Jawline Slimming Treatment in Marylebone, London
Masseter anti-wrinkle treatment reduces a wide or square jawline and resolves clenching and bruxism at the same time.
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A wide lower face is often the result of masseter hypertrophy — the masseter is the powerful chewing muscle that sits over the angle of the jaw, and in patients who habitually clench or grind (often during sleep without realising) it can enlarge significantly, creating a square or wide lower-face appearance. The same muscle is also the primary culprit in bruxism-related jaw pain, tension headaches, and dental wear.
Anti-wrinkle treatment of the masseter (40 to 50 units of Botox or equivalent per side) both slims the lower face over 8 to 12 weeks as the muscle atrophies from disuse, and resolves the clenching pain and bruxism symptoms within 2 to 3 weeks. This is one of the few aesthetic treatments with a dual clinical benefit, and for some patients the functional relief (sleeping better, waking without jaw pain, no more dental splint) is more valuable than the aesthetic slimming.
What drives this concern
- Chronic bruxism (teeth grinding) enlarges the masseter muscle
- Daytime clenching from stress, focus, or concentration
- Genetic predisposition — some jaws are naturally wider
- Heavy chewing of tough foods (gum, nuts, dried meats) can contribute
- Underlying bone structure — orthognathic-level wideness is not treatable with botulinum toxin alone
Treatment options for jawline slimming
Anti-Wrinkle Injections
From £250Primary treatment. 40 to 50 units of botulinum toxin per side into the belly of the masseter muscle. Functional relief of bruxism within 2 to 3 weeks; aesthetic slimming visible over 8 to 12 weeks; maintain every 6 months.
See treatment detail →Dermal Fillers
From £350For patients whose chin projection is out of proportion with the now-slimmed jawline, a small volume of chin filler rebalances the profile after masseter treatment takes effect.
See treatment detail →FAQ
Common
questions
How long does masseter treatment take to work?
Functional relief of jaw tension, clenching, and bruxism symptoms begins within 3 to 7 days and is fully established by 2 to 3 weeks. Aesthetic slimming of the lower face develops more gradually as the muscle atrophies from reduced activity — you typically see measurable slimming at 6 to 8 weeks, with the full effect at 12 weeks. Photos taken at baseline and 12 weeks make the change very clear.
Will I struggle to chew after masseter treatment?
No. The medial pterygoid and temporalis muscles (the other two chewing muscles) are completely unaffected, and the masseter is only partially weakened — not paralysed. Most patients notice no change in eating ability. Some patients report mild fatigue of the muscle when chewing unusually tough food (gum, steak) during the first 2 weeks, which resolves as compensation adapts.
How often do I need masseter treatment?
Every 6 months for the first 2 years is typical, after which the muscle stays meaningfully slimmed even if you skip a cycle — the atrophy from reduced activity compounds over time. Maintenance often stretches to every 8 to 12 months in long-term patients. Bruxism symptoms return if treatment is stopped completely after significant untreated grinding.
How much does masseter treatment cost?
£450 for bilateral masseter treatment (both sides), including the 2-week review. This is the most common "dual-purpose" treatment at this clinic — patients book it as much for the aesthetic slimming as for the bruxism relief. If you have been paying for dental splints and Advil, the functional maths often justifies the treatment alone.
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Dr Valentina Aesthetics • 1 Orchard Street, London W1H 6HJ
Book a SessionAppointments typically available within 1–2 weeks