The Ins and Outs of Masseter Botox®

As far as facial aesthetics goes, botulinum toxin remains one of the most in-demand injectable treatments for clinics across the UK and beyond. In fact, according to Statista, the top non-surgical procedure worldwide in 2020 was Botox®.

Fast becoming one of the most popular cosmetic trends and known for its benefits relating to dental issues, interest in Masseter Botox® is very much on the rise. Whilst Botox® is typically associated with the forehead and the area between the eyebrows, you may be less familiar with Masseter Botox®, a treatment that relaxes the masseter muscle in the jaw. To catch you up to speed with this popular procedure, we’ve put together a comprehensive guide covering everything from the function of the masseter muscle to the procedure itself, including the consultation process, expected results, potential side effects and aftercare.

Botox®: the enduring patient demand

Botox® is a brand name for the neurotoxic protein botulinum toxin, an injection that works by inhibiting the release of acetylcholine from nerve cells in the brain and spinal cord. This weakens the targeted muscles, preventing them from contracting and causing paralysis that temporarily stops regular function for either medical or cosmetic purposes.

Botulinum toxin has been used by healthcare professionals throughout the world for over 50 years to treat a variety of medical conditions, including:

  • Excessive sweating (hyperhidrosis)
  • Uncontrollable blinking (blepharospasm)
  • Muscle spasms
  • Strabismus (crossed eyes)

After several decades of successful medicinal use, the U.S. Food and Drug Administration (FDA) approved the use of Botox® for cosmetic purposes in 2002. 

As a prescription medication, botulinum toxin can only be prescribed by a licenced professional and is typically administered by medics, including doctors, dentists and medical nurses. When used for cosmetic purposes, such healthcare professionals undergo aesthetics training and offer their services either in a dedicated aesthetics clinic or a similar clinical environment such as a dental practice.

What is Masseter Botox®?

Masseter Botox® is a procedure that relaxes the masseter muscle and reduces its size through injections of small amounts of botulinum toxin. The masseter muscle is large, triangular in shape and courses from the cheekbone to the jaw, making it essential for the proper function of the jaw. It is the primary muscle used for biting and chewing, as well as subconscious habits such as clenching and grinding of the teeth. Although it plays an important functional role, the masseter muscle also contributes significantly to the overall appearance of the lower third of the face, especially the jawline. 

Who is Masseter Botox for?

Aesthetic concerns in patients range from over-development due to hyperactivity, which can give the muscle a square appearance. Since squareness is typically seen as more masculine-looking, Masseter Botox® is particularly popular with women who desire a softer, slender and more feminine look. As a more general aesthetics treatment, botulinum toxin injections can reduce the size of the muscle and create a more defined jawline. The result is a more balanced profile and harmonious appearance that rejuvenates and relaxes the face.

Masseter Botox® is also extremely popular amongst patients with functional issues in the jaw and is well known for its ability to relieve pain and discomfort for these purposes. Medical and dental-related treatments include:

Bruxism – This condition occurs when a person involuntarily grinds or clenches their teeth, most often when sleeping or concentrating intensely. Bruxism is a fairly common issue, with Glamour Magazine recently reporting that over 6 million people in the UK grind their teeth. While the condition affects a large number of the population, many people aren’t aware of the significant problems it can lead to; from migraines to jaw pain and even tooth damage. Bruxism often stems from feelings of stress and anxiety but may also be caused by underlying dental or medical issues such as misaligned teeth or sleep apnea. For many people, the condition can be naturally resolved with a device such as a mouthguard or lifestyle changes like taking steps to manage stress and reduce tension. However, with more severe cases, patients are likely to be given medications or referred for Masseter Botox® treatment to eliminate teeth grinding.

Temporomandibular joint disorder – More commonly referred to as TMJ, this condition affects the movement of the jaw joint and the masseter muscle. According to BUPA, around one in ten people in the UK have a problem with their jaw joint. TMJ can be identified by a clicking or popping sound when the jaw moves to open and close the mouth, and may also lead to pain, discomfort or functional difficulties with biting or chewing. Other factors which can contribute to TMJ include stress, injury and occlusion (contact between the upper and lower teeth). Natural treatment for TMJ may include lifestyle changes similar to those recommended for bruxism, with the addition of cutting out hard or chewy foods. Patients who choose to undergo Masseter Botox® typically experience significant relief that the temporary relaxation of the masseter muscle provides, but in extreme cases, may require surgery to repair the jaw joint or even replace it entirely.

Who is it not suitable for?

As with any botulinum toxin procedure, there are several groups of people who may not be suitable candidates for Masseter Botox®. Some of these include:

  • Children: A new law introduced in 2021 (the Botulinum Toxin and Cosmetic Fillers (Children) Act) states that all patients undergoing Botox® for cosmetic purposes must be at least 18 years old. Reasons for this include the fact that muscles are still in the developmental stages and ethical concerns over minors’ emotional and mental maturity. That being said, physicians may prescribe botulinum toxins injections for the treatment of severe medical or dental issues in children.
  • Pregnant women: Since the effects of botulinum toxin on the developing baby are unknown, Botox injections should be avoided at all stages of pregnancy and during breastfeeding.
  • People with certain conditions or on certain medications: From nerve or muscle disorders to medication such as blood thinners, a wide range of medical-related factors deem some patients unsuitable for treatment. Such concerns are identified during the consultation and assessment stage of the process for those who may need to be made aware of their unsuitability.

Treatment benefits

When administered by a qualified medical professional, Masseter Botox® can deliver impressive results for both cosmetic and health-related purposes. Some of the most notable potential benefits of this injectable procedure include the following:

  • More feminine appearance: The injections relax the masseter muscle, which may reduce its size or make it appear less prominent. A square face becomes more oval-shaped for a slimmed-down feminine appearance that many consider more aesthetically pleasing.
  • Improved facial balance: Masseter Botox® can contribute to a more harmonious look and softens the patient’s face for a more balanced profile.
  • Bruxism or TMJ treatment: Both of these health issues can cause significant pain and discomfort that can affect an individual’s quality of life. Injections administered for the treatment of these concerns can provide instant relief that dramatically reduces aches, pains and irritation.

The non-surgical nature of Masseter Botox® is a huge benefit for many patients. With little to no downtime, no incisions and a much lower financial commitment than surgery, it offers a convenient and cost-effective treatment option.

The consultation process

The initial consultation is a crucial appointment that allows both patient and provider to ask and answer essential questions. At this stage, a complete patient medical and aesthetic history is obtained, as well as a physical examination of the face and jawline. Each step of this process is designed to determine that the patient is a suitable candidate for Botox®, address any concerns or doubts and develop a personalised treatment plan.

Although methods vary from clinic to clinic, a Masseter Botox® consultation is typically laid out as follows:

  1. Medical history – The practitioner asks questions related to pre-existing health conditions, any medication the patient is taking and a general overview of their health and lifestyle. This stage is similar to the questions a GP would ask during a healthcare appointment.
  2. Aesthetic history – The aesthetician needs to gain a complete understanding of any previous non-surgical treatments the patient has undergone, especially details of any adverse side effects or complications experienced.
  3. Risks involved – As with any minimally invasive procedure, several potential risks are associated with botulinum toxin injections. To best prepare the patient for the unlikely event that a complication occurs during or after treatment, the practitioner should explain all potential risks at the consultation stage.
  4. Expected results – Once the injector has identified the patient as a good candidate for treatment, it is important that they set realistic goals based on the patient’s desired result. This will ensure a higher level of satisfaction with the final outcome and allow time for the patient to discuss any aesthetic concerns they have or ask questions about the procedure.
  5. Informed consent – All patients must sign a consent form to undergo a Masseter Botox® treatment. This document should outline all of the elements discussed during the consultation appointment, including potential risks, pre-treatment advice and post-injection aftercare.

The procedure

While the process tends to vary depending on the aesthetics practice and chosen injector, the treatment itself generally doesn’t take very long but adheres to strict clinical and aesthetic guidelines for patient safety and the best results.

The step-by-step process typically involves:

  1. Preparation – Guidance on how to prepare for the aesthetics appointment is given at the consultation stage. Aestheticians usually advise patients to forego makeup or skincare products. Immediately before treatment, the practitioner will clean the area to be injected with an antiseptic solution.
  2. Injection – Although dependent on the treatment plan and individual patient, the injections are administered very quickly — typically taking no more than 15 minutes. Using a fine needle, the aesthetician injects a series of small doses of botulinum toxin into the masseter muscle to relax and temporarily paralyse the area. 
  3. Post-treatment information – The aesthetician will provide an aftercare guide and offer to answer any questions or concerns the patient has. Since the procedure is minimally invasive, there is no downtime, and the patient can proceed with their normal daily activities (provided they don’t interfere with aftercare guidance).


The initial results of a Masseter Botox® treatment can usually be noticed a few days after treatment, although it may take up to a week to appear. With further improvements over the days that follow, it generally takes around a fortnight for the full effects of the procedure to become apparent. Once the botulinum toxin has settled completely, the masseter muscle will relax and become temporarily paralysed, which may reduce the size of the muscle, provide a slimmer-looking jaw and create a more harmonious facial profile. For patients with dental or health-related issues, pain and discomfort associated with conditions such as bruxism and TMJ should also subside at this time.

The outcome of Masseter Botox® injections depends on several factors, including the level of muscle hyperactivity or overdevelopment, the dose of botulinum toxin administered and the patient’s facial structure and proportions.

Follow-up treatments

The results of Botox® injections are temporary and will fade over time, typically in around 3 to 4 months. As the botulinum toxin gradually dissolves, the muscle will begin to return to its original state, making top-up appointments necessary to maintain the desired effects. The frequency of follow-up injections is entirely up to the patient but is usually discussed with the practitioner during the consultation stage, with a treatment plan agreed upon at this time. While many patients choose to undergo a top-up at the earliest opportunity (every few months), some elect to take advantage of the flexibility and opt for less regular treatments.

Potential side effects

As with any non-surgical procedure, Masseter Botox® carries potential risks and side effects. The good news is that as a minimally invasive treatment, there is a low risk of complications and side effects are usually minimal, resolving on their own within a few days.

Potential side effects include:

  • Swelling, redness and bruising: Some or all of these side effects may appear on the area surrounding the injection site. All are perfectly normal and usually subside within a few days. A cold compress can provide relief, speed up recovery, and minimise discomfort.
  • Pain: You may experience mild discomfort or pain at the injection sites, which can be managed with over-the-counter pain medications such as paracetamol. Blood-thinning medications such as Ibuprofen should be avoided, as they can worsen symptoms such as bruising and swelling.
  • Headaches: Light headaches are normal and generally wear off after a few days, but severe migraines are rare. If headaches persist and worsen, you should seek immediate medical attention.
  • Serious side effects: Although rare, complications such as allergic reactions or infection may occur following treatment. The injector should ensure that the patient is fully aware of the risks involved and know the steps to take if extreme side effects are experienced.


Every clinic should have a dedicated aftercare guide for each treatment they offer, with details of steps to follow in the event of side effects and complications.

Specific post-treatment guidance for patients includes:

  • Avoid strenuous exercise for the first 48 hours after treatment.
  • Try to avoid touching your face or massaging the injection site, as this may affect the injections results and cause the botulinum toxin to spread.
  • Avoid exposing the injection area to direct sunlight or heat treatments such as saunas, sunbeds or steam rooms for the first 48 hours following treatment.
  • Sleep on your back with your head elevated to avoid disturbing the injection site.
  • Avoid alcohol for the first 48 hours following treatment. 
  • Keep your skin makeup-free for the first few days after treatment, and take a break from your regular skincare routine until the area has healed.
  • If you experience prolonged side effects, contact your practitioner for advice and to arrange a follow-up appointment. Or, in extreme cases, make your way to your closest A&E to seek medical attention.

Final thoughts on Masseter Botox®

With a considerable amount of potential benefits for patients, it is expected that the popularity of Masseter Botox® will continue to rise in the next few years. The results can be truly transformative if the injector is medically qualified and trained to administer aesthetic treatments. The non-surgical nature of the treatment offers a high level of convenience and flexibility, as well as a significantly lower financial commitment, making it a highly effective alternative to the more extreme and expensive option of surgery. Given the jaw function-related reasons that many people choose to undergo Masseter Botox®, it makes a fantastic addition to the treatment list of any aesthetics practice, offering invaluable opportunities for practitioners to expand their patient base and improve the quality of life of those who undergo treatment.

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