Evaluation of the Effects of Testosterone on Voice in Transmasculine Adolescents and Young Adults.

Abstract

Prospectively evaluate longitudinal voice changes in transmasculine adolescents and young adults (AYAs) initiating testosterone therapy. AYAs assigned female sex at birth and naïve to testosterone and voice therapy were prospectively enrolled prior to hormone initiation and followed for 12 months. Fundamental frequency (F₀) during sustained vowel and connected speech, pitch range, and cepstral peak prominence smooth (CPPs) were measured monthly. Patient-reported outcome measures analyzed include VHI-10, Transgender Voice Questionnaire (TVQ), and PROMIS Anxiety and Depression scales. Fifteen individuals enrolled; 14 (mean age [SD] = 18.43 years [4.31]) completed 12-month follow-up for analysis. Speaking F₀ decreased at 3 months (mean -32.9 Hz, p = 0.033) and plateaued by 9 months (p < 0.01). Sustained vowel F₀ decreased earlier at 2 months (p = 0.036). Semi-tone pitch range showed no significant change across 12 months (p = 0.47). CPPs in connected speech decreased significantly from baseline at 3 months (p = 0.047) and improved but remained significantly lower than baseline at nine (p = 0.010) and 12 months (p = 0.003). VHI-10 transiently worsened at 3 months (+3.14, p = 0.033) but returned to baseline by 9 months (p = 0.42). TVQ improved significantly from baseline (51.3) to 12 months (26.5; p = 0.002). PROMIS Anxiety decreased (p = 0.018), while Depression did not (p = 0.56). Testosterone therapy in transmasculine AYAs results in progressive lowering of F₀ beginning at Month 2 and stabilizing by Month 9, with improved voice-gender congruence and anxiety. This is the first prospective study with a substantial adolescent cohort, providing critical data that strengthens understanding of testosterone-related voice changes and informs best practices in gender-affirming voice care.