Masseter Slimming

Masseter slimming is aimed at the muscular type of wide lower face: when you clench your teeth, a firm, visibly bulging muscle can be felt at the outer angle of the jaw, and the lower face still looks broad at rest. Masseter enlargement is often linked to chewing tough foods over time, nighttime teeth grinding, jaw clenching, or habitually chewing on one side. The goal is a narrower, softer contour around the jaw angle—not an overall smaller face.

The treatment only reduces muscle bulk, so it cannot fix the other two common causes of a wide lower face. A bony wide face comes from the shape of the mandible itself; injections cannot change bone, and improvement is usually limited. A fat-dominant round face is driven by cheek fat and calls for a different kind of assessment. Contouring surgery and facial liposuction are separate procedures and beyond the scope of this entry.

Botulinum toxin type A blocks the release of acetylcholine at nerve endings, temporarily weakening the masseter's contraction. With less activity, the muscle gradually shrinks through disuse, and the lower face narrows as a result. During consultation the physician typically asks you to clench, palpates the muscle to judge its thickness and position, weighs how much of the facial width is actually muscular, and reviews your medical history and current medications.