Masseter Botox in Lisbon: Jawline Slimming and Bruxism Relief

Masseter botox is one of the fastest-growing aesthetic treatments in Lisbon — and for good reason. It works on two levels simultaneously: for people who grind their teeth, it reduces jaw tension and pain; for people who want a softer jawline, it gradually slims the lower face. This guide explains how it works, who it suits, and what you can expect.

What is the masseter and why treat it?

The masseter is one of the most powerful muscles in the human body — its primary job is chewing, but when it is chronically overactive (from teeth grinding, stress clenching, or genetic hypertrophy), it produces two visible effects: jaw pain and a wider, more square lower face.

Botulinum toxin injected into the masseter temporarily reduces the muscle's ability to contract with full force. The muscle does not disappear — it becomes less active. Over four to six weeks, reduced activity leads to modest volume reduction, which refines the jaw angle.

Who is it for?

Functional: bruxism and jaw pain. If you wake up with a sore jaw, headaches, or tooth sensitivity — or if your dentist has mentioned signs of grinding — masseter botox can significantly reduce the force of grinding contractions. It complements (but does not replace) a dental night guard.

Aesthetic: jawline slimming. If your lower face appears wide or square due to muscle bulk (not bone structure), botox can gradually narrow the jaw angle. Results are most visible in people with genuinely hypertrophied masseters — the treatment has limited effect when jaw width is purely skeletal.

A medical assessment before treatment determines which category you fall into and whether botox is the right approach.

What happens during the session

The session takes 15–20 minutes. The doctor palpates the masseter to locate the muscle bulk and identify injection points — typically two to four points per side. The injections use a very fine needle; most patients describe a momentary pressure sensation rather than pain. No anaesthesia is needed.

There is no downtime. You can return to normal activities immediately. Avoid very hard or chewy foods on the day of treatment as a precaution.

When do results appear and how long do they last?

Functional effects (reduced jaw tension, less pain from grinding) typically appear within one to two weeks. The aesthetic effect — visible reduction in jaw width — develops gradually as the muscle loses volume, reaching its maximum around six to eight weeks.

Effects last four to six months. The muscle regains strength before it fully regains volume, so the aesthetic result often outlasts the functional one. With regular maintenance sessions, the effect stabilises over time.

Masseter botox prices in Lisbon

Prices in Lisbon vary depending on the amount of product used. At Cosmo Clinic, masseter botox starts from €150, with the final price determined after the free initial assessment. The consultation is included — there is no charge to evaluate whether the treatment is appropriate for you.

Be cautious of very low prices: they may indicate less product (shorter duration), lower-quality product, or treatment by a non-physician. In Portugal, botulinum toxin injections must be performed by a licensed medical doctor.

Frequently asked questions

Does masseter botox hurt?

Most patients describe momentary pressure during the injections, not pain. No anaesthesia is needed and discomfort resolves immediately after the session.

Can I eat normally after the treatment?

Yes. Avoid very hard or chewy foods on the day of treatment as a precaution. From the following day there are no dietary restrictions.

How many sessions will I need?

Most patients see good results after a single session. Maintenance sessions every four to six months keep the effect stable. After several treatments, some patients find the interval can extend.

Is the procedure the same for bruxism and for aesthetics?

The injection technique is similar, but the dose may differ. Bruxism treatment focuses on reducing force; jawline slimming aims at volume reduction over time. Your doctor will calibrate accordingly.

Is Cosmo Clinic INFARMED registered?

Yes. All treatments at Cosmo Clinic are performed by licensed physicians registered with the Ordem dos Médicos. The clinic operates in compliance with INFARMED and ERS requirements for private health clinics in Portugal.

To book a consultation or see full treatment details — indications, process and pricing — visit the dedicated page: masseter botox at Cosmo Clinic. For more information about botox treatments in Lisbon, see our full botox treatment guide.