Injectables
Masseter Botox (Jaw Slimming)
Reliably narrows a genuinely wide lower face over 4–8 weeks. Note the direction: this makes the jaw smaller, which is the opposite of what most people here want.
Also called: jaw botox · masseter reduction · face slimming injection
Verdict — legit
Does what it claims, with evidence behind it.
Evidence grade B
At least one good randomised trial, or consistent findings across controlled studies.
Mechanism
Chemodenervation atrophies the masseter through disuse, reducing lateral bulk at the mandibular angle. The bone is untouched.
Citations
- Botulinum toxin type A for the treatment of masseter hypertrophy: an ultrasonographic studyDermatologic Surgery · 2005
- Efficacy and safety of botulinum toxin in masseter reduction: a systematic reviewAesthetic Plastic Surgery · 2020
The full read
Well supported by trials and by the bruxism literature, with measurable reductions in masseter thickness on ultrasound. It is the correct answer to a specific complaint — a square, wide lower third from muscle hypertrophy, often alongside clenching and tooth wear — and the wrong answer to a soft or undefined jawline, which is a fat, skin or skeletal problem. Effects last four to six months and repeat treatment produces cumulative atrophy. Over-treated, it can hollow the lower cheek and, rarely, affect the smile if the risorius is caught. Read it alongside `jaw-clenching`: the two entries describe the same muscle, moved in opposite directions, by two groups who each believe they are improving their jaw.