A wide or square lower face and the clenching, grinding and tension of bruxism often share the same cause — an overactive, enlarged masseter muscle. What is right for you depends on whether the issue is the muscle, your bite, or both.
An enlarged, overactive masseter — from clenching and grinding (bruxism) or a naturally strong muscle
Common symptoms
A wide or square jaw, jaw tension and soreness, grinding, and tension-type headaches
Key areas
The masseter muscles at the angle of the jaw, both sides of the lower face
A square or wide lower face and teeth grinding (bruxism) are often two sides of the same problem: an enlarged, overactive masseter — the powerful chewing muscle at the angle of the jaw. Habitual clenching and grinding, or simply naturally strong muscles, can bulk it up, widening the jaw while also causing tension, soreness and tension-type headaches. Relaxing the muscle with botulinum toxin can soften jaw width and reduce clenching, but the right plan depends on whether the cause is muscular, dental or both — which is why a proper assessment comes first.
As seen in
Understanding the concern
What is Square Jaw & Teeth Grinding (Bruxism)?
The masseter is one of the strongest muscles in the body. It sits at the angle of the jaw and powers chewing and clenching, and like any muscle it grows with use. When it becomes enlarged — through habitual or vigorous chewing, persistent grinding, or simply a naturally strong, prominent muscle — it can widen the lower face and create a square, heavy jawline, sometimes with a visible bulge when you clench.
The same overactivity is closely linked to bruxism: involuntary teeth grinding and jaw clenching, frequently during sleep or under stress. An overworking masseter does not only change the shape of the face; it can leave the jaw feeling tense, tired or sore, contribute to tension-type headaches, and place repeated load on the teeth. So a square jaw and the discomfort of grinding often travel together, driven by the same muscle.
It is important to separate the muscular picture from everything else. A wide lower face can also come from bone structure rather than muscle, and grinding itself frequently has dental and behavioural causes — bite issues, stress and sleep patterns among them — that a dentist needs to assess. Understanding which factors are actually at play, and in what proportion, matters far more than reaching for any single treatment.
Relaxing the masseter helps only where width and grinding are driven by the muscle. A jaw that is wide because of bone will not change, and the dental side of grinding still needs a dentist — often a night guard. Dr Nina will say so plainly and refer where appropriate.
Quick reference
What causes it
An enlarged, overactive masseter — from clenching and grinding (bruxism) or a naturally strong muscle
Common symptoms
A wide or square jaw, jaw tension and soreness, grinding, and tension-type headaches
Key areas
The masseter muscles at the angle of the jaw, both sides of the lower face
What to consider
Whether the width is muscular or bony, and whether grinding also has dental or stress-related causes
Medical vs cosmetic
Botulinum toxin can address muscular width and clenching; dental causes still need a dentist, often a night guard
Why it happens — three drivers
Clenching & grinding
Persistent bruxism — often at night or under stress — overworks the masseter. Like any exercised muscle it enlarges, widening the jaw and leaving it tense, tired and prone to headaches.
Naturally strong muscle
Some people simply have a prominent, well-developed masseter without heavy grinding. The muscle bulk alone gives a square, wide lower face, more noticeable when the jaw is clenched.
Bite & dental factors
How the teeth meet, stress and sleep can drive grinding independently of muscle bulk. These dental and behavioural causes need a dentist’s input and are not addressed by relaxing the muscle.
Where it tends to show up
A wide or square-looking lower face
A visible bulge at the angle of the jaw when clenching
Jaw tension, tightness or soreness, often worse in the morning
Teeth grinding or clenching, especially during sleep
Tension-type headaches around the temples or sides of the head
Worn, sensitive or chipped teeth flagged by your dentist
At Facial Sculpting
What happens at your consultation
A consultation is not a commitment to treatment — it is a proper clinical assessment. Here is what to expect.
01
A full clinical assessment
Dr Nina examines the size and activity of your masseter muscles on each side, assesses whether your jaw width is muscular or structural, and reviews your grinding, clenching and tension symptoms alongside any headaches — so the plan addresses what is actually driving your concern.
02
An honest, specific plan
If relaxing the masseter is likely to help your jaw width and clenching, she will recommend it and explain the gradual timeline. Where grinding has a dental cause, or headaches suggest chronic migraine, she will say so — and refer to a dentist or frame a separate medical plan where that is the right route.
03
No obligation
Consultations are never upsells. The outcome may be a course of jawline slimming, a referral for a night guard, a separate migraine assessment, or simply honest reassurance. The goal is the right answer for your jaw and symptoms — not a booking.
What is the best treatment for a square jaw caused by muscle?
Where a square or wide lower face is caused by an enlarged masseter, Jawline Slimming is the most direct option. Botulinum toxin is injected into the masseter muscle on both sides to relax it so it works less forcefully; over repeated treatments the muscle gradually reduces in bulk and the jaw softens. The change is measured and develops over weeks rather than instantly. If your jaw is wide because of bone structure rather than muscle, this will not change it — which is why Dr Nina assesses whether the width is muscular or structural before recommending treatment.
Can a square jaw be slimmed without surgery?
If the squareness is driven by an enlarged masseter muscle, yes — relaxing the muscle with botulinum toxin (Jawline Slimming) can soften the jaw over time without surgery. The treatment is minimally invasive, takes only a few minutes and has minimal downtime. It works by reducing how forcefully the muscle contracts so it gradually slims with repeated treatment. It cannot reduce width that comes from the underlying bone, and the effect is maintained rather than permanent. Dr Nina will tell you honestly which category your jaw falls into at consultation.
How does jawline slimming help teeth grinding (bruxism)?
Bruxism — involuntary teeth grinding and clenching, often during sleep — is driven by an overactive masseter. By relaxing that muscle with botulinum toxin, Jawline Slimming reduces the force of clenching and grinding, which can ease jaw tension, soreness and associated tension-type headaches and help protect the teeth. Importantly, it addresses the muscular component only. Grinding frequently also has dental and behavioural causes — bite issues, stress and sleep among them — so this treatment works alongside a dentist’s input and a night guard rather than replacing them.
Does masseter botox stop teeth grinding completely?
Not necessarily. Relaxing the masseter reduces the force of grinding and clenching and can meaningfully ease the tension, soreness and headaches that come with it. But grinding is often multifactorial — driven partly by your bite, stress and sleep patterns, which the muscle relaxation does not address. For that reason it is best understood as treating the muscular component of bruxism, not a complete cure. A dentist’s assessment, and usually a night guard to protect the teeth, remain important. Dr Nina will explain honestly what the treatment can and cannot do for your symptoms.
Do I still need a night guard if I have masseter treatment?
In most cases, yes. A night guard and relaxing the masseter do different jobs: the guard physically protects the teeth from the damage of grinding, while botulinum toxin reduces the force of the muscle driving it. Because grinding often has dental causes that the muscle treatment does not address, jaw slimming complements a night guard rather than replacing it. Your dentist remains an important part of managing bruxism, and Dr Nina will say so plainly and refer where dental input is needed.
How long does it take to see jaw slimming results?
The two effects develop on different timelines. Relief from clenching, grinding and jaw tension is often felt within a few days. Visible slimming of the jaw is gradual — it builds over the following weeks as the masseter relaxes and reduces in bulk. Because the muscle slims further with repeated treatment, the aesthetic change can become more pronounced over a course of sessions. This is not an instant result, and Dr Nina will set realistic expectations of a measured change at your consultation.
How long does masseter (jaw slimming) treatment last?
The effect typically lasts around three to four months before the muscle gradually regains activity, so it is maintained rather than permanent. Repeat sessions every few months sustain both the slimmer contour and the relief from grinding. Over a course of treatments the masseter tends to reduce in bulk, so many people find the slimming becomes more established and that they can space sessions further apart over time. Exactly how long it lasts varies with the dose, your muscle size and your metabolism.
Why is my jaw square and my face wide at the bottom?
A square, wide lower face is commonly caused by an enlarged masseter muscle at the angle of the jaw. The muscle can enlarge through habitual or vigorous chewing, persistent grinding and clenching (bruxism), or simply because you have a naturally strong, prominent muscle. A bulge that becomes obvious when you clench is a typical sign that muscle is responsible. Width can also come from the underlying bone, however, which behaves quite differently — relaxing the muscle will not change bone. Dr Nina assesses which is driving your jaw shape before advising on treatment.
Is migraine treatment the same as jawline slimming?
No — they are separate treatments, even though both use botulinum toxin. Jawline Slimming targets the masseter to soften a wide jaw and ease clenching and grinding. Migraine Treatment is an established preventive protocol for diagnosed chronic migraine, given as a series of tiny injections across set points of the head, neck and shoulders to help reduce how often migraines occur. It is a medical treatment, appropriate only for genuinely chronic migraine and given after a medical assessment. Where jaw clenching contributes to tension headaches, jaw slimming may help that component, but it is not a migraine treatment.
Can jaw slimming help my headaches?
Where headaches are linked to jaw clenching and an overactive masseter — typically tension-type headaches around the temples — relaxing the muscle with Jawline Slimming can help reduce them by easing the underlying clenching. This is different from chronic migraine. If you have a diagnosed chronic migraine pattern, that is treated as a separate, dedicated Migraine Treatment, also using botulinum toxin but with a different injection protocol and only after a medical assessment. Dr Nina will assess your symptoms and advise which approach, or combination, is appropriate for you.
Who is migraine treatment with botulinum toxin suitable for?
Migraine Treatment is appropriate only for people with genuinely chronic migraine — broadly, headache on at least 15 days a month for more than three months, with migraine features on many of those days — and is used after a medical assessment. It is a preventive treatment intended to reduce how often migraines occur, not a cure and not a treatment for an acute attack. It is not suitable for occasional or episodic headaches. New, sudden or changing headaches need medical investigation first. Dr Nina takes a full headache history and confirms a chronic pattern before considering it.
Is jawline slimming safe, and does it affect chewing?
Botulinum toxin has been used safely in medicine for many years and is generally well tolerated. As a prescription medicine it is given only after assessment by a qualified practitioner who understands the jaw musculature. The dose is judged to relax the masseter enough to soften its action and bulk without preventing normal eating. Some people notice mild jaw fatigue or a slightly different chewing sensation in the first week or two while the muscle adjusts, which settles, and harder or very chewy foods may feel a little more tiring at first. Dr Nina discusses any less common risks at consultation.
Trusted by patients
What our patients say about Facial Sculpting
Real Google reviews from verified patients — unedited and unfiltered.
★★★★★
via Google
N
Nicky D.
★★★★★
"I am so thrilled with the results from my recent procedures with Dr. Nina. Initially I was prescribed a bespoke skin care plan using medical grade products from which I began to see immediate results. On Dr Nina’s advice I then returned for Botox, Profhilo and Endolift. She has such a wonderful Calm,friendly and reassuring nature that makes you feel completely at ease. The procedures were painless which is a definite credit to her skill and expertise. The results have been amazing..... I love the even texture and glow my (Menopausal) skin now has. My saggy jawline has disappeared leaving a firmer, leaner profile. Just wonderful... I can’t recommend Dr Nina and her Team highly enough."
S
Sophie J.Patient review
★★★★★
I had a fabulous experience with Dr Nina. I had a Botox treatment which was the best I’ve had. She was very thorough and took time and care during the treatment to tailor it to my exact needs. I will certainly be returning for more treatments! A true professional who really knows her stuff.
Verified patient
A
Ashley W.Patient review
★★★★★
I’m so happy with my results from the fantastic clinic. Nina and her team were fabulous. Thank you again!
Verified patient
L
Lucianna G.Patient review
★★★★★
I’ve seen Dr. Nina twice now for lip augmentation, and honestly I couldn’t recommend her enough! The care she took in ensuring she knew what I wanted, as well as keeping me safe was more than any other practitioner I have been with. I have superficial blood vessels, so I am more prone to having complications, and she explained this to me and took all the necessary measures to ensure I got fabulous results while still being safe. I know that I can always contact her if anything worries me and for me that is paramount. Coming from a medical background it’s difficult to find someone I can trust, and after meeting lots of facial aesthetics doctors/dentists I know that I’ll be sticking with her! Also, she gives very helpful information on her instagram and TikTok!
Verified patient
V
Vidhi P.Patient review
★★★★★
I’ve had a great experience with Dr Nina and her team. They’ve been very helpful in answering my questions and helping me put my skincare routine together. She has given me great suggestions and honest reviews about products and treatments suitable for my skin.
A square jaw and grinding are easy to over-simplify — and easy to over-treat. Dr Nina’s approach is to assess whether the width is truly muscular, judge the dose to your individual masseters, and be honest about where a dentist or a medical migraine pathway belongs instead of, or alongside, treatment.
Muscle or bone — assessed properly
Relaxing the masseter only helps if the width is muscular. Dr Nina checks whether your jaw is wide because of muscle or bone before recommending anything, so you are not treated for the wrong cause.
Honest about the dental side
Grinding often has dental and stress-related causes. We are clear that jaw slimming eases the muscular component but does not replace a dentist’s input or a night guard, and we refer where appropriate.
Measured, gradual results
A less-is-more philosophy: doses placed symmetrically for your anatomy, softening the jaw gradually over weeks and calming clenching — never an over-done or frozen result.
“In my practice, I focus on addressing life’s moments and the emotions they carry, rather than merely correcting lines and imperfections. I aim to provide therapies that respect and reflect the individual’s personal story.”
