Masseter Muscle Botulinum Toxin for Tinnitus

A scoping review of 284 records found only four studies that directly examined the connection between Botulinum Toxin Type A (BoNT/A) and tinnitus linked to jaw muscle activity. This scarcity highlights a significant gap between the strong theoretical rationale for the treatment and the clinical evidence to support it.

The Rationale: How a Jaw Muscle Could Affect Your Ears

The concept of somatosensory tinnitus proposes that structures in the head, neck, and jaw can influence the perception of sound through shared neural pathways. For a subset of patients, their tinnitus is not solely an auditory phenomenon but is modulated by the somatosensory system. The masseter muscle, a primary jaw muscle used for chewing, is a key area of interest. When this muscle is chronically tense or hyperactive—often due to conditions like temporomandibular disorder (TMD)—it can send abnormal signals into the central nervous system.

These signals may converge in brainstem areas like the dorsal cochlear nucleus, where auditory and somatosensory information is processed. This convergence can theoretically alter auditory neuron activity, contributing to or worsening the perception of tinnitus. This biological mechanism forms the basis for investigating treatments that target the masseter muscle. Our existing article, “TMD and Tinnitus: MMP3 Gene Links in Women”, explores another facet of the complex relationship between jaw disorders and ear symptoms.

Scoping the Evidence: A Search for Clinical Studies

To understand what clinical evidence exists, researchers Jacopo Gardellin, Marta D’Angelo, and Lorenzo Spadotto conducted a systematic scoping review. They followed PRISMA-ScR guidelines and searched two major medical databases, MEDLINE and EMBASE, up to May 2026. Their search used three complementary strategies focusing on BoNT/A and tinnitus, and on tinnitus and masticatory (chewing) dysfunction.

From an initial pool of 284 records, the process was stringent. Only four studies met the inclusion criteria. Three came from the BoNT/A search line, and one from the masticatory dysfunction search. An additional relevant report (Ranoux and Levine, 2024) was found through a manual search of references. This study described tinnitus improvement after BoNT/A injections near the ear and neck muscles, and suggested masseter or temporalis injections as an alternative approach within the same protocol.

Findings: Strong Theory, Weak Clinical Data

The review’s primary finding is the stark disconnect between theory and practice. The authors conclude that current anatomical and neurophysiological evidence “supports a plausible link” between masseter hyperactivity and somatosensory tinnitus. The biological pathway is considered credible.

However, the clinical evidence for using BoNT/A as a treatment is described as “insufficient.” BoNT/A is well-established for reducing muscle hyperactivity in other conditions, and it may theoretically reduce the abnormal somatosensory input from the masseter that could drive tinnitus. But the jump from this theoretical benefit to proven patient relief has not been made. The identified studies are few and lack the controlled, prospective design needed to draw firm conclusions. You can read a more focused analysis of this approach in our related piece, “Somatosensory Tinnitus: Botulinum Toxin Treatment Review”.

Practical Implications for Patients and Clinicians

For patients experiencing tinnitus that changes with jaw movement or clenching, this review underscores the importance of a multidisciplinary assessment. An evaluation by a dentist or TMD specialist may be necessary to identify a potential somatosensory component.

The authors are explicit in their recommendations: the use of BoNT/A for somatosensory tinnitus “should be considered experimental or hypothesis-based.” It is not a standard treatment. If explored, it must be done within a careful clinical framework that includes:

• A thorough diagnostic workup to confirm the somatosensory subtype.
• Clear, standardized measures of tinnitus severity before and after treatment (e.g., Tinnitus Functional Index).
• Administration by a clinician highly experienced in both BoNT/A injections and tinnitus management.

This cautious approach aligns with the need for more robust evidence, as also discussed in our article “Masseter Muscle Tinnitus: Botox Treatment Review”.

The Path Forward: A Call for Rigorous Trials

The definitive conclusion of the review is a call to action. “Prospective controlled trials are needed,” the authors state. Future research must move beyond case reports and small open-label studies. Well-designed randomized controlled trials (RCTs) that compare BoNT/A injections to a placebo (sham injection) in carefully selected patients with somatosensory tinnitus are the only way to determine if the treatment is effective.

Such trials would need to standardize injection sites (e.g., masseter vs. temporalis), dosages, and outcome measures. Until this high-quality evidence is produced, BoNT/A will remain a promising but unproven hypothesis for managing this challenging tinnitus subtype.

Source: Gardellin, J.; D’Angelo, M.; Spadotto, L. Botulinum Toxin Type A for Masseter-Related Somatosensory Tinnitus: A Scoping Review of an Emerging Approach. Toxins 2026, 18, 310.