What did @mx.gialu actually say?
The creator pushed back on a common assumption: that their physique is simply a product of testosterone. Their actual argument was more nuanced. They said testosterone "makes it easier" to build muscle, but credited their results to "working out almost every single day" and eating enough protein. They also made a specific pharmacological claim: that their testosterone levels are equivalent to "the average cis man," which is worth examining closely.
They also invoked a reasonable logical test: if testosterone alone built muscle, every man would look the same. That is not a perfect argument scientifically, but the underlying point, that training and nutrition do the heavy lifting, is defensible.
Does the science back this up?
Mostly, yes. The evidence is fairly clear that testosterone does support muscle protein synthesis, but the effect is not automatic. It requires resistance training to manifest meaningfully.
A landmark study by Bhasin et al. (1996, NEJM) randomized men to testosterone or placebo, with or without exercise. The testosterone-plus-exercise group gained the most muscle, but testosterone alone did produce some gains even without training. That is a wrinkle the creator glosses over: testosterone is not entirely passive. It does have an independent anabolic effect, even at rest, though the magnitude is modest compared to training.
For transmasculine people on gender-affirming testosterone therapy, studies like Klaver et al. (2018, Journal of Clinical Endocrinology and Metabolism) found increases in lean body mass over 12 months. That is a real effect. The creator is right that you still need to train, but slightly wrong that testosterone is purely facilitative.
What did they get wrong (or right)?
They got the core message right: training and nutrition are the primary drivers of visible muscle development. No serious sports scientist would argue otherwise. The creator deserves credit for pushing back on a reductive narrative.
Where they overstep is the claim that being on testosterone puts them on equal footing with "any other cis man." That is not quite accurate. Testosterone levels in transmasculine people on hormone therapy can vary widely depending on the formulation, dose, injection timing, and individual metabolism. A trough level on injection day is not the same physiological environment as a stable endogenous level. Research by Deutsch et al. (2015, LGBT Health) noted significant variability in testosterone levels among trans men on different protocols.
The "every cis man would look the same" argument is also a logical shortcut. Testosterone receptor sensitivity, genetics, and androgen receptor density vary enormously between individuals. Two people with identical testosterone levels can have very different anabolic responses. The creator is right that muscles require work, but the mechanism they use to prove it is oversimplified.
What should you actually know?
If you are on testosterone therapy and wondering why your body composition is or is not changing, the research points to a few consistent findings. Resistance training is the primary lever. Testosterone creates a more anabolic hormonal environment, but that environment is not automatically converted into muscle without mechanical stimulus.
Protein intake matters too. The International Society of Sports Nutrition recommends 1.6 to 2.2 grams of protein per kilogram of body weight per day for individuals seeking muscle hypertrophy (Morton et al., 2018, British Journal of Sports Medicine). Testosterone does not replace that requirement.
For transmasculine people specifically, the timeline for body composition changes on testosterone is longer than many expect. Lean mass increases tend to be meaningful by 12 months but continue evolving over years. Comparing your physique to someone who has been training for a decade and has been on testosterone for years is not an apples-to-apples situation, regardless of current hormone levels.
The creator's broader point, that trans men with muscular physiques earned those physiques through work, is accurate and worth saying plainly. Attributing someone's body entirely to their hormones, whether to dismiss their effort or to make a claim about competitive advantage, requires a lot more nuance than a single variable like testosterone level provides.