What did @siem_maasdijk actually say?
Honestly? Not much that's medically analyzable. The transcript is largely incoherent, likely the result of auto-captioning a video where the creator's voice is mid-transition and speech recognition failed badly. What we can work with is the caption, where Seymour describes medically transitioning, references testosterone use via the #testosterone and #ftm hashtags, and frames physical changes as becoming "more like the person I was when I was younger." The voice update framing, via #voiceupdate, signals that vocal deepening from testosterone is the main subject.
So let's be clear: we're fact-checking the claims embedded in the caption and video context, not a garbled auto-caption that misread a transitioning voice as repeated phrases. That's actually a real phenomenon worth noting in itself, and we'll get to it.
Does the science back this up?
Testosterone does cause voice deepening in transgender men, and the evidence is solid. This is one of the better-documented effects of gender-affirming testosterone therapy. Multiple studies confirm that fundamental frequency (the acoustic measure of pitch) drops significantly within the first year of testosterone use.
Ziegler et al. (2018, Journal of Voice) found that mean speaking fundamental frequency in transgender men dropped from approximately 196 Hz to 117 Hz after one year of testosterone therapy, overlapping substantially with cisgender male ranges. Damrose (2009, Journal of Laryngology and Otology) documented laryngeal growth and vocal fold elongation as the mechanism, which is the same process that occurs in adolescent males during puberty.
The creator's description of a "bumpy ride" is also accurate. Voice changes during testosterone therapy are not linear. They mirror adolescent voice break, including cracking, inconsistency, and periods where the voice feels unpredictable. That's not a side effect to be alarmed by; it's the biological process working as expected.
What did they get wrong (or right)?
Seymour gets credit for framing this honestly. Describing transition as "healing" and "self discovery" while acknowledging it's been "bumpy" is a grounded take, not an oversell. There are no claims here that testosterone is a cure, no dosage recommendations, no dangerous stacks being promoted. That alone puts this video well above a lot of health content on TikTok.
The framing of "becoming more like the person I was when I was younger" is interesting. It's not a medical claim, but it does loosely map to research. Van der Miesen et al. (2018, Clinical Psychology Review) found that gender-affirming care is associated with reduced psychological distress and improved quality of life, and many transgender individuals report a sense of authenticity rather than change post-transition. So while it's a personal narrative, it's one the data broadly supports.
What's missing is any acknowledgment that testosterone therapy carries real clinical considerations: cardiovascular risk monitoring, hematocrit elevation, fertility effects. That's not misinformation by omission, but it's worth flagging for anyone watching and considering starting therapy.
What should you actually know?
If you're considering testosterone therapy for gender transition, this is what the clinical picture actually looks like. Voice deepening typically begins within 3 to 6 months of starting therapy and continues for up to two years. It is considered an irreversible change, meaning it does not reverse if testosterone is discontinued.
Speech-language pathology can complement hormone therapy for voice training, particularly for resonance and speech patterns that testosterone alone does not change. Coleman et al. (2022, International Journal of Transgender Health) recommend a multidisciplinary approach that includes voice therapy alongside medical transition.
On the auto-caption failure: this is a documented problem. Voice recognition systems are largely trained on cisgender male and female voices, and transitioning voices, which may sit outside typical frequency ranges and have increased breathiness or cracking, are poorly recognized. A 2023 study in PLOS ONE by Markl et al. found that automatic speech recognition error rates were significantly higher for transgender speakers than cisgender ones. That's a tech equity issue, not a health one, but it matters when health information is being shared via video.
Finally, testosterone for gender-affirming care is a distinct clinical protocol from TRT for hypogonadism, even though both involve testosterone. Dosing, goals, monitoring, and informed consent processes differ. If you're exploring either path, the conversation starts with a clinician, not a TikTok comment section.