Botulinum Toxin for Tinnitus: A Muscle-Based Treatment Review

A scoping review analyzing 284 records concludes there is a plausible anatomical and neurophysiological link between masseter muscle hyperactivity and somatosensory tinnitus. The analysis, led by Jacopo Gardellin and colleagues, suggests botulinum toxin type A (BoNT/A) could be a hypothesis-generating therapeutic option for this subtype, but it remains experimental and lacks sufficient direct clinical evidence.

Mapping the Connection: From Jaw to Ear

The concept of somatosensory tinnitus is not new, but its mechanisms are becoming clearer. This subtype describes tinnitus that can be modulated by movements or pressure on structures in the head, neck, or jaw. The review by Gardellin’s team synthesizes how hyperactivity in the masseter muscle—a primary jaw muscle used for chewing—could influence auditory perception. The pathway is not through the ear itself, but through complex neural networks. Sensory signals from the face and jaw converge with auditory signals in the brainstem and higher brain centers. When the masseter is chronically tense or overactive, it may send abnormal, increased signals along these shared pathways, potentially contributing to or worsening the perception of tinnitus.

This understanding aligns with other research exploring how cervical (neck) stimulation can affect hearing disorders, suggesting a broader link between the somatosensory and auditory systems. You can read more about these connections in our article on cervical stimulation effects on hearing disorders.

Scoping the Evidence: A Sparse Research Field

To assess the state of knowledge, the researchers conducted a systematic scoping review following PRISMA-ScR guidelines. They searched two major medical databases (MEDLINE and EMBASE) up to May 2026 using three distinct search strategies focused on BoNT/A and tinnitus, and on tinnitus and masticatory (chewing) dysfunction. From an initial pool of 284 records, only four studies met their strict eligibility criteria. Three came from the BoNT/A search line, and one from the masticatory dysfunction search.

This small number is telling. It confirms that while the biological rationale is strong, direct clinical research investigating targeted treatments like BoNT/A for masseter-related tinnitus is extremely limited. The team also identified one additional relevant clinical report (Ranoux and Levine, 2024) through a manual search, which described a protocol where tinnitus improved following BoNT/A injections in the periauricular (around the ear) and splenius capitis (neck) muscles. This same protocol suggested masseter or temporalis (temple) injections as an alternative approach.

Botulinum Toxin: A Theoretical Solution Awaiting Proof

Botulinum toxin type A is a well-established treatment for conditions involving muscle hyperactivity, such as cervical dystonia and bruxism (teeth grinding). Its proposed mechanism for somatosensory tinnitus is straightforward: by chemically relaxing the overactive masseter muscle, it should reduce the abnormal somatosensory input traveling to the auditory brain regions. This reduction in “noise” from the jaw could, in theory, diminish the tinnitus signal.

However, the review stresses that this remains theoretical for tinnitus application. The authors state plainly that “direct clinical evidence for tinnitus improvement remains insufficient.” The existing reports, including the one by Ranoux and Levine, are promising but anecdotal. They lack the control groups and standardized, blinded outcome measures required to prove efficacy and rule out placebo effects. This cautious perspective is consistent with a deeper examination of the topic, such as the one found in our dedicated review of the masseter muscle and botulinum toxin in tinnitus.

Practical Implications for Patients and Clinicians

The findings have clear, practical ramifications. For individuals whose tinnitus changes with jaw movement, clenching, or neck pressure, this review validates that their experience has a probable biological basis. It underscores the importance of a multidisciplinary assessment that includes dental or temporomandibular joint (TMJ) specialists alongside audiologists and otolaryngologists.

For clinicians, the message is one of cautious, informed experimentation. If BoNT/A is considered for a patient with suspected masseter-related somatosensory tinnitus, the authors insist it must be framed as a hypothesis-driven intervention. It should be administered within a structured clinical framework where outcomes are measured using validated tinnitus questionnaires and loudness matching before and after treatment. This approach turns an experimental treatment into a structured form of observation that can contribute to future knowledge.

The ultimate need is for prospective, randomized, placebo-controlled trials. Such studies are required to move BoNT/A from a plausible concept to an evidence-based treatment option. This step is common in the progression of hearing health research, where promising ideas—from novative drug delivery systems to new sound therapies—must pass rigorous testing before becoming standard care.

Source: This article is based on the scoping review “Botulinum Toxin for Masseter-Related Somatosensory Tinnitus: A Scoping Review on the Anatomical and Neurophysiological Rationale” by Gardellin, J., D’Angelo, M., & Spadotto, L. (2024). The full paper is available via DOI: 10.3390/toxins18070310.