Masseter Botox in London: Jaw Slimming and Teeth Grinding

Q: How much does masseter Botox cost in London?

Cost is confirmed at consultation.

The masseter is the strongest muscle in the body for its size, and in some faces it is doing far more than chewing. Relaxing it with a prescription muscle-relaxing injection slims a square jaw over six weeks and quiets grinding within two. The risks are a lopsided smile and a weak chew, and both come down to where the needle goes. I taught anatomy before I did this, and it shows in the mapping.

Masseter Botox is the injection of botulinum toxin, a prescription-only muscle-relaxing medicine, into the masseter, the thick chewing muscle at the angle of the jaw, to reduce its bulk and its overactivity. It is used for two things: to slim a square or wide lower face where the width comes from muscle rather than bone, and to relieve teeth grinding, clenching, jaw tension and the morning headaches that come with them. The treatment takes 30 minutes, needs no anaesthetic and has no downtime. Grinding eases within ten to fourteen days; visible slimming begins at four weeks and peaks at six to eight; the effect lasts four to six months and lengthens with repeat treatment as the muscle shrinks. Because the medicine is prescription-only, it is prescribed after a face-to-face consultation with me. Your fee is confirmed at consultation, once your treatment plan is agreed.

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GMC

Registered Doctor

MRCS

Royal College of Surgeons

10 to 14 days
Grinding relief

ABOUT THE MASSETER

Why your jaw looks square or feels heavy, and what the injection does

The masseter runs from the cheekbone to the angle of the jaw, and every time you chew, clench or grind, it contracts. Like any muscle it grows with use. In people who clench at their desk or grind at night, who chew gum for hours, or who simply inherited a strong jaw, it thickens until the angle of the jaw squares off and the lower face looks as wide as the cheekbones. That is masseter hypertrophy, and it is the commonest reason a face looks wider than it used to; the second commonest is fat, and the third is bone, and the consultation is where I tell you which you have. A muscle-driven jaw responds to this treatment; a bony one does not; a fatty one needs a different plan.

The medicine blocks the signal from the nerve to the muscle, so the masseter contracts less. Two things follow. Within ten to fourteen days the grinding and clenching lose their force, the jaw ache and tension headaches settle, and dentists see less wear on the teeth. Then, over four to eight weeks, a muscle that is no longer working hard shrinks, and the angle of the jaw softens from a square to a curve, usually by a few millimetres each side, which is enough to change the shape of a face. The effect wears off over four to six months as the nerve endings recover, but a muscle that has been quiet for months regrows slowly, and by the third or fourth treatment most patients need it less often.

What it does not do: it does not change bone, so a genuinely square mandible needs a surgeon; it does not remove fat, which is fat dissolving or HIFU territory; and in loose skin, slimming the muscle can unmask jowls, which I check for before treating anyone over forty-five and manage with skin boosters or Sofwave alongside. My blog on why your face looks wider explains the stress-jaw pattern in detail.

WHO IT IS FOR

Three reasons patients come for masseter Botox

Most people have a bit of each. The dose and the mapping change depending on which matters most to you.

Jaw slimming

A square, wide or heavy lower face where the width is muscle. The angle of the jaw softens to a V or oval over six to eight weeks. The most requested reason.

Teeth grinding and clenching

Bruxism, jaw tension, morning headaches, tooth wear and a clicking jaw. Relief within two weeks; a night guard protects the teeth but does not stop the clenching.

Facial balance and asymmetry

One masseter bigger than the other from chewing on one side, or a jaw that competes with the cheekbones. Dosed side by side to even the face.

Nefertiti neck lift

For a jawline blurred by the platysma pulling down rather than by masseter bulk. Often combined.

Chin and jawline filler

Where the jaw is narrow rather than wide, or the chin is short. The opposite problem, and sometimes done together to balance a face.

Fat dissolving for the jowl and chin

Where the lower-face width is fat rather than muscle. Assessed by pinching, not guessing.

THE TREATMENT

What happens at the consultation and the treatment

The consultation takes 15 to 20 minutes. I ask about grinding, clenching, headaches, dental wear and what you want the face to look like, and I examine the jaw: I ask you to clench while I feel the muscle, judge its bulk and where the thickest part sits, check for asymmetry, feel for the parotid gland and the facial artery at the front border, and pinch the skin over the angle to judge how much fat and how much laxity there is. Where the anatomy is unusual or a vessel is hard to locate, I map the muscle with ultrasound. Then I mark the safe zone: the lower third of the muscle, behind a line from the corner of the mouth to the ear, above the border of the jaw. Everything in front of that line is the smile muscles; everything above it is the parotid.

The treatment takes ten minutes. No anaesthetic is needed; the needle is very fine and each injection is a brief pinch. The dose is placed deep, into the belly of the muscle, at three to five points a side, usually 20 to 30 units a side for slimming and 25 to 40 for heavy grinders, with the strongest muscles occasionally needing more. Charging a flat fee rather than per unit means the dose is decided by the muscle, not by the price. There is no mark afterwards beyond an occasional pinpoint of blood.

You leave with written aftercare and my direct number. The review is at four weeks, when I re-examine the muscle and add a small top-up if one side is stronger than the other, at no charge. Repeat treatment is at four to six months at first, stretching to eight to twelve as the muscle shrinks. Masseter treatment combines with the Nefertiti neck lift for a jawline pulled down by the platysma, with chin filler to lengthen a face that is being slimmed, and with anti-wrinkle injections to the upper face in the same appointment.

“The masseter sits next to the muscles that make you smile and on top of the parotid gland. A lopsided smile after this treatment is not bad luck, it is bad mapping. I feel the muscle while you clench, mark the safe zone and inject deep and low, and I have never had to explain a crooked smile to a patient.”

Dr Chiké Emeagi, MRCS, GMC 4418489

MASSETER INJECTIONS VS THE ALTERNATIVES

How masseter Botox compares with other treatments for a wide jaw or grinding

Each row is an option patients ask me about. The realistic-result column is what I say in the room.

Option	What it does	Best for	Onset and duration	Downtime	Realistic result
Masseter Botox	Relaxes and shrinks the chewing muscle	Muscle-driven jaw width; grinding; jaw tension	Relief 10 to 14 days; slimming 6 to 8 weeks; lasts 4 to 6 months	None	A softer jaw angle and a quiet jaw; needs repeating, less often over time
Night guard from your dentist	A splint protects the teeth from grinding	Tooth wear; anyone who cannot have injections	Immediate protection; worn nightly	None	Saves the enamel; does not reduce clenching, tension or jaw size
Nefertiti neck lift	Relaxes the platysma bands pulling the jawline down	A blurred jawline and neck bands rather than a wide jaw	2 weeks; 3 to 4 months	None	A cleaner jawline; often combined with masseter treatment
Fat dissolving	Dissolves fat under the chin and along the jowl	Width that pinches as fat, not muscle	6 to 8 weeks per session; permanent for treated fat	Swelling for a week	Slimmer chin and jowl; no effect on muscle
HIFU or Sofwave	Tightens skin and, with HIFU, reduces fat	Laxity along the jawline; skin unmasked by slimming	12 weeks; 12 to 24 months	None	A firmer jawline; complements masseter treatment in the over-forties
Chin filler	Lengthens and projects the chin	A short chin making the jaw look wide	Immediate; 12 to 18 months	Swelling 2 to 3 days	A longer face that reads as slimmer; often combined
Surgical jaw reduction	Shaves the angle of the mandible	True bony squareness	Permanent	General anaesthetic; weeks	The only answer for bone; referred, not offered here

My blogs on how long masseter treatment lasts, how long it takes to work and what it costs go through the questions patients ask most.

TIMELINE

What happens week by week

The muscle relaxes before it shrinks. This is the course most patients follow after a first treatment.

Time	What is happening	What you notice	What to do
Day of treatment	Medicine binding at the nerve endings	Nothing; a pinpoint mark at most	Stay upright 4 hours; no rubbing, gym, alcohol or hard chewing for 24 hours
Days 3 to 7	Muscle contraction weakening	Clenching feels less forceful; chewing tough food takes more effort	Normal diet; note any change in your smile and tell me, it is rare and temporary
Days 10 to 14	Full relaxation	Grinding and jaw ache settle; morning headaches ease; partners notice the quiet	Nothing
Weeks 4 to 6	Muscle beginning to shrink from disuse	The jaw angle starts to soften; face looks slimmer in photographs	Four-week review; small top-up if one side is stronger
Weeks 6 to 8	Peak reduction	The full slimming result	Compare with baseline photographs
Months 4 to 6	Nerve endings recovering	Clenching gradually returns; muscle slowly regrows	Repeat treatment when you notice the tension coming back, not on a fixed date
After 3 to 4 treatments	Muscle smaller and habit weakened	Longer gaps between treatments, often 8 to 12 months	Maintenance

Around one patient in twenty notices chewing fatigue with very tough food in the first fortnight. It passes.

RESULTS

Results and what to expect

For grinding and clenching the result is quick and reliable: most patients report that the jaw feels lighter within a fortnight, that they wake without the ache, and that headaches that had been blamed on screens or stress stop. Dentists notice less wear at the next check-up. For slimming, the change is slower and more variable, because it depends on how much of the width was muscle. A thick, hard masseter that stands out when you clench can lose a centimetre of width each side over two or three treatments; a modest muscle over a broad jawbone changes less, and I say so at the consultation rather than at the review.

The honest expectations. The first treatment gives the biggest functional change and a moderate cosmetic one; the cosmetic result builds over the second and third. A face that is slimmed can look older if the skin over the angle was already loose, which is why I check skin quality first and sometimes recommend tightening alongside. A very small number of patients notice a change in their smile for a few weeks, which comes from the medicine reaching the risorius muscle and is avoided by injecting deep and low; a smaller number notice a bulge when they clench, from the deep fibres, which is treated by adjusting the placement next time. Chewing very tough food can feel tiring for a fortnight. None of these is permanent.

I photograph the jaw from the front and at 45 degrees before treatment, at the four-week review and at eight weeks, in the same light.

AFTER TREATMENT

Recovery, downtime and aftercare

The first four hours. Stay upright; no lying down, massage or leaning on the jaw. No hats or helmets pressing on the area.

The first 24 hours. No gym, sauna, alcohol or facials. Avoid very tough food: steak, crusty bread, gum, hard nuts. Pasta, fish, rice, chicken and vegetables are fine straight away.

The first two weeks. Nothing to avoid. If you notice any change to your smile, or a bulge when you clench, tell me; both are uncommon, temporary and useful for planning the next dose.

Bruising. Rare, because the injections are few and deep. If it happens, make-up covers it the next day.

You leave with written aftercare, the date of your four-week review and my direct contact details.

IS THIS FOR ME?

Is masseter Botox right for you?

The test is simple: clench, and feel the angle of your jaw. If a hard lump stands out under your fingers, the width is muscle and this treatment will change it.

A good candidate

A square or wide lower face where the muscle bulges on clenching. Teeth grinding, clenching, jaw tension, morning headaches or tooth wear. A jaw that has widened with stress or gum chewing. One masseter larger than the other. Men and women; any skin type.

Better with something first or alongside

Loose skin along the jaw, especially over forty-five: skin tightening alongside so slimming does not unmask jowls. A short chin: chin filler to lengthen the face. Neck bands blurring the jawline: the Nefertiti lift. Jaw pain with clicking, locking or limited opening: a dental or maxillofacial assessment first, because the treatment helps muscle pain but not a damaged joint.

Not suitable now

Pregnancy or breastfeeding. Neuromuscular conditions such as myasthenia gravis. Certain antibiotics and muscle relaxants, discussed at consultation. Infection at the site. A jaw that is wide because of bone, where the treatment will disappoint and I will say so.

PRICING

What masseter Botox costs in London

The fee is flat on purpose: charging per unit rewards under-dosing a muscle that is one of the strongest in the body, and an under-dosed masseter is a wasted treatment. Your fee is confirmed at consultation, once your treatment plan is agreed.

Treatment	What it does	Price
Masseter Botox, both sides	Jaw slimming, grinding, or both; dose to muscle bulk	£400
Four-week review and balancing top-up	Included	£0
Nefertiti neck lift, alongside	Platysma bands and jawline	See Nefertiti page
Chin filler, 1 ml, alongside	To lengthen a slimmed face	£350
Upper-face anti-wrinkle injections in the same appointment	Three areas	£300

Prices are from the clinic price list. My blog on the cost of masseter treatment explains the arithmetic. Your fee is confirmed at consultation, once your treatment plan is agreed.

WHY US

Why choose Hampstead Aesthetics for masseter Botox

The complications of this treatment are anatomical: a crooked smile from the risorius, a bulge from the deep fibres, a dry mouth from the parotid, a bruise from the facial artery. I am a GMC-registered doctor (4418489), a Member of the Royal College of Surgeons of Edinburgh and a GP with a master’s degree in aesthetic medicine, and before aesthetics I taught anatomy. I examine every jaw while you clench, mark the safe zone on the skin, use ultrasound where it helps, and inject every dose myself. The four-week review is where the dose is refined, and it is included because it is part of the treatment, not an extra.

The clinic is on West End Lane in West Hampstead, NW6, two minutes from West Hampstead Jubilee line, Overground and Thameslink stations. Patients come from Hampstead, Swiss Cottage, St John’s Wood, Belsize Park, Kilburn, Primrose Hill, Camden and across North and West London, and a good number come after a treatment elsewhere that changed their smile.

AT HOME

What makes the result last

Stop chewing gum, which is the single biggest driver of masseter bulk in people who do not grind. Notice daytime clenching: the teeth should be apart when the mouth is closed, and most clenchers hold them together at the desk without knowing. A dental night guard protects the teeth on the nights the treatment is wearing off and is worth having anyway. Manage the stress that drives the grinding; the treatment breaks the habit for months at a time, and patients who use that window to change the pattern need it less. A regular sleep routine and less alcohol at night reduce night grinding. Repeat treatment when the tension returns rather than on a schedule, and expect the gap to lengthen.

PATIENT REVIEWS

What patients say

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I usually get anti-wrinkle treatments and wouldn't trust my face in the hands of anyone else. From day one, Dr Chiké has been welcoming and thorough.

I had a great session here. Really friendly, knowledgeable and pain free.

I recently had treatment by Dr Chiké and couldn't be happier. The outcome is beautifully natural.

TRUSTED BRANDS

Clinically validated products we use

Botox is a registered trademark of AbbVie and a prescription-only medicine. The botulinum toxin products used for masseter treatment are licensed in the UK, supplied through their authorised distributors, and prescribed by me after a face-to-face consultation; the product and batch are recorded in your notes. Which product is used is a clinical decision made at that consultation.

WHO IS YOUR PRACTITIONER

Medical Governance & Practitioner Verification

Dr Chike Emeagi - GMC Registration No. 4418489

At Hampstead Aesthetics, every masseter treatment is carried out by Dr Chike Emeagi, a fully registered medical doctor and GP whose qualifications and licence to practise are publicly verifiable.

MRCGP - Member of the Royal College of General Practitioners
MRCS - Member of the Royal College of Surgeons of Edinburgh
MSc Aesthetic Medicine - Postgraduate master's degree in aesthetic clinical practice
GMC Licensed - Full licence to practise, verifiable on the public medical register
Former anatomy demonstrator; independent prescriber

You are encouraged to verify Dr Chike’s registration directly on the https://www.gmc-uk.org/doctors/4418489 GMC’s online medical register before booking. Any doctor practising without a valid GMC licence is doing so illegally.

DOCTOR LED TREATMENT

Why Doctor Led Matters

The masseter shares its corner of the face with the risorius and zygomaticus muscles that make you smile, the parotid gland and its duct, and the facial artery. Medicine placed too far forward reaches the smile muscles and the smile drops on one side for two to three months; placed too high it reaches the parotid; placed too shallow it does little to the muscle and more to the skin. In the UK the medicine is prescription-only, which means a prescriber must see you face to face before it is given, and a non-prescriber injecting it without that consultation is breaking the law. It is still routinely offered that way.

At Hampstead Aesthetics I am both the prescriber and the injector. I examine the muscle while you clench, mark the safe zone, use ultrasound where the anatomy is unclear, place every injection deep and low myself, and review you at four weeks.

YOUR SAFETY

Emergency Safety Protocols

Anaphylaxis kit on site — full adrenaline protocol for allergic reaction.
Hyaluronidase on site — reversal agent for hyaluronic acid filler and part of the vascular occlusion protocol.
ACE-certified practitioner — I hold emergency complication management certification.
999 escalation protocol — written procedures for emergency hospital transfer.

Every product and device is CE-marked and sourced from authorised UK distributors. The clinic holds full professional indemnity insurance covering all treatments.

CONSENT

Consent, Privacy & Your Rights

Before treatment you have a full written consultation covering medical history, contraindications, realistic outcomes and the specific risks of each treatment in your plan. Treatment only proceeds with informed, documented consent. If you have a concern, raise it with me directly; if it is not resolved, you can escalate to the General Medical Council.

Your consultation, treatment and review are all conducted by the same doctor. There are no hand-offs.

Reviewed September 2026. Dr Chike Emeagi, GMC No. 4418489. Regulatory position correct at date of review; licensing of non-surgical cosmetic procedures in England is subject to change.

FAQ's

Frequently Asked Questions

What is masseter Botox?

Masseter Botox is the injection of botulinum toxin, a prescription-only medicine, into the masseter muscle at the angle of the jaw to reduce its bulk and its overactivity. It slims a square jaw over six to eight weeks and relieves teeth grinding, clenching and jaw tension within two. Because it is a prescription medicine, suitability is decided at a face-to-face consultation with me as the prescriber, and the product and batch are recorded in your notes.

How long does masseter Botox take to work?

Grinding and clenching ease within ten to fourteen days, sometimes from day five. Visible slimming starts at around four weeks, because the muscle has to shrink from disuse rather than simply relax, and peaks at six to eight weeks. My blog on how long masseter treatment takes to work has the week-by-week detail.

How long does masseter Botox last?

Four to six months after a first treatment. The muscle regrows slowly once it has shrunk, so by the third or fourth treatment most patients are returning every eight to twelve months, and the slimming holds between visits. My blog on how long it lasts covers what shortens and lengthens it.

How much does masseter Botox cost in London?

Your fee is confirmed at consultation, once your treatment plan is agreed.

How many units do I need?

It depends on the muscle. A modest masseter being slimmed needs around 20 to 25 units a side; a heavy grinder 25 to 40; a very thick muscle occasionally 50. I decide by feeling the muscle while you clench, not from a chart, and the flat fee means the dose is never limited by the price.

Will it affect my smile?

Not if it is placed correctly. The smile muscles sit in front of the masseter, and injecting deep and low in the back third of the muscle keeps the medicine away from them. A change to the smile after treatment elsewhere is the commonest reason patients come to me for the first time; it is temporary, and the fix is better mapping next time.

Does it help teeth grinding and jaw pain?

Yes, and it is the main medical use. It reduces the force of clenching and grinding, which relieves jaw tension, morning headaches, tooth sensitivity and wear, and the aching over the joint. It does not repair a damaged jaw joint, so clicking, locking or limited opening needs a dental or maxillofacial assessment as well.

Will slimming my jaw make my face sag?

It can if the skin over the angle was already loose and a large muscle is shrunk quickly, which is why I pinch the skin and judge its elasticity before treating anyone over forty-five. Where laxity is present I treat more gradually and recommend tightening alongside, with Sofwave, HIFU or skin boosters.

Does masseter Botox hurt?

Barely. The needle is very fine, there are three to five injections a side and each is a brief pinch; most patients rate it one out of ten. No anaesthetic is needed and the appointment takes about ten minutes once the assessment is done.

Why is my jaw getting wider?

Usually because the masseter is growing with use: daytime clenching at a desk, night grinding, chewing gum, or a stress pattern that has become a habit. Weight gain adds fat over the angle and the two are easily confused, which is why I feel the muscle while you clench. Bone does not widen in adulthood. My blog on why your face looks wider goes through the pattern.

Can it be combined with a Nefertiti neck lift or chin filler?

Yes, and both are common. The Nefertiti lift relaxes the platysma bands pulling the jawline down and pairs with masseter treatment for a cleaner lower face. Chin filler lengthens a face that is being slimmed so the proportions stay balanced. Upper-face anti-wrinkle injections can be done in the same appointment.

Is masseter Botox permanent?

No. The medicine wears off over four to six months. The muscle does shrink with repeated treatment, so the gap between visits lengthens and the slimming becomes more stable, but if you stop entirely the muscle regrows over a year or so, particularly if the grinding returns.

Can I have it while pregnant or breastfeeding?

No. The medicine has not been studied in pregnancy or breastfeeding and I defer treatment until after. A night guard from your dentist protects the teeth in the meantime.

What about jaw or chin injections for a different problem?

All are assessed at the same consultation. Your fee is confirmed at consultation, once your treatment plan is agreed.

How soon before an event should I have it?

Six to eight weeks for visible slimming, two weeks for grinding relief. A first treatment is best done well before a wedding or a photographed event so that the four-week review has happened and any balancing is done.

Where in London do you offer masseter Botox?

At Hampstead Aesthetics on West End Lane, West Hampstead, NW6, two minutes from West Hampstead Jubilee line, Overground and Thameslink stations. Patients come from Hampstead, Swiss Cottage, St John’s Wood, Belsize Park, Kilburn, Primrose Hill, Camden and across North and West London.

Arrange your masseter consultation

If your jaw looks squarer than it used to, or aches, clicks or grinds, a consultation with me examines the muscle while you clench, tells you honestly whether it is muscle, fat or bone, and quotes a flat fee in writing. Patients come from West Hampstead, NW6 and across London. Related: Nefertiti neck lift, Chin filler, Jowls and sagging skin, Double chin.

VISIT US

Our London Clinic

Nearest Tube: West Hampstead (Jubilee Line) · 2 min walk

Overground: West Hampstead Overground · 3 min walk

Parking: Pay & Display on West End Lane

Proudly serving clients from:

West Hampstead · Hampstead · Primrose Hill · St John’s Wood · Belsize Park · Camden · Swiss Cottage · Finchley Road · Maida Vale · Queen’s Park · Highgate · Kentish Town

Reviewed by Dr Chiké Emeagi, MBBS, MRCGP, MRCS, GMC No. 4418489.

Last reviewed September 2026. This page is for information only and does not replace a medical consultation. Botulinum toxin is a prescription-only medicine; suitability is decided at a face-to-face consultation with a prescriber. Results vary between individuals and are not guaranteed. All treatments carry potential risks, which are discussed before any procedure. Before-and-after photographs show individual patients and do not guarantee identical outcomes. Prices are taken from the clinic price list at the date of review. Hampstead Aesthetics, 269 West End Lane, West Hampstead, London NW6 1QS.