Masseter Botox Dosage: How Many Units Are Needed for Jawline Slimming?

Dr Hasaneen Al Janabi MBBS MRCS (ENT) - Dr Hass Clinic Founder & Medical Director

Published by Dr Hasaneen

Published date 23.02.26

Masseter Botox is one of the most effective non-surgical treatments for jawline slimming, teeth grinding, and facial contouring. One of the most common questions patients have is: “How many units of Botox will I need?”

At Dr Hass Clinic, we tailor every Masseter Botox treatment to your individual anatomy, muscle strength, and aesthetic goals. Understanding dosage helps patients set realistic expectations, optimise results, and maintain safety.

Masseter Botox Dosage: How Many Units Are Needed for Jawline Slimming

How Botox Works in the Masseter

The masseter is the main chewing muscle, located at the back of your jaw. Botox works by temporarily relaxing this muscle, which leads to:

  • Reduced jaw clenching and teeth grinding (bruxism)
  • Gradual slimming of the jawline over several weeks
  • Improved facial symmetry and proportion

The amount of Botox needed depends on muscle size, strength, and desired effect, which is why there is no single standard dose.

Where are the Masseter Muscles

Typical Dosage Range

For jawline slimming in adults, the average dosage per side typically falls between 20–40 units, although some patients may require slightly more or less. Key points to note:

  • Mild slimming / small masseters: 20–25 units per side
  • Moderate slimming / average masseters: 25–35 units per side
  • Significant muscle hypertrophy / very strong masseters: 35–40+ units per side

Note: These are approximate ranges. Only a qualified injector can determine the precise dosage based on a personalised assessment.

Masseter Botox (Masseter Reduction) Before and After Results - Dr Hass Clinic London

Factors That Influence Dosage

The dosage used for Masseter Botox can be influenced by:

1. Muscle Size and Thickness
Thicker, stronger masseters need more units to achieve noticeable slimming. Muscle size is assessed by palpation and visual observation of the jawline at rest and during clenching.

2. Desired Degree of Slimming
Some patients want subtle contouring, while others want a more dramatic narrowing. Conservative dosing reduces the risk of over-relaxation and uneven results.

3. Previous Treatments
Patients who have had prior Botox may require fewer units because the muscle is already partially relaxed. Repeat treatments are adjusted based on previous response.

4. Facial Symmetry
Slight differences between the left and right masseter muscles may require asymmetric dosing to achieve balance. Symmetry is critical for a natural-looking jawline.

5. Gender and Age
Men often require slightly higher doses due to stronger jaw muscles. Age may influence muscle strength and skin elasticity, affecting how the dosage is calculated.

Injection Technique and Dosage Distribution

Proper injection technique is essential for effective results and minimal side effects:

  • Multiple injection points: Typically 2–4 per side to evenly distribute the toxin
  • Depth of injection: Into the bulk of the masseter muscle, avoiding superficial placement
  • Unit allocation: Units are divided across the injection points for consistent relaxation
  • Safety considerations: Avoids diffusion into nearby muscles (e.g., risorius or platysma), which could affect chewing or smile

What Happens After Injection

After treatment, patients may notice:

  • Mild tenderness or swelling at injection points
  • Softening of the jaw muscle in 1–2 weeks
  • Gradual slimming of the lower face over 4–8 weeks
  • Maximum effect typically at 6–8 weeks, lasting 4–6 months

Tip: It is important to avoid massaging or applying pressure to the area immediately after treatment to prevent uneven distribution.

Safety and Personalisation

Masseter Botox is highly safe when performed by a qualified practitioner:

  • Only use medical-grade Botulinum toxin
  • Dosage is calculated according to muscle strength and aesthetic goals
  • Over-relaxation can lead to temporary weakness when chewing; conservative dosing prevents this
  • Follow-up checks at Dr Hass Clinic ensure results are symmetric and natural-looking
Filler Consultation at Dr Hass Clinic

Why Choose Dr Hass Clinic for Masseter Botox

At Dr Hass Clinic, every Masseter Botox treatment is:

  • Doctor-led: Administered by Dr Hasaneen Al Janabi, GMC-registered and Royal College of Surgeons member
  • Personalised: Dosage is customised for your jawline, muscle size, and desired contour
  • Followed up: Routine checks ensure optimal results and allow adjustments if necessary
  • Safe: Minimal downtime, predictable results, and natural aesthetics

Your treatment is not “one-size-fits-all.” Personalised dosing and precise injection technique are what make Masseter Botox both effective and safe.

Key Takeaways

  • Typical dosage per side: 20–40 units depending on muscle size and goals
  • Factors influencing dosage: muscle strength, symmetry, gender, age, prior treatments
  • Multiple injection points are used for even muscle relaxation
  • Results develop gradually over 4–8 weeks and last 4–6 months
  • Personalised dosing and follow-ups are essential for safety and natural results

Latest News

Don’t Take Our Word For it…

EXCELLENT
Trustindex star 1Trustindex star 2Trustindex star 3Trustindex star 4Trustindex star 5
Based on 334 reviews
Posted on Google Google
Will Blackwell profile picture
Will Blackwell
7 days ago
Google star 1Google star 2Google star 3Google star 4Google star 5Trustindex verifies that the original source of the review is Google.
10/10 so happy with results!!!! Would definitely recommend. With Dr Hass
Posted on Google Google
S G profile picture
S G
10 days ago
Google star 1Google star 2Google star 3Google star 4Google star 5Trustindex verifies that the original source of the review is Google.
I had my Endolift treatment with Dr Hass and couldn’t be happier with my experience. From the initial consultation through to the treatment itself, I felt reassured and well looked after. Dr Hass was professional, knowledgeable and took the time to explain everything clearly, which made me feel at ease throughout. I wanted a subtle, natural-looking result rather than anything drastic, and I felt confident that Dr Hass understood exactly what I was hoping to achieve. The whole experience was positive, and I’m really pleased with the care and attention I received. I would highly recommend Dr Hass to anyone considering Endolift and looking for a professional, reassuring experience.
Posted on Google Google
samira Fleur profile picture
samira Fleur
13 days ago
Google star 1Google star 2Google star 3Google star 4Google star 5Trustindex verifies that the original source of the review is Google.
Dr Hass is a guarantee of excellence. He consistently meets expectations by delivering beautiful, natural-looking results. His professionalism, expertise, and attention to detail make you feel confident that you are in the best hands. I couldn’t recommend the clinic more highly!
Posted on Google Google
Nikol Rosenbergova profile picture
Nikol Rosenbergova
13 days ago
Google star 1Google star 2Google star 3Google star 4Google star 5Trustindex verifies that the original source of the review is Google.
I recently went to Dr. Hass at Dr. Hass Clinic for an Endolift treatment, and I honestly couldn't be happier with the results! I had quite a bit of sagging skin, especially around my neck and lower face. The moment the procedure was done, I could immediately feel the tightening effect. The results were amazing right away the sagging on my neck completely disappeared, and my facial contours were lifted instantly. Dr. Hass is wonderful, so kind, and extremely professional. He explained everything in detail and took his time to focus precisely on the sagging areas where I needed it the most. I am so satisfied with my experience, I will definitely come back in the future, and I highly recommend him to anyone struggling with similar issues. He is truly one of the best, and I am so glad I found him and chose him!
Posted on Google Google
Zoe Lee profile picture
Zoe Lee
13 days ago
Google star 1Google star 2Google star 3Google star 4Google star 5Trustindex verifies that the original source of the review is Google.
Dr Hass is very professional and gentle during the procedure and very great follow up when I get in contact with him for advice. Also the clinic itself is very nice tidy and clean so Highly recommend!
Posted on Google Google
Zoya Fiaz profile picture
Zoya Fiaz
14 days ago
Google star 1Google star 2Google star 3Google star 4Google star 5Trustindex verifies that the original source of the review is Google.
I had my nose filler done by Dr. Hass, and I couldn’t be happier with the results! His knowledge, expertise and attention to detail were evident straight after the treatment. He understood exactly what I wanted to achieve and delivered the results I was hoping for. He also took the time to guide me through the process and advise me on the best approach to suit my nose and desired outcome. I’m extremely happy and satisfied with my results and would highly recommend Dr. Hass to anyone considering aesthetic treatments.
Posted on Google Google
Baylie-Bleu M profile picture
Baylie-Bleu M
15 days ago
Google star 1Google star 2Google star 3Google star 4Google star 5Trustindex verifies that the original source of the review is Google.
Visited today and had an amazing service and generally felt So comfortable, treatment was explained properly and we picked together which was best suited for my skin Very happy and will 100% recommend
Posted on Google Google
Lia Maria profile picture
Lia Maria
24 days ago
Google star 1Google star 2Google star 3Google star 4Google star 5Trustindex verifies that the original source of the review is Google.
I 100% recommends visiting Dr Hass clinic. Dr Hass is very friendly and a pro at what he does. I got facial balancing and he took his time analysing my face, I’m super happy with the results, very natural looking!
Posted on Google Google
Maya Ansar profile picture
Maya Ansar
29 days ago
Google star 1Google star 2Google star 3Google star 4Google star 5Trustindex verifies that the original source of the review is Google.
A very good experience. Dr Hass was professional, thorough and took the time to assess my face properly. The face mapping was very detailed, everything was explained clearly, and the recommendations felt considered rather than rushed. I felt very comfortable throughout.
Posted on Google Google
Lekaa Saleh profile picture
Lekaa Saleh
31 days ago
Google star 1Google star 2Google star 3Google star 4Google star 5Trustindex verifies that the original source of the review is Google.
I am a lady in my early 50s I was very confused to choose a clinic that can remove my double chin which was really annoying me and making me lose my confidence. I finally found Dr. Hass clinic. I am a person who doesn’t like surgeries or injections.. I was very worried but Dr Hass was a very experienced professional doctor who made me feel comfortable and relaxed. I personally didn’t feel any pain and when I saw the result I was amazed with the beautiful change … No more double chin 🥹🥹 It’s very important for all women to invest in their health and beauty.. I strongly recommend Dr Hass clinic and I would love to make another visit for different treatments 😊 Dr Hass you really changed my life by increasing my self confidence thank you so so much for everything 🥹🙏🏼🌹
Posted on Google Google
Ambar Mirza profile picture
Ambar Mirza
35 days ago
Google star 1Google star 2Google star 3Google star 4Google star 5Trustindex verifies that the original source of the review is Google.
I’ve been coming to Dr Hass for a long time now and I honestly wouldn’t trust anyone else with my filler. He always makes me feel completely at ease and really takes the time to listen to what I want, while also giving genuinely helpful and honest advice. He’s brilliant at what he does, couldn’t recommend him enough!
Posted on Google Google
jenai douglas profile picture
jenai douglas
36 days ago
Google star 1Google star 2Google star 3Google star 4Google star 5Trustindex verifies that the original source of the review is Google.
I visited Dr Hass for dermal fillers and it was my best experience to date. Dr Hass took time during the consultation to really ask questions to understand my needs and make the best recommendations for me to achieve my desired results. He was honest and personable and even advised me against treatments I thought I needed due to seeing others have these procedures online. He really cared about my results and being satisfied over anything else. I was nervous but he put me at ease and the results are amazing. Cannot recommend the clinic enough and I will be back!
Posted on Trustindex Trustindex
Nikol profile picture
Nikol
37 days ago
Trustindex star 1Trustindex star 2Trustindex star 3Trustindex star 4Trustindex star 5Trustindex verifies that the original source of the review is Trustindex.
Endolift A huge thank you to Dr. Haas! I had a big issue with sagging skin, especially on my neck, so I decided to get an Endolift for my face with an extended neck treatment. I saw the results immediately after the procedure—my skin was tightened, my facial contours were much more defined, and everything looked so beautiful and natural. I am extremely satisfied, the clinic is clean and gorgeous, and everyone there is so kind. Dr. Haas is truly one of the best doctors, and I highly recommend him to everyone!
Posted on Google Google
lola ri profile picture
lola ri
37 days ago
Google star 1Google star 2Google star 3Google star 4Google star 5Trustindex verifies that the original source of the review is Google.
Dr Hass is truly magical! He has an incredible eye and knows exactly what your face needs to create the perfect contour while keeping everything natural and beautifully balanced. His skill and attention to detail are exceptional I couldn’t be happier with the result. I highly recommend him!
Posted on Trustindex Trustindex
Caroline Wingfield profile picture
Caroline Wingfield
44 days ago
Trustindex star 1Trustindex star 2Trustindex star 3Trustindex star 4Trustindex star 5Trustindex verifies that the original source of the review is Trustindex.
Lips I would thoroughly recommend Dr Hass and his clinic. He is incredibly thorough, professional and, most importantly, honest in his approach. Having visited a number of different clinics over the years, what really sets Dr Hass apart is his focus on achieving a softer, fresher and more natural look rather than making you look “done”. He has completely transformed years of previous lip filler for me, and my lips already look amazing — beautifully natural and so much better balanced. I’ve had so many people notice the difference and comment on how good they look. I couldn’t be happier with the results and wouldn’t hesitate to recommend him.

Our clients’ satisfaction is at the heart of everything we do. We take immense pride in helping individuals enhance their natural beauty and boost their confidence.

Dr Hass Surgeon-led Aesthetic Clinic Mayfair Waiting Area Dr Hass Clinic - Luxury Aesthetic Clinic Mayfair

Our Clinic

Your Sanctuary

Welcome to our clinic, where innovation, expertise, and personalised care merge to redefine your natural beauty. We specialise in providing a wide range of non-invasive treatments that deliver remarkable results without the need for surgery.

Call us — 020 8168 8178

or

Speak To Us