Quick answer: How long does masseter Botox take to slim your face? The jaw muscle feels weaker within one to two weeks, but visible slimming usually appears at about four to six weeks, as the muscle gradually shrinks. The full effect is often seen around two to three months. Results commonly last four to six months, and repeat sessions can make them last longer.
Key takeaways
- Masseter Botox works more slowly than wrinkle Botox.
- Chewing may feel weaker within one to two weeks.
- Visible slimming usually starts at four to six weeks.
- The full result often appears at two to three months.
- Repeat sessions may make results last longer.
How does masseter Botox slim the face?
The masseter is the strong chewing muscle at the angle of the jaw. When it is large, often from chewing, clenching or genetics, the lower face can look wide or square. Botulinum toxin relaxes the muscle by blocking nerve signals. A relaxed muscle is used less, and over several weeks it becomes smaller, similar to how unused muscles shrink. This gradual reduction is what creates a slimmer, softer jawline.
Why does it take longer than wrinkle Botox?
Wrinkle Botox works by stopping muscle movement, so lines soften within a week or two. Jaw slimming depends on the muscle actually shrinking in size, which takes longer. The toxin starts working within days, but the visible change in face shape needs several weeks of reduced muscle activity.
Masseter Botox timeline
- Days 1 to 7: little visible change; the toxin starts working.
- Weeks 1 to 2: chewing may feel weaker, especially with hard foods.
- Weeks 4 to 6: visible slimming begins as the muscle shrinks.
- Months 2 to 3: the full slimming effect is usually seen.
- Months 4 to 6: the muscle gradually regains strength.
What affects how quickly you see results?
- Muscle size: very large muscles may take longer to shrink.
- Dose: an appropriate number of units is important for a visible effect.
- Clenching and grinding: strong habits may slow results.
- Diet: chewing gum or very tough foods can work against the effect.
- Face shape: if fat or bone contributes to width, results may be more subtle.
How long do results last?
After a first session, results commonly last about four to six months. With repeated treatments, the muscle may stay smaller for longer, and some people find they need treatment less often over time. Many doctors suggest a second session about four to six months after the first to build a stronger, longer-lasting result.
How can you support your results?
- Avoid chewing gum and very tough foods for a few weeks.
- Be aware of clenching during the day and try to relax your jaw.
- Ask your doctor about a night guard if you grind your teeth.
- Keep up repeat sessions as advised to maintain slimming.
How can you track your progress?
Changes in jaw width are gradual and easy to miss in the mirror. Take front and side photos before treatment, then again at four, six and twelve weeks in the same light and position. Many people notice the difference most clearly in photos, or when friends comment that their face looks softer and more balanced.
What if you do not see a change?
If your face does not look slimmer after about two months, talk to your doctor. The dose may need adjusting, or your lower face width may be due mainly to fat, sagging or bone structure. In that case, treatments such as fat reduction, lifting or filler for chin shape may be suggested alongside Botox.
Planning masseter Botox around your trip
Korea treated about 2.01 million foreign patients in 2025, and around 63% came for dermatology, according to the Ministry of Health and Welfare. Jaw slimming Botox is one of the most popular treatments for visitors. Because results take weeks, you will usually see the full change after you return home. If you have an event, plan treatment at least six to eight weeks ahead.
Frequently asked questions
Will I see slimming after one week?
Usually not. Slimming typically starts at four to six weeks.
Does masseter Botox affect my smile?
When placed correctly, it should not. Your doctor avoids nearby smile muscles.
Can I eat normally after jaw Botox?
Yes, though chewing hard foods may feel weaker for a few weeks.
How often should I repeat it?
Often every four to six months at first, then sometimes less often.
Sources
- Ministry of Health and Welfare, Republic of Korea – 2025 foreign patient statistics (press release, 2026).
- Ministry of Food and Drug Safety, Republic of Korea – botulinum toxin product approval information.
- Korean Dermatological Association – patient information on botulinum toxin.
This article is for general information only and is not medical advice. Results vary between individuals. Please consult a qualified physician before any treatment.
