May 2026

OTOLARYNGOLOGY

STUDY EVALUATES DIRECT VOCAL FOLD TESTOSTERONE INJECTIONS FOR VOICE MASCULINIZATION

While systemic testosterone therapy reliably lowers vocal pitch, some patients prefer to avoid systemic hormones due to concerns about side effects. Targeted laryngeal interventions that avoid systemic exposure could expand treatment options.
In two patients, Northwestern Medicine clinicians evaluated the safety and effectiveness of direct vocal fold testosterone injections as a localized approach to voice masculinization in testosterone‑naïve adults.
 
Study Details
  • Two nonbinary, testosterone‑naïve individuals seeking voice masculinization had undergone prior voice therapy but no systemic testosterone treatment.
  • Participants received four bilateral vocal fold testosterone injections at two‑week intervals.
  • Assessments were conducted before each injection and at one and three months after the final treatment. These included:
    • Acoustic voice recordings
    • Voice‑related quality of life surveys
    • Mood and anxiety questionnaires
    • Serum hormone levels pre‑ and post-treatment
 
Results
  • Both participants demonstrated a significant reduction in mean fundamental frequency at three months posttreatment.
  • Voice characteristics shifted toward prototypical male patterns.
  • Patients reported better voice‑related quality of life.
  • No systemic side effects were observed.
  • Posttreatment testosterone and estradiol levels remained comparable to baseline.
 
Clinical Implications
Larger longitudinal studies focused on this patient population are needed, but direct vocal fold testosterone injection may be a promising, minimally invasive option for voice masculinization in select testosterone‑naïve patients.
Andrew P. Stein, MD, Assistant Professor of Otolaryngology - Head and Neck Surgery

​Dr. Stein was a co-author of this study.

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