5 Subtle Signs Your Masseter Muscle May Be Overdeveloped and Why It Matters
A wider jawline can develop gradually and for a variety of reasons, including genetics and daily habits. One often overlooked cause is masseter hypertrophy, or the enlargement of the masseter muscle, a key muscle involved in chewing and clenching.
Although this change may not be immediately noticeable, over time it may contribute to a heavier lower face, facial asymmetry, or jaw discomfort for some individuals.
Below, we explore five subtle signs that could suggest your masseter muscles are overactive, along with current clinical insights on how registered healthcare professionals may approach this concern.
1. Morning Jaw Tension or Tightness
Experiencing jaw tightness, soreness, or fatigue upon waking may be associated with night-time clenching or grinding, also known as sleep bruxism. Over time, repeated activation of the masseter muscle during sleep can lead to muscle thickening.
A 2023 review in Aesthetic Surgery Journal Open Forum identified bruxism as a functional contributor to masseter hypertrophy, particularly among individuals unaware they clench their jaw during stress or sleep (Wu, Zeng, & Wu, 2023).
2. Gradual Broadening of the Lower Face
Some individuals notice their lower face becoming broader or more square-shaped over time, despite stable body weight. If the jawline appears more prominent, especially when clenching, it may be due to muscular changes rather than fat or bone development.
Differentiating between bone structure, fat deposition, and muscle activity is important. Imaging tools such as ultrasound or MRI can support this assessment (MDPI, 2023).
3. Habitual Chewing or Clenching During the Day
Frequent behaviours such as chewing gum, biting objects, or clenching when concentrating or stressed can increase load on the masseter muscle. Similar to other muscles, consistent use can cause hypertrophy.
These behaviours, though often overlooked, may influence facial proportions over time (Nilesh et al., 2021).
4. Clicking or Popping in the Jaw Joint
Clicking, difficulty opening the mouth, or jaw discomfort during function may be associated with stress on the temporomandibular joint (TMJ). Although not exclusively caused by the masseter, overactivity of this muscle can contribute to these symptoms.
Such concerns should be evaluated by a qualified practitioner to determine the underlying cause (Sharma, 2024).
5. Visible Muscle Activation When Clenching
When gently clenching the jaw, a noticeable firm or raised area near the angle of the jaw may be the masseter muscle. If one side is more prominent than the other, this may suggest hypertrophy or asymmetry.
While not always problematic, any discomfort or concern about facial balance should prompt a clinical review.
Clinical Options That May Be Considered
If a registered health practitioner determines that the masseter muscle is contributing to functional discomfort or facial imbalance, options that may be considered include:
Behavioural modification (e.g. reducing chewing or clenching habits)
Night guards for management of bruxism
Stress management techniques
Botulinum toxin type A (BoNT-A), following individual clinical assessment
BoNT-A may be used to reduce muscle activity and volume where clinically indicated. According to Gewargis (2025), the MSFIT approach is one technique used to address both function and facial balance in selected cases.
All treatment options should be discussed thoroughly with a qualified practitioner. Clinical decisions must be based on individual assessment and informed consent, and outcomes may vary.
Considering a Clinical Assessment
If you have noticed changes in your jawline or experience symptoms such as clenching or jaw tension, a consultation with a registered healthcare provider is recommended. At TT Aesthetics, our experienced team offers personalised assessments to determine whether treatment is appropriate for your needs.
To learn more about your masseters book a consultation with a qualified expert, book TT Aesthetics.
Citations
Gewargis, J. (2025). Treating masseteric hypertrophy with botulinum toxin A: The MSFIT technique. Aesthetic Nursing, 14(2).
MDPI. (2023). Dynamic quantitative imaging of the masseter muscles in bruxism patients. Journal of Personalized Medicine, 13(10), 1467.
Nilesh, K., Dharamsi, R., Patil, P., & Mate, P. (2021). Management of unilateral idiopathic masseter muscle hypertrophy with botulinum toxin type A. BMJ Case Reports, 14(1), e239056.
Sharma, R. (2024). Masticatory muscle hypertrophy. Radiopaedia.
Wu, Y., Zeng, D., & Wu, S. (2023). Botulinum toxin type A for the treatment of masseter muscle prominence in Asian populations. Aesthetic Surgery Journal Open Forum, 5.
