Not loving the shape of your lower face? Think it’s too wide or boxy or even chubby – despite you being at your goal weight? You’re not imagining it, and the culprit is often the masseter – a strong, overworked muscle that can bulk up your jawline more than you realize.
It’s not something most people think about until they hear the words masseter Botox. Here’s everything you need to know about what it is, how it works, and why it might be the face-slimming solution you’ve been looking for.
What Is Masseter Botox for Facial Slimming?
First things first, a quick anatomy lesson. The masseter muscle is one of the strongest muscles in the human body. Located at the back of the jaw, near the mandible’s angle, it’s responsible for lifting your jaw when clenching, chewing, and speaking.
Because it’s so strong, the masseter is also quite large. Like any muscle, too much activity can make it grow in size, which can cause a whole array of problems—from cosmetic issues to headaches and tooth wear.
But not all masseter hypertrophy is caused by clenching. Some people have naturally stronger masseters and square faces, making them predisposed to muscle enlargement in that area.
Other factors that can enlarge the masseter muscle include teeth grinding, jaw clenching from stress, frequent gum chewing, and tension from muscle or dental imbalances.
Masseter Botox isn’t for everyone (because not everyone will have overactive muscles), but it works like a charm at relaxing this muscle just the right amount that it relieves tension and subtly changes your jaw shape—from boxy to more rounded and slimmed down.
Botox is a neuromodulator used for temporarily relaxing facial muscles to smooth dynamic wrinkles caused by expression and relax overactive muscles that cause unwanted effects. Other name brands include Jeuveau, Dysport, Xeomin, and Daxxify, and they all follow the same principle.
When injected strategically into the masseter muscle, Botox relaxes and weakens part of the muscle, leading to less bulge and a slimmer appearance. While it hasn’t been FDA-approved for this location, Botox is being used off-label to treat various conditions created or worsened by the masseter, and many studies have proven that its results are safe and predictable.
How Does Masseter Botox Work to Slim Your Jawline?
Once injected, Botox gets to work inside the masseters by relaxing them. You’ll start to notice less bulk from the first session. As the treatment repeats over time—just like when you stop going to the gym—your masseters will start to lose some mass, leading to an even narrower jawline.
This doesn’t mean your muscles are wasting away; they’re just losing that extra “oomph” they’ve been working so hard on. Here’s a timeline of results:
- Initial slimming: 2–4 weeks
- Peak contour: ~6 weeks
- Subtle reshaping over multiple sessions: Each treatment builds on the last, gradually refining your jawline.
Just like with other Botox treatments, many patients find they need fewer units over time, as the muscle adapts and maintains a slimmer profile.
How Long Will Your Results Last?
Masseter Botox results typically lasts around 3 to 6 months, though this can vary based on factors like metabolism and muscle strength. If you have genetically stronger masseters to begin with, you might burn through the neurotoxin faster.
To maintain your results, it’s generally recommended to schedule repeat treatments every 3 to 6 months. Go for whatever interval works best for you, but you shouldn’t wait until Botox effects wear off completely.
If you decide to stop treatments, the masseter muscles will gradually return to their original size and strength, and the jawline will go back to its previous look.
Who Injects Masseter Botox and What Happens in a Session?
Who handles your neurotoxin injections depends on whether it’s a cosmetic concern or a medical one. You’ll be seeing a cosmetic surgeon or injector trained in masseter Botox for face slimming, or a dentist or oral surgeon for bruxism/TMJ relief and tension headaches.
It’s absolutely crucial that you see a skilled injector when receiving masseter Botox. The masseter sits in a sensitive area, in relation to the parotid (main salivary gland) and risorius muscle (that controls the corners of your mouth when you smile). Injecting neurotoxin too forward or too high can cause some unpleasant side effects.
As with all Botox treatments, a session is quick and relatively pain-free. Here’s a quick walkthrough of what to expect:
- Consultation: Your provider will examine your jawline, discuss your goals and assess if you’re a good candidate for the procedure.
- Marking: The injection sites are marked for precision, targeting the lower half of the masseters.
- Numbing: A numbing cream may be applied to minimize discomfort.
- Injections: Botox is injected in target areas, deep into the masseter muscles.
- Aftercare: Minimal downtime; you can resume normal activities shortly after.
Typical dosage starts at 15 units per side, and can go up to 25–30 units based on muscle size and goals. For first-timers, it’s best to start slowly to factor in diffusion and how you’ll react to the neurotoxin. You may need a follow-up in 2–4 weeks to assess results and determine if a top-up is needed.
Masseter Botox Aftercare: What to Keep in Mind
The main goal after your Botox session is to help the neurotoxin stay exactly where it was placed. For the first 24 hours, it’s all about avoiding anything that could make it migrate or break down too soon.
Stick to soft foods and keep jaw movement gentle. Try not to overdo it with talking, laughing, or chewing — just let the area relax.
Avoid chewing gum, facial massages, intense facial workouts, or any big expressions for the day. Steer clear of heavy drinking too, since it can increase the risk of bruising.
It’s also best to stay upright for at least 4 to 6 hours post-treatment. That means no lying down, no long naps, and no bending over for extended periods.
Skip workouts, hot yoga, and saunas for the day — anything that makes you sweat or increases blood flow to the face can interfere with results.
Lastly, hold off on facials, gua sha, lasers, or skin tools for a few days. Give your face some quiet time to let the Botox settle in smoothly.
Benefits Beyond Slimming: Bruxism, TMJ, and Headache Relief
Let’s talk about some extra perks you might enjoy after getting masseter Botox. If you’ve been grinding your enamel like it’s your job, you’ll likely notice your bruxism all but disappear within 1–2 weeks—along with those annoying morning headaches. Your teeth will thank you, and your dental work will hold up way better.
Botox can also do wonders for TMJ pain. The masseter works alongside the temporalis and pterygoid muscles, forming an intricate network that helps your jaw move and rotate. When those muscles get out of sync, the TMJ (your jaw joints) can start acting up with symptoms like pain, clicking or locking.
If you have TMJ issues, it’s best to see a dental professional before jumping into Botox, since it’s a complex condition that needs comprehensive treatment.
Botox is also calming for overall tension caused by clenching this powerful muscle, making it a great add-on to support stress management, tension headaches, and that tight, tense feeling in the lower face.
Masseter Botox Side Effects: What You Might Notice
Botox in the masseter is a medical procedure, and like any treatment, it comes with risks and side effects. Most are mild and related to the injection itself — like bruising or tenderness. Others have more to do with how the muscle responds over time.
Common:
- Mild chewing weakness (around 30% of patients notice this)
- Light bruising at the injection site (~2.5%)
- Headaches (~0.6%)
Less common:
- Smile asymmetry or drooling if the injection is placed too far forward
- Paradoxical bulging — where parts of the muscle shrink unevenly, giving a slightly wavy jawline
- Hollow cheeks or early jowling if the muscle shrinks too much and no longer supports the tissue above it
Rare:
- Dry mouth (if the parotid gland is accidentally affected)
- Very subtle speech changes
The most common effect is mild chewing fatigue, especially with harder foods. This usually fades quickly, as the rest of your masseter and nearby muscles adjust and take over.
Smile asymmetry is another one to watch out for. It’s why your injector needs to place Botox carefully — not too far forward, and not unevenly from side to side (unless they’re correcting an existing imbalance). The risorius muscle, which helps lift the corners of your mouth, sits right next to the masseter and is easy to hit if someone isn’t familiar with facial anatomy.
Most patients are happy with their results. When people stop getting masseter Botox, it’s usually because of cost, or because they didn’t love how it changed their smile. If you don’t like your results, rest assured that effects are temporary and should wear off within a few months.
Masseter Botox vs. Buccal Fat Removal
If you’re looking to slim your face, you’ve probably come across buccal fat removal too. But here’s the thing: they’re very different treatments — and the results are not interchangeable.
Buccal fat removal is surgical. It takes out the fat pads in your cheeks to create a more hollowed, chiseled look. It can be great for some people, but it’s permanent — and in many cases, it can actually age the face long-term, especially if you already have a naturally lean or angular look.
Masseter Botox, on the other hand, works by gently slimming the lower face through the relaxation of an overactive jaw muscle. It doesn’t remove fat. It softens the width of the jaw — which can make your cheekbones pop without making you look gaunt. In fact, keeping a bit of roundness in the cheeks tends to look fresher, younger, and more balanced overall.
Treatments to Pair with Masseter Botox
Masseter Botox does the heavy lifting when it comes to slimming the lower face — but pairing it with the right cosmetic treatments can take you to the next level. If you’re going for lift, balance, or just want to keep things tight as your jaw contour softens, these are worth considering.
- Dermal fillers
Once your jawline slims down, the rest of your face might need a little rebalancing — especially if the cheeks or chin start to feel less defined in comparison. Fillers can add back subtle structure, contour the midface, and keep your features looking harmonious. - RF (Radiofrequency) Microneedling
When the muscle shrinks, some patients may notice mild laxity in the lower face. While not everyone gets jowls, if you’re prone to them or already seeing early signs, skin tightening through RF Microneedling can help keep things firm and lifted. - Sculptra
Perfect if slimming the jaw makes the midface feel a little flat or tired. Sculptra builds collagen over time, adding subtle volume and support — especially in the cheeks or temples.
FAQs on Masseter Botox
Can masseter Botox subtly reshape my lower face over time?
Yes — but it’s not a one-and-done. The first time you get Botox in your masseters, you’ll see the muscle start to relax after a few weeks. But the real magic happens after a few sessions, as the muscle mass gradually goes down from underuse. That’s when you’ll notice a slimmer, more rounded face and a narrower jawline.
Will treating just one side throw off my facial balance?
Not if it’s done correctly. If your asymmetry is caused by one overactive masseter, treating just that side can actually restore balance — which is the goal. That said, most people are treated evenly unless there’s a clear imbalance. Trust your injector’s eye and experience.
Does masseter Botox make cheekbones look more prominent?
It can. If you already have defined cheekbones, relaxing the masseters can help them stand out more. But in some cases, if the masseter was giving structure to the lower face, slimming it too much can lead to a slightly sunken or hollowed look. It really depends on your facial anatomy and a skilled injector will take that into account.
Can it help reduce a gummy smile?
Not directly. A gummy smile is usually caused by an overactive upper lip muscle — not the masseter. Some people do notice a subtle improvement after masseter Botox, but it’s more of a bonus side effect. If correcting a gummy smile is your goal, you’ll want Botox placed above the lip instead.
Could it affect my chewing strength or speech?
Mild chewing fatigue is normal. We’re intentionally relaxing this muscle, so things like chewing steak or tough bread might feel like more work, especially at first. But other nearby muscles will step up, and many people find that eating softer food, or more mindfully actually helps.
Can masseter Botox treat TMJ beyond bruxism?
It can help, and it does provide relief — but it’s not the full solution. TMJ dysfunction is complex and often tied to bite issues and jaw alignment. Botox can ease the tension, pain, and spasms in the masseter, but it’s treating the symptoms, not the root cause. A dental evaluation is still key for proper TMJ treatment.
Ready for a Slimmed Jawline?
Call us or click below to book your personalized masseter Botox consultation at The Luxe Room. Available in Denver, Boulder, and Fort Collins. Let’s find the contour that feels like you.
Sources
- Fortes, J., Pontes, F., Santos, A., et al. (2014). Lower facial remodeling with botulinum toxin type A for the treatment of masseter hypertrophy. Anais Brasileiros de Dermatologia, 89(6), 970–977. Retrieved from https://www.scielo.br/j/abd/a/RfBqLvYw35xjdBFgfmPtFHS/?lang=en&format=html
- Zhao, Y., Li, S., Chen, H., et al. (2020). Complication rates of masseter muscle botulinum toxin injections: Analysis of 2,036 cases. Journal of Cosmetic Dermatology, 19(11), 2966–2971. Retrieved from https://onlinelibrary.wiley.com/doi/10.1111/jocd.12473
- Yates, C., & Yen, Y. (2020). Refining toxin treatment in the masseters. In Botulinum Toxin in Aesthetic Medicine (2nd ed., Chapter 18). Taylor & Francis. Retrieved from https://www.taylorfrancis.com/chapters/edit/10.1201/9781003008132-18/refining-toxin-treatment-masseters-yates-yen-yu-chao
