excessive dosing can cause chewing fatigue or a hollow cheek.
Before your appointment
No specific preparation; mention any TMJ diagnosis or dental treatment plans.
Aftercare
Avoid massaging the area for 24 hours; chewing normally is fine.
Results and longevity
- Clenching relief within 1–2 weeks.
- Visible slimming from week 4–6, maximal at 3 months.
- Repeat treatments give progressively longer intervals.
Possible side effects and risks
- Temporary chewing fatigue when eating hard foods.
- Uncommon: asymmetric smile if product spreads, hollowing with excessive long-term dosing.
- Bruising at injection points.
Follow-up
Review at 4 weeks; dose adjusted at the next session based on response.
Questions about this treatment
Will my face look thinner immediately?
No. Pain relief comes first; visible slimming takes four to eight weeks as the muscle reduces.
Can I still chew normally?
Yes. Some patients notice fatigue with very hard food in the first weeks, which resolves.
Does it help headaches?
Often yes, when headaches originate from clenching and temporal muscle tension.