Why is botulinum toxin type A used in jaw slimming injections?

The masseter is a strong chewing muscle at the angle of the jaw. Repeated clenching or naturally prominent muscle bulk can contribute to a broader, more square-looking lower face. Botulinum toxin type A reduces the nerve signal that makes the injected masseter contract. As the muscle works less, it may gradually become less prominent. The treatment cannot narrow jawbone structure or remove fat, so it is not suitable for every facial shape.

Possible short-term effects include injection-site tenderness, bruising, chewing fatigue or a change in bite comfort. Precise anatomy assessment helps reduce the chance of unwanted spread to nearby muscles.

Tell your clinician about jaw pain, clenching, dental treatment, swallowing problems, facial weakness, medicines and previous injections. The clinician may assess your bite and ask you to clench so the masseter can be located. Follow aftercare instructions and contact the clinic if chewing becomes difficult or facial movement changes. Dental or joint causes of jaw discomfort may need separate care rather than cosmetic injections.

Ask for prompt medical advice if swelling, warmth, discharge or worsening pain develops around an injection site. Seek urgent help for difficulty swallowing, speaking or breathing, rapidly developing weakness, or facial swelling with hives. Report persistent difficulty chewing, a marked bite change or uneven smile to the treating clinician for assessment.

Ask whether your lower-face width is mainly muscle-related, how chewing function will be protected, what change is realistic, and which alternatives might suit your anatomy.