Botulinum Toxin for Tinnitus Masseter Muscle Therapy

A scoping review of 284 records has identified a plausible anatomical and neurophysiological link between masseter muscle hyperactivity and a specific subtype of tinnitus. The research, conducted by Jacopo Gardellin, Marta D’Angelo, and Lorenzo Spadotto, suggests botulinum neurotoxin type A (BoNT/A) could be a hypothesis-generating treatment for this “somatosensory tinnitus,” but stresses that direct clinical evidence remains insufficient.

## The Anatomical Link Between Jaw Muscles and Ear Perception

The central finding of the review is the strong biological rationale for a somatosensory subtype of tinnitus. This form is not generated solely within the auditory system. Instead, input from craniocervical and craniomandibular structures—like the muscles of the jaw and neck—can influence auditory pathways in the brain, changing or triggering the perception of sound.

The masseter muscle, a primary jaw-closing muscle, is a key player. Its hyperactivity, often related to bruxism (teeth grinding) or temporomandibular disorders, can create abnormal somatosensory signals. These signals travel to brain regions like the dorsal cochlear nucleus, where they may converge with and disrupt normal auditory processing. This convergence can theoretically amplify or generate the phantom sounds of tinnitus. This mechanism shares conceptual ground with other sensorimotor approaches to hearing disorders, such as the use of cervical stimulation for tinnitus and hyperacusis.

## Scant Direct Evidence for Botulinum Toxin as a Treatment

To assess the state of evidence for using BoNT/A—a potent muscle relaxant—the researchers conducted a systematic scoping review. They searched major medical databases (MEDLINE and EMBASE) using three complementary search strategies, with the last search dated 31 May 2026. From 284 records screened, only four studies met their eligibility criteria.

Three came from a search on “BoNT/A and tinnitus,” and one from a search on “tinnitus and masticatory dysfunction.” The authors also identified one additional relevant record (Ranoux and Levine, 2024) through a manual search. This study described tinnitus improvement following BoNT/A injections near the ear and in the splenius capitis neck muscle, and proposed masseter or temporalis injections as alternative sites in the same protocol.

The extreme paucity of eligible studies is the review’s most telling result. It confirms that while the theoretical connection is strong, high-quality clinical research directly testing BoNT/A for somatosensory tinnitus is virtually absent. A more focused look at this potential treatment can be found in our dedicated article, “Botulinum Toxin for Tinnitus: A Muscle-Based Treatment Review.”

## A Cautious, Multidisciplinary Path Forward

Given the lack of direct evidence, the authors are explicit: using BoNT/A for tinnitus should be considered strictly experimental or hypothesis-based. It is not a validated treatment. The toxin’s mechanism is well-established for reducing muscle hyperactivity, and it may theoretically reduce the aberrant somatosensory input believed to drive this tinnitus subtype. However, this theoretical benefit has not been proven in controlled clinical settings.

If BoNT/A is considered, the researchers argue it must be done within a multidisciplinary framework. This team should include audiologists, neurologists, otolaryngologists, and dentists or orofacial pain specialists. The goal is to ensure that patients with potential somatosensory tinnitus are correctly identified and that other contributing factors are managed. Standardized outcome assessments, like validated tinnitus questionnaires and psychoacoustic measurements, are essential to track any effect consistently.

This cautious, integrated approach mirrors the management strategy for other complex hearing-related conditions where multiple systems interact. For instance, the intersection of auditory and neurological symptoms is also a key feature in understanding the links between migraine and hearing disorders.

## The Clear Need for Prospective Controlled Trials

The conclusion from Gardellin and colleagues is unambiguous. While the anatomical and neurophysiological rationale connecting the masseter muscle to tinnitus is compelling, it remains a scientifically supported hypothesis. BoNT/A represents a logical candidate for testing this hypothesis because it directly targets the proposed source of the problem: muscle hyperactivity.

The definitive next step is prospective, controlled clinical trials. These studies must compare BoNT/A injections against a placebo (sham injection) in patients carefully screened for signs of somatosensory tinnitus, such as jaw dysfunction or the ability to modulate their tinnitus with head or neck movements. Only through such rigorous research can the field move from intriguing biological theory to evidence-based practice.

**Source Paper:** Gardellin, J., D’Angelo, M., & Spadotto, L. (2026). *Botulinum Neurotoxin Type A for Masseter-Related Somatosensory Tinnitus: A Scoping Review of Anatomical Rationale and Clinical Evidence*. Toxins. DOI: [10.3390/toxins18070310](https://doi.org/10.3390/toxins18070310)