If you wake up with a tight jaw, get headaches from clenching, or feel your jaw has grown wide and square, the cause is usually the same muscle doing too much work. Masseter Botox relaxes it — which eases the symptoms and softens the jawline at the same time.
From £280
masseter · jaw grinding & slimming
2–3 weeks
for the muscle to relax
3–6 months
results typically last
New client · free · no obligation
The masseter is the large chewing muscle at the back of the jaw. For a lot of people it is constantly overworked — clenching through the day, grinding at night, or both without realising it. Over time that leads to jaw tension, headaches, worn teeth, and a jawline that looks visibly squared or overdeveloped because the muscle itself has grown.
Masseter Botox is prescription-only botulinum toxin injected into that muscle to relax it. Nothing is added and nothing is removed — the muscle simply stops working overtime, and the jaw returns towards its natural shape. It is the same medicine as anti-wrinkle treatment, used for a different job: this one treats a problem rather than a line.
Your treatment is carried out by an Independent Nurse Prescriber — Georgie and her team of nurse prescribers. Because we prescribe as well as treat, the dose is set by how your muscle actually behaves rather than by a fixed template.
It treats the muscle. If the shape of your jaw comes from fat or bone structure instead, masseter Botox is not the right answer and we will tell you so at consultation rather than treat you anyway.
A few small injections into each side of the jaw. It is quick, there is no downtime, and you can return to your day straight away. Your dose is decided by the size and strength of your muscle, assessed at consultation — which is why masseter treatment is priced on assessment rather than as a fixed one-size dose.
The muscle relaxes gradually rather than overnight. Most people notice the tension easing first, with the visible softening of the jawline building over about two to three weeks. You will come back for a free review so we can see how your muscle has responded and adjust the next dose if it needs it.
Masseter Botox suits people who clench or grind — particularly if it causes pain, headaches or worn teeth — and people who want to soften a jaw that has become square from muscle overuse. It is not suitable during pregnancy or breastfeeding, or if you have certain neuromuscular conditions, and the consultation covers all of that honestly.
One thing worth saying plainly: this is not a weight-loss treatment and it will not slim a face where the shape comes from fat. If that is your concern, we will point you at what actually helps instead — even if that is nothing we offer.
Botulinum toxin is not a fashion — it is one of the most studied medicines in aesthetic and dental practice. A 2019 systematic review of randomised clinical trials in Medicina Oral, Patología Oral y Cirugía Bucal found that injections into the masseter (and/or temple) muscles reduced the frequency of grinding episodes, pain levels and maximum bite force, concluding it is a safe and effective treatment — especially in people with severe grinding. A 2024 meta-analysis of eleven studies found grinding-related pain fell by an average of 4.06 points on a 10-point pain scale straight after treatment, and that it outperformed both bite splints and saline injections.
What the research is honest about: a 2025 overview of fourteen systematic reviews in Toxins found the evidence pointed consistently in the same direction, but rated the methodological quality of those reviews as critically low, and none assessed the certainty of the evidence properly. In plain terms — the direction is clear and it matches what we see clinically, but this is not a field with the same grade of evidence as, say, blood-pressure medication. If your case is mild, a bite guard from your dentist may be a sensible first step, and we will say so.
Mild tenderness or a slight ache in the muscle for a day or two is normal and settles. Come back for your free review so we can judge whether the dose was right for you.
This is the treatment people mean when they search for jaw slimming, and it does work for the right cause. A wide, square jaw from an overbuilt muscle softens as the muscle relaxes. A wide jaw from fat, or a strong bone structure, does not — and no amount of Botox changes bone. At consultation we feel the muscle and tell you which one you have. That is the whole point of the free appointment.
Masseter and hyperhidrosis sit on the same functional side of our Botox menu — treatments that solve a problem. Hyperhidrosis treatment uses Botox to block the nerve signals that drive the sweat glands, dramatically reducing underarm sweating for around six months. It starts from £380. There is more detail in our guide to functional Botox in Basingstoke, or see excessive sweating.
Masseter Botox starts from £280. The dose is set by the size and strength of your muscle, so the exact price for you is confirmed at your free consultation — you get an itemised price before anything is booked. Most people have two to three treatments a year to keep the effect going. The full injectables menu is on our prices page.
From £280, with the exact price set by the dose your muscle needs. You get an itemised price at your free consultation, before anything is booked.
It's a quick injection treatment with no downtime — you can go straight back to your day. We talk you through exactly what we're doing as we do it.
Usually around three to six months, depending on the dose and how you respond. Most people have two to three treatments a year.
It can soften an overdeveloped, squared jawline as the muscle relaxes — which is often exactly why people have it. It won't affect bone or fat, and the change is gradual and natural over a few weeks.
Yes. For any new client a consultation must happen before treatment — it is a legal requirement for the administration of Botox. Yours is free, with no obligation.
Masseter Botox relaxes muscle to narrow a jaw that has become square. Filler adds volume — for example to a chin or to balance a profile. They do opposite things and suit different faces; we'll tell you which one yours needs. See jawline and contours for the full picture.
Read Masseter Botox & hyperhidrosis in Basingstoke for the honest long version, or the Botox cost guide for how our pricing works.
Masseter Botox is part of our anti-wrinkle and injectables menu, alongside frown and forehead lines and excessive sweating. For a different take on the same medicine see Botox for men, or Baby Botox if you want a lighter dose. If the jawline is your main concern, start from jawline and contours, or see how we approach the wider injectables aftercare.
That's the whole question with a jaw. A consultation is the honest way to find out — we'll feel the muscle and tell you what's realistically achievable.
Book a free consultation