Botox for masseter reduction, or Dysport for masseter reduction, is an excellent procedure to reduce the tension in the jaw, decrease grinding of the teeth, relieve stress in the lower face, and to slim the appearance of the jawline and face. As a neuromodulator, the mechanism of action of Botox and Dysport is to work at the neuromuscular junction to prevent the presynaptic release of acetylcholine, thereby relaxing the muscle by preventing its contraction. As new synapses form within the neuromuscular junction, this effect subsides until eventually full function of the target muscle returns – typically in 3-4 months.
During the time the neuromodulator (Botox or Dysport) is active in the muscle, the muscle becomes relaxed and can not contract with its normal force. The masseter muscle is one of four muscles involved in chewing, and when it becomes relaxed will reduce the intensity of bruxism or teeth grinding and clenching, relieve stress associated with tension in the lower face and bite, and will slim the face by reducing in size and volume.
Does Botox or Dysport permanently reduce the masseter muscle? No, it can not make a permanent change as it will only relax the masseter muscle in a temporary fashion, typically relaxing the muscle for 3-4 months. Once the masseter muscle function returns, the bulk and volume of the muscle will return, typically a total of 4-6 months after the treatment.
How many units of Botox does it take to reduce a masseter?
For most patients undergoing Botox for masseter reduction, 20-30 units per side is a typical range, with 25 units per side being the most common initial dosing.
With Dysport for masseter reduction, a 3:1 conversion for equivalency, which means 60-90 units of Dysport per side, or 75 units per side.
How long does it take for your masseter to shrink after Botox or Dysport?
The muscle will relax and clenching, grinding and stress symptoms will decrease in ~1 week. Once relaxed, the masseter muscle will take 4-6 weeks to visibly shrink in size, and it will continue shrinking and slimming your face for the 3-4 months that Botox or Dysport is active.
