Facial slimming with Botox® has become one of the most requested non-surgical procedures for people who want to soften a square or wide jawline. This treatment is particularly effective when jaw width is caused by masseter muscle hypertrophy, a condition where the chewing muscles, located along the sides of the jaw, have become enlarged.
By carefully injecting Botox into these muscles, the skilled providers at Northwest Face & Body can reduce the bulk over time and create a slim and more tapered lower face. Our providers are highly trained in injecting Botox, making the procedure minimally invasive and offering customized results based on your facial structure and goals.
Understanding the Masseter Muscle and How Botox Works
The masseter muscle is one of the strongest in the human body. It’s responsible for chewing and clenching, and in some people, it can become naturally thick as a result of genetics, teeth grinding, frequent gum chewing, and clenching from stress.
When this muscle enlarges, it can make the face appear broader or more square-shaped. Botox works by gently reducing the muscle’s activity, which, over time, causes the muscle to shrink slightly in size. It relaxes the muscles enough to slim the jawline.
Why Units Matter in Botox Treatments
Botox is measured in units, meaning small, standardized doses that allow your injector to control the effect very precisely. The number of units you need isn’t about a one-size-fits-all formula; it’s about matching your muscle size, jaw strength, and aesthetic goals. Injectors at Northwest Face & Body are trained to inject Botox and can help calculate the correct dose for you.
Typical Dosage Ranges for Jaw Slimming
For Botox® (onabotulinumtoxinA), the most common dosage range per side of the face is:
- Mild hypertrophy: 20 to 25 units
- Moderate hypertrophy: 25 to 35 units
- Marked hypertrophy: 35 to 50 units
In patients with very thick masseters (common in men), the dose can go up to 60 units per side. These doses are typically split into 3 to 5 precise injection points per side.
Factors That Influence Your Dose
Your provider will assess multiple factors before deciding on the exact number of units:
- Muscle bulk and activity: Larger or stronger muscles need higher doses.
- Facial proportions: The dose is planned to maintain overall balance.
- Desired effect: Subtle softening requires fewer units; dramatic contouring requires more.
- Previous Botox treatments: Returning patients often need less to maintain results.
- Gender differences: Men usually require more than women for the same slimming effect.
- Skin and facial volume: Thinner skin or volume loss may require a more conservative approach.
What to Expect After Treatment
Botox treatment is usually non-invasive and requires minimal downtime. Here’s what you should expect after your treatment:
Immediately after:
- Small bumps or redness at injection sites
- Mild swelling or tenderness that fades within hours
First 3–7 days:
- The muscle begins to relax; chewing may feel slightly lighter.
Weeks 2–4:
- The slimming effect becomes noticeable as the muscle starts to reduce in size.
Weeks 8–12:
- Peak results: the jawline appears slimmer, softer, and more contoured.
Safety and Considerations
While Botox for jawline slimming is considered safe, it’s not suitable for everyone. Your provider will avoid treatment if you:
- Have a current infection in the treatment area
- Are pregnant or breastfeeding
- Have certain neuromuscular disorders
- Are allergic to any ingredients in the product
Temporary side effects may include mild chewing fatigue, slight smile changes, or asymmetry if the muscle relaxes unevenly. These usually resolve over time or can be corrected at follow-up.
Aftercare Tips
These are the aftercare instructions you should follow after getting Botox treatment:
- Avoid rubbing or massaging the treated area for 24 hours
- Remain upright for at least 4 hours after treatment
- Skip strenuous exercise and hot environments for the first day
- Attend your follow-up appointment to review results and symmetry
The Bottom Line
Most people need 20–50 units of Botox per side for jawline slimming, but your exact dose will be unique to your anatomy and goals. The best results come from a customized plan, careful technique, and follow-up adjustments if needed.
If you’re considering Botox for jawline slimming, a consultation at Northwest Face & Body will ensure your treatment plan is tailored to your unique features and goals. Our experienced injectors combine precision and safety to help you achieve a naturally refined look.
Schedule a consultation with one of our providers by calling us at (425) 546-0854. You can also contact us via our contact form or our Price Simulator™ app.
Additional Reads:
Why Does Botox Make Your Forehead Shiny?
Top 7 Things Not To Do After Botox
Daxxify vs. Botox: Which Is the Better Choice for Wrinkle Reduction?
