How much does testosterone deepen voice pitch for trans men?

The effects of sex hormones on the vocal cords are a one-way process: male-typical levels of testosterone, whether from natal puberty in those assigned male or from the administration of testosterone in trans men, produces growth and thickening of the vocal cords and a corresponding drop in pitch (Schneider & Courey, 2016). The later use of testosterone blockers and estrogen by trans women who’ve already undergone natal puberty cannot reverse these changes to the vocal cords, and voice feminization for trans women can involve vocal and speech exercises directed toward producing a more feminine-sounding voice (Gelfer & Van Dong, 2013), as well as vocal surgery to alter the structure of the vocal cords and reduce their testosterone-induced growth (Schwarz et al., 2017).

In light of the challenges faced by trans women and transfeminine people in attaining a female-typical voice, many have expressed an assumption that trans men and transmasculine people will tend to have an “easier” experience in achieving their desired voice due to the effects of testosterone. But this is not necessarily the case: the influence of testosterone on voice can vary significantly between individual trans men, and not all trans men will develop a male-typical voice solely from testosterone.

Ziegler et al. (2018) conducted a meta-analysis of studies on the effects of testosterone on trans men’s vocal fundamental frequency, a measure of pitch. Pitch appears to be the most significant factor in whether a voice is categorized by listeners as that of a man or woman (Dacakis, 2002), with cis women  having an average speaking pitch of 225 Hz and cis men having an average speaking pitch of 125 Hz.

Ziegler et al. sought to quantify the proportion of trans men who, after at least one year of testosterone treatment, had not achieved a fundamental frequency less than or equal to 131 Hz. Analyzing the findings of 19 published articles which included 520 participants, the authors found that 21% of these participants did not experience a lowering of their fundamental frequency into the typical cisgender male range. Moreover, based on studies measuring participants’ evaluation of how congruent their voice was with their gender (indicated by endorsement of items such as “too high/feminine”, “not low/masculine enough”, “I worry my voice will reveal my native sex”, and “my voice does not reflect the true me”), the authors estimated that 21% did not feel their voice was fully congruent with their gender even after taking testosterone. Their analysis of overall satisfaction with voice following testosterone therapy found that 16% were not completely satisfied with their voice.

Previous studies have also found greater variability in fundamental frequency among trans men following testosterone treatment compared to cis men (Cosyns et al., 2013):

Nygren et al. (2016) similarly reported: “Final F0 values for trans men were congruent with reference values from vocally healthy Swedish males after 12 months of androgen treatment, although the variation was considerable.”

Even when testosterone hasn’t produced the desired decrease in pitch, trans men still have options for vocal masculinization. Ziegler et al. acknowledge that “voice therapy may be necessary to improve satisfaction with voice function and quality”, and 24% of participants in Nygren et al. were reported to have received vocal therapy for reasons such as “vocal fatigue, vocal instability, strain, hoarseness, problems projecting the voice, insufficient lowering of F0, and/or problems with the voice sounding too young.” Additionally, there are vocal cord surgeries that can reduce the fundamental frequency (Hoffman et al., 2014). The bottom line: Testosterone alone does not produce a male-typical vocal pitch for a surprisingly large proportion of trans men – and it would certainly be a mistake to assume that anyone’s transition is “easy”. ■