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Wrinkle relaxers are considered the most popular and well-known treatments for lines and wrinkles – but did you know they can also be used to slim and contour the face? 

Jawline or masseter slimming with muscle-relaxing injections is one of our most requested treatments at our Sydney clinic. It reduces the appearance of an overly large, square or boxy jaw line, creating a slimmer, more V-shaped face. 

Injectable muscle relaxers work by weakening the masseter muscles of the jaw, effectively shrinking the muscles and in turn reducing the width of the lower face and achieving noticeable facial slimming. 

The masseter muscles are located at the back of your jaw and are responsible for chewing and clenching. Enlarged masseter muscles (masserteric hypoertrophy) are usually either genetic or as a result of excessive teeth grinding (bruxism). Injections into the masseter muscles using well-known wrinkle relaxers offers a quick, non-surgical solution to reduce a prominent jawline and sculpt the lower face.

Key benefits

  • Reduce the width of the jaw
  • Improve the appearance of a square or boxy jawline
  • Facial slimming
  • Create a more sculpted, V-shaped face
  • Non-surgical, minimally invasive
  • Quick, convenient procedure
  • Minimal discomfort and no downtime


You should start to see a noticeable slimming effect of your jawline around 4-6 weeks after your treatment, as the masseter muscles gradually weaken and reduce. Because these muscles are relatively large compared with the muscles around your eyes or forehead, results take longer to appear than crow’s feet or forehead line treatment. 

Initial treatment usually lasts around 3-4 months, however with repeated treatment many of our patients notice the results lasting longer.

Treatment Details

What to expect

Your Treatment Experience

Facial slimming with wrinkle relaxing injections is a straightforward procedure offering noticeable jawline slimming results.

You will first meet with our cosmetic doctor who will listen to your aesthetic goals and create a personalised treatment plan for you. If you are a good candidate for jawline slimming with wrinkle relaxers, your doctor will determine the correct dosage based on the size of your masseter muscles and extent of hypertrophy.

The treatment itself only takes around 10-15 minutes at our Sydney clinic and you should feel no pain. Most of our patients do not need a topical numbing cream as the injections are so quick. A series of injections using a fine needle are placed into both sides of your jaw muscles. If there is pre-existing asymmetry, your doctor may add more to one side to help improve any imbalance.

There is no downtime and you can continue your regular activity or return to work after your appointment. When performed by an experienced and skilled injector, complications are rare. The most common side effects are temporary redness, tenderness and possible bruising at the injection sites.

For more information on how wrinkle relaxers work, see our Wrinkle Relaxers page.

Your Questions Answered

Frequently asked questions (FAQs)

When will I see results?

It can take 4-6 weeks to see the results of your jawline slimming injections. As the masseter muscles are larger than the muscles targeted for facial wrinkle reduction, it takes longer for them to weaken and atrophy.

How long do results last?

It is normally 3-4 months before the masseter muscles return to their normal size. However, the duration of the effect often lengthens with each treatment. Many of our patients find they need less frequent injections over time.

How many jawline slimming treatments will I need?

Depending on the size and severity of your masseter muscle hypertrophy, you will need 1-3 treatments for optimal effects. 

Does it hurt?

Wrinkle relaxers into your jaw muscles feel much the same as forehead line or crow’s feet treatment. Usually icing the areas before treatment is enough, however we do offer topical numbing cream if you prefer. This is a low discomfort treatment and well tolerated by our patients.

Will jawline slimming injections interfere with my ability to chew or smile?

No, your ability to chew or smile should not be affected by wrinkle relaxing injections. 

Like any cosmetic procedure, in unqualified hands complications can occur. All of our practitioners at Pavilion Cosmetic Medical are certified, experienced and skilled in cosmetic injectable treatments. This greatly mitigates the risk for any side effects.

Can jawline slimming improve a round face as well?

Yes, in addition to improving the look of a square jawline, muscle relaxing injections can also minimise the appearance of a round face and add more definition to the lower face. It is particularly popular with our Asian patients.

What is the cost of jawline slimming?

The cost of jawline slimming is dependent on the size of your jaw muscles and the amount of wrinkle-relaxing product required. At your consultation, we will advise you on the correct dose to best match your expected results.


Interested in Jawline Slimming treatments?

We welcome you to Pavilion Cosmetic Medicine Sydney for a consultation with our cosmetic practitioners, who'll tailor a treatment plan specific to your concerns and desires.

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