Jaw Botox: When Should You Go Back After It Wears Off?

When to repeat jaw Botox is better judged by your jawline than by the calendar. A few months after a first session, many people look in the mirror, think their jaw looks square again and wonder whether it has already worn off. How often you need it, and whether going back too often causes problems, are just as common questions.

This article explains the order in which masseter Botox works and wears off, when the effect tends to last, and how to gauge the right time for your next session.

In what order does jaw Botox work and wear off?

In what order does jaw Botox work and wear off?

Botox blocks the chemical messenger that carries the signal from nerve endings to the muscle. Without that signal, the muscle contracts less. The weakening usually starts two to four days after the injection and peaks around day 10. Any change in the jaw's volume comes later. Botox doesn't dissolve or cut away muscle; the volume shrinks only after the muscle has been used less for a while.

Over time, the nerve sprouts new branches and reconnects with the muscle. That reconnection is described as taking about three months. Once it's back, you start using the muscle again, and the volume that shrank while it rested gradually returns.

Masseter: the chewing muscle that runs from in front of the ear down to the angle of the lower jaw. When it's thick, the jawline looks square.

In what order does jaw Botox work and wear off?

How many months does it last, and when does it feel worn off?

How many months does it last, and when does it feel worn off?

A review that pooled masseter Botox studies found the peak effect around three months after a single session, with results lasting six to twelve months. The range is wide because the dose, muscle thickness and study groups all differed. There's also no single agreed-upon dose yet.

How many months does it last, and when does it feel worn off?

Chewing strength and jaw shape don't come back at the same pace. In a one-year study comparing 20 people who received 25 units in each masseter with 12 who weren't treated, bite force dropped clearly at three months and was no different from baseline at six months. The authors added that the visible change can last longer than that. It's worth keeping in mind that the study looked at a single injection of one product.

The time points in this table are rough groupings that combine the review, the study and the timeline of how the toxin acts. Chewing strength drops within days, but the jawline changes only as fast as the resting muscle loses volume, so it takes weeks. If your jawline looks the same a week or two after treatment, it's too early to decide it didn't work. On the other hand, the jawline sometimes holds for a while even after chewing strength comes back.

What should you judge your next session by?

What should you judge your next session by?

It's better to go by whether your jawline looks square again than by a date on the calendar. If the muscle just below and in front of your ear firms up and bulges when you clench, and your jawline looks close to your photos from before the first session, much of the effect has worn off. This is only a rough self-check; the real call is made at an exam.

Comparisons are easier if you take two photos in the same lighting and from the same angle as before treatment, one with your face relaxed and one with your teeth clenched. A big change in weight or a puffy day can also make your jawline look different, so it helps to note those days on the photos.

Very short intervals should be avoided. Rarely, the body develops antibodies to Botox that weaken its effect, and the risk rises with more frequent treatment, so one overview recommends not going back more often than every 8 to 12 weeks. That number is a minimum gap to avoid overly frequent treatment, not a schedule to follow. With repeated sessions, the muscle can gradually shrink and the time until the next session may lengthen.

A small study of six women treated three times at six-month intervals found masseter volume 12% smaller than before treatment one year after the third injection (from 26.39 cm³ to 23.26 cm³). Only six of the ten people originally enrolled finished, so the result is hard to generalize.

How STON Clinic approaches jaw Botox

How STON Clinic approaches jaw Botox

STON Clinic sees jaw Botox this way. Jaw Botox blocks the nerve signal to the masseter, the muscle you use to chew, so the muscle contracts less. A muscle that's used less can lose volume over time, which can make the jawline look slimmer. That's why the change may appear over several weeks rather than right after the injection. As the nerve signal gradually returns, the muscle is used again, so some people go back at intervals to maintain the result.

Swelling, redness, tenderness or bruising at the injection site are common reactions and usually settle within a few days. The following symptoms call for contacting the clinic right away rather than waiting.

• One corner of your mouth doesn't lift when you smile, or your smile looks uneven
• Trouble swallowing or slurred speech
• Difficulty breathing (in this case, go to the emergency room first)

At a consultation, starting with "Based on my last dose and date, how much has my muscle come back by now?" makes the next plan easier to understand. When you contact the clinic, include the date of your last session and a side-profile photo from before your first treatment.