Most providers use 60 to 120 units of Dysport per side of the masseter, for a total of 120 to 240 units across both sides of the jaw. The exact number depends on the size of your masseter muscle, whether you’re treating for cosmetic slimming or jaw clenching, and how your body has responded to previous sessions. First-time patients typically start at the lower end of that range, with doses adjusted upward in follow-up treatments if needed.
Dysport is dosed differently than Botox, which is a common source of confusion. The conversion ratio is roughly 2.5 to 3 units of Dysport for every 1 unit of Botox. Since Botox masseter treatments typically range from 25 to 50 units per side, the equivalent Dysport dose lands in that 60 to 120 unit per side range.
Why Dosing Varies So Much
The masseter is one of the strongest muscles in the body, and its size varies significantly from person to person. Someone with mild jaw tension and a naturally narrow face needs far less product than someone with pronounced masseter hypertrophy, where the muscle has thickened over years of clenching or grinding. Providers assess muscle bulk by having you clench your jaw and feeling the muscle’s thickness and width before deciding on a dose.
Your treatment goal also matters. If you’re primarily looking for relief from bruxism or TMJ discomfort, a lower dose may be sufficient to relax the muscle without dramatically changing your face shape. If you want visible jawline slimming, higher doses are often needed to reduce the muscle volume enough to alter your facial contour. In clinical studies on masseter reduction, patients showed a 32% increase in satisfaction with their lower face and jawline by 12 weeks, with measurable volume loss that continued to improve over that period.
How the Injections Work
Dysport temporarily blocks nerve signals to the masseter, preventing it from contracting at full force. Over weeks of reduced activity, the muscle gradually shrinks, much like any muscle that isn’t being used. This is what produces the slimming effect along the jawline. Research shows a significant drop in masseter stiffness within three weeks of injection, and the muscle continues to lose volume over the following months.
Most providers use a multi-point injection technique, distributing the total dose across three to six points within each masseter. The injection sites are carefully positioned within a “safe zone” bounded by a line from the ear to the corner of the mouth at the top, and staying at least 1.5 to 2 centimeters above the lower jawline to avoid the nerve that controls your lower lip.
What the Timeline Looks Like
Don’t expect instant results. Dysport in the masseter works on a slower timeline than forehead or crow’s feet injections because you’re waiting for an entire muscle to atrophy, not just relax.
- Week 1: Little visible change, though some people notice their jaw feels slightly less tight when clenching.
- Weeks 2 to 3: The face starts to feel softer. Chewing tough or chewy foods may require slightly more effort.
- Weeks 6 to 12: Peak slimming becomes visible, especially from the front and in your side profile.
Results from a single session typically last 3 to 4 months before the muscle gradually regains its strength and volume. However, the real transformation happens with repeated treatments. Most people need two to three initial sessions spaced three to four months apart to fully condition the masseter. After that, maintenance sessions every four to six months can sustain the results, and some people find they need less product over time as the muscle stays smaller.
Risks to Know About
The most notable side effect specific to masseter injections is an asymmetric smile. This happens when the product spreads from the masseter into the risorius, a thin muscle that sits right on top of the front portion of the masseter and helps pull the corners of your mouth when you smile. If Dysport diffuses into the risorius, one side of your smile may not lift as high as the other, or you might temporarily lose a dimple.
This risk is higher when injections are placed too far forward on the muscle or too close to the skin’s surface. Experienced injectors position the needle deeper, beneath the layer of fat and into the thick part of the masseter itself, to minimize spread to surrounding muscles. The effect is temporary if it does occur, resolving as the Dysport wears off, but it can last several weeks.
Other possible side effects include mild soreness at the injection sites, slight difficulty chewing very hard foods in the first few weeks, and occasionally a feeling of jaw fatigue. Significant chewing problems are uncommon at standard cosmetic doses.
First Session vs. Follow-Up Doses
A conservative provider will often start with 60 to 80 units per side for your first treatment, then evaluate your results at a follow-up visit around six to eight weeks later. If the slimming or symptom relief isn’t where you want it, they can increase the dose at your next session. This approach reduces the chance of over-treating, which can leave the jawline looking overly narrowed or cause more pronounced chewing difficulty.
If you’ve had Botox in your masseter before and are switching to Dysport, your provider will convert your previous dose using the 2.5 to 3:1 ratio as a starting point. Someone who responded well to 30 units of Botox per side would typically begin with about 75 to 90 units of Dysport per side. Keep in mind that Dysport tends to spread slightly more than Botox after injection, which can be an advantage for covering a large muscle like the masseter but also means precise placement matters even more.