Eli Smiley's two-year testosterone update, fact-checked

What did @eli.smiley3 actually say?

The video is a compilation of voice recordings captured at specific milestones: day one on testosterone, five months, one year, and two years. The creator says "this is my voice" at each stage, letting the audio progression speak for itself. There are no verbal medical claims, no dosage recommendations, and no promises about what testosterone will do for anyone else. It is personal documentation, not medical advice.

The transcript is garbled by auto-captioning, which rendered "testosterone" as "Test Dogs" and compressed some phrases. The actual content is a straightforward before-and-after voice journal that many trans masculine people share publicly to document their transition.

Does the science back this up?

Yes, voice deepening is one of the most consistently documented and irreversible effects of testosterone therapy in transmasculine individuals, and the timeline shown here is broadly consistent with published research.

Ziegler et al. (2018, Journal of Voice) found that fundamental frequency, the acoustic measure of pitch, drops significantly within the first three to six months of testosterone therapy, with continued change through the first year. A 2019 systematic review by Liao et al. in Transgender Health confirmed that vocal changes are among the earliest and most reliable masculinizing effects, typically beginning within weeks of starting therapy and stabilizing somewhere between six months and two years, depending on the individual.

The progression captured in this video, from a higher-pitched voice at day one to a noticeably deeper voice at two years, is exactly what the literature predicts. The five-month mark showing already-audible change is also consistent with documented timelines. Nothing here contradicts the evidence.

What did they get wrong (or right)?

They got the core thing right: testosterone does change the voice in transmasculine people, and the changes do follow roughly this timeline. Credit where it is due.

What they did not address, which is worth flagging, is that voice change is not linear, uniform, or guaranteed to produce any specific outcome. Rider et al. (2019, Journal of Endocrinological Investigation) noted that vocal outcomes vary substantially based on age at initiation, baseline hormonal profile, dose, and route of administration. Some people experience cracking, instability, or a longer plateau period. Showing a clean progression in a short video can create the impression that this is what everyone gets, on this schedule. It is not.

There is also no mention of voice therapy, which the American Speech-Language-Hearing Association notes can complement hormonal changes for transmasculine individuals who want to optimize resonance and articulation. Testosterone changes pitch, but trained vocal habits matter too.

None of this makes the video wrong. It just makes it incomplete, which is a reasonable limitation for a personal TikTok milestone post.

What should you actually know?

If you are considering testosterone therapy and vocal change is part of what you are hoping for, here is what the research actually supports.

• Voice deepening is one of the few effects of testosterone that is considered permanent and irreversible, even if therapy is stopped (Seal, 2017, Clinical Endocrinology).
• Changes typically begin within weeks to months and continue for one to two years, but the endpoint varies widely by individual.
• Age matters: people who start testosterone after the larynx has fully developed may see smaller pitch shifts than those who start younger (Van Borsel et al., 2008, Journal of Voice).
• Route and dose of testosterone can influence the speed and degree of change, but no specific protocol can guarantee a particular vocal result.
• Working with a speech-language pathologist who has experience with trans patients can help with resonance, projection, and communication beyond just pitch.

This video is a personal milestone post, not a medical guide. Treat it as one data point from one person's experience, not a roadmap for your own.