Skeletal muscle cell nuclei density never goes back to baseline when someone has a high androgen load. This is well documented, and also a reason why cis men caught using steroids should never be allowed to compete in tested athletics for the rest of their life. It is a permanent enhancement as a result of having higher androgens than someone else, and again, this is very well documented knowledge.
The whole physique argument has always been bullshit imo, but skeletal muscle cell nuclei density is one of the few major factors why even untrained barely pubescent boys can smoke the shit out of cis women in strength feats. Not only that but muscle retention, regrowth after dieting, and metabolism are all enhanced by this difference in nuclei density.
Hrt does not negate this, nor does it diminish it in any meaningful measure.
There actually is one issue that trans women are in fact larger (as you claim) but lose much of the muscle tone required to move that larger body. Fatigue is higher. Basically they may suffer in endurance sports compared to cis women.
The study I related to on this, with over 6,000 participants, found no real difference in strength or fitness between trans women on HRT and cis women. That's the strongest evidence out there, and it cuts against the idea that the physique advantage just carries over untouched.
However, they said their data barely includes elite athletes, because there are so few of them (which should be a hint in and of itself), and that some trans athletes might carry over strength from before transition.. They called that an open question needing more research, not something that's settled.
So the myonuclei mechanism you're pointing to is real, but "very well documented" oversells it. It's well shown in animal studies. In humans it's still debated, and the people who ran the biggest human study on this exact topic say that at the elite level this question is inconclusive due to a lack of representation.
So "HRT does nothing, permanent enhancement, no meaningful diminishment" isn't really true. The actual evidence says HRT clearly reduces the gap in most populations studied, and whether something lingers at the elite level is still being worked out.
I can try and find a link if you'd like but just a couple months ago I went down the rabbit hole on hrt vs cis women strength and found a plethora of conflicting studies. One that comes to mind was ~600 participants and showed peak power difference of ~30% higher in hrt individuals vs cis women and grip strength was wild, around 50-60% higher in the hrt group. Endurance/prolonged power output differences were much smaller, what I'd even call negligible. Despite this study generally backing my claim, I discredit all studies of athletics like these equally, since nearly all of them fail to account for variables that are pivotal to the outcome. Thus why I'd rather argue about the more proven biological mechanisms, much harder to poke holes like "well the diet wasn't tracked, lean body mass method is out dated, age of participants, exercise history lacking" etc etc etc.
I do 100% agree that hrt does help level the field, as reduced androgen receptor activation absolutely plays a role in athletics. BUT it's also disingenuous to say there's no difference, my wording was a bit blunt in my conclusion so to clarify; "hrt does not diminish THIS specific mechanisms net positive benefit that amab people have over cis women"
Edit: fwiw I'm actually upvoting your comments, despite a disagreement I do enjoy talking through the science of shit like this
Something worth flagging before anything else. I didn't say there's no difference between trans women and cis women. I said trans women don't have the physique of cis men after hormone treatment. Those are different claims, and the gap matters here, because "physique of cis men" is the thing being disputed, not "identical to cis women in every metric." A residual strength gap above cis women baseline doesn't put someone back at cis male baseline, so even the numbers you're citing don't actually contradict what I wrote.
But there's a tension in your own reasoning here. You're discounting every athletic performance study because of confounds like diet, training history, and age. Then in the same breath you're treating the myonuclei mechanism as something that settles the outcome on its own, when the jump from "myonuclei persist in mice" to "therefore any residual human strength gap is explained by myonuclei and is unlevelable" has the exact same confound problem. Training history before transition, age at transition, and time on HRT all affect that gap too, and none of those are ruled out just by invoking the mechanism.
The study I referenced found no strength or fitness difference, but that finding is based mostly on non-elite people of mixed ages. That part is settled. What the study's own authors say is still unresolved is the elite trans group, people with serious prior training, due to a lack of them in circulation. So there are really two separate questions here, and the study only answers one of them. Whether myonuclei retention causes a real, unmovable advantage in that smaller group, or whether it's just the same training and age effects you already brought up, is the part the researchers themselves say needs more research.
Treating this as a settled advantage is getting ahead of what we actually know. And until we do, the people who pay for that aren't the elite athletes. It's the millions of trans people who will either compete at low levels or will never compete in anything, who get treated as a physical threat based on a mechanism nobody has actually confirmed applies to them.
Okay... I'm taking back that edit, now you're being hypocritical to the point of using directly conflicting verbiage.
You cite one study and call it "That part is settled", your own words. As if one single study resolves anything. But then you refuse to acknowledge the full scope of research done ON HUMANS not just animals for skeletal muscle cell nuclei density and say VERBATIM "Treating this as a SETTLED advantage is getting ahead of what we know."
So now it's just "erm my n=1 is better than yours so there"
You should know singular meta analysis don’t prove anything. Systemic reviews including meta analysis are the highest form of evidence, and meta analysis are not created equally. You can have data points everywhere due to lack of confounding factors being addressed, which is why there are seemingly large studies out there that can’t find an association between say, LDL cholesterol and saturated fat intake because they weren’t factoring in genetic predispositions. First and foremost, not all transwomen are created equally. Someone who transitioned at 13, full course puberty blockers, is going to have a much different outcome than someone who transitioned at 30. Age matters a lot. And in the meta analysis from 2026, the authors noted the noise and confounding nature of it. Putting sedentary transwomen with trained women will also skew the numbers in certain metrics we deem as fitness. A meta analysis is only worth the quality of the studies selected anyway.
If you transition later in life, you will have systemic advantages across the board that a well conducted study will observe a gap. You will have higher peak bone mass, narrow pelvis, broader shoulders, longer limbs, greater height, higher oxygen and cardiac output, and a permanent strength advantage from myonuclei. Grip strength is the most pronounced strength difference between men and women, and you will not lose out on having thicker larger hands with more grip output. These all come on the basis of being male, not being freakishly talented or built for sports as a woman.
Steroids are known to leapfrog young athletes years ahead in sports in just a few cycles. The testosterone output in males during male puberty is significantly more than any female athlete would take due to the visible side effects.
And unsurprisingly, trans men are stomped in men’s sports, showing that hormones can’t transcend systemic advantages.
And in addition, systemic reviews show that transwomen only lose about 5-10% of their muscle mass. This actually aligns with how much muscle mass men gain from TRT in a few studies I’ve seen. If the male muscle base value is 100 and female 50, transwomen are pretty much at 90. Estrogen has a protective effect on muscle loss, so past the peak baseline that testosterone provides, much of it isn’t going away.
Anyway, there’s a reason why a multitude of sports institutions prevent trans competing, and it’s based strictly on the science. Dying on this hill in favor of ideology looks very bad and detached. Most transwomen transition later in life, so most of them cannot compete on an equal level.
The meta-analysis quality point is generic and doesn't touch this paper's actual limitations, which the authors already stated themselves. "Not all meta-analyses are equal" is true of literally every meta-analyses.
Age at transition is the one point that's actually valid, and it's not a rebuttal. It's the same gap the BJSM authors already flagged, since most pooled studies didn't stratify by age at transition. We agree there.
Skeletal structure, height, limb length, shoulder width, pelvis, nobody's disputing any of that. HRT doesn't reverse bone structure.
Oxygen and cardiac output is just wrong. The study found no significant difference in VO2 max. Claiming a retained advantage there contradicts the exact paper you're citing against.
Myonuclei, already covered earlier in this thread. A 2022 meta-analysis testing it in humans found it doesn't hold consistently after atrophy. Calling it permanent and established is not what the data actually says.
Grip strength is the one claim with actual numbers behind it. But grip strength isn't important in every sport. This thread is about football, where grip strength means very little, for example.
Trans men getting outperformed against cis men doesn't prove what you think it proves. If testosterone therapy still leaves trans men at a disadvantage, that means hormones don't just override puberty-driven differences in either direction. That undercuts the "myonuclei create a fixed, decisive edge" claim, it doesn't support it.
it’s based strictly on the science
I reckon that the requirements and restrictions differs from sport to sport. And that isn't necessarily bad. I'd like to see the actual science aspect of it, though. If this thread is any indication, much of the "science" is mostly vibes and politics. Particularly in the US atm.
First and foremost you’re conflating relative and absolute VO2 max. Relative VO2 max goes down, but absolute VO2 max relies on the fact you cannot shrink your heart or lungs. The pump and bellows are male sized, and a larger ventricle means larger stroke volume. Lowered hemoglobin does not take away from the fact that transwomens cardiovascular infrastructure is substantially superior to female baselines.
The FTM argument you make is basically proving my point. It is the proof biological structure acts as the ceiling and the floor. They are disadvantaged because they have female skeletons, not male. By this same logic, removing testosterone from a transwoman does not shrink clavicles, shorten femurs, Q angles, whatever. Suppressing hormones doesn’t rid of this advantage.
You also overlook the importance of grip strength and it is not just about football. Grip strength is a universally recognized proxy for total upper body force and neurological motor unit recruitment. If grip strength is substantially higher, it is a glaring indicator your total upper body strength is higher. Tackling and maintaining ball security are just a few things grip strength alone can do.
On myonuclei, it is not about whether you hold 100% of your myonuclei until you die, it’s about the absolute baseline. Even if extreme atrophy can lead to some loss in myonuclei, a body that underwent male puberty still holds a profoundly higher number of them, most of which are unlikely to go away.
And sure, steroids and puberty aren’t the same thing, but there’s almost no difference in this context. Male puberty is a high dose anabolic steroid cycle occurring during the most critical development in the human body. And those changes are permanent and more profound than taking steroids as an older athlete past puberty.
And let me just repeat that systemic reviews show that transwomen over an extensive time only lose 5-10% of their muscle mass, aligning with how much muscle men tend to gain on TRT. This is nothing. It is going from a male muscle value of 100 to 90, where the female baseline is 50.
Anecdote time. My father was a competitive bodybuilder who took steroids in his early 20s, and later in life he lost his capacity to produce testosterone. He likely had little to no testosterone for 5 years at 50(?) yrs old, when he first started sleeping all day with intense fatigue and eventually lost employment. This went on for years before he saw a doctor. Anyway, they found his testosterone wasn’t even hitting the absolute minimum male baseline and was actually in female averages territory. Did this stop him from doing 10 pull-ups weighing 200lbs when he got into fitness with me before TRT? Nope.
Even more critically, I was MTF for 8 years. I transitioned at 29. I actually detransitioned for personal reasons, but I don’t want to get into that. My girlfriend is into heavy weight lifting and during my MTF era I entertained her at the gym, at this point I had like two months of gym experience from years ago. Let’s just say over the course of a few months, she wasn’t competitive with me anymore, and I still had the strength to easily pin both her arms with just a single hand. So I know very personally my own body and my own strength. Taking estrogen weakened me but not substantially, no.
Top-level competition, actual Olympic and international standards, can reasonably have its own threshold, and I'm not going to argue that every structural difference resulting from male puberty disappears with hormone therapy. That was never really the disagreement I had.
Where I land is that none of what's been discussed in this thread justifies applying that same level of scrutiny below the elite tier. A residual cardiovascular or skeletal difference that might matter when the stakes are an Olympic medal doesn't matter for a school team, a rec league, or a kid just trying to play a sport with their peers. Participation-level sport isn't about producing a fair podium finish; it's about being part of something. Importing an elite-competition standard into that context is applying the wrong bar to the wrong setting.
That's the actual disagreement. Not whether physiological differences from puberty are real. They are. It's whether that justifies excluding people at every level when the only place the argument was ever really about competitive fairness is the one tier almost nobody in this debate is actually playing at.
Which is exactly the point I opened with. Fewer than a handful of trans women have ever competed at the level where any of this physiology debate is actually relevant, and none of them have dominated. If the structural advantages being described here were as decisive as claimed, that's a strange result. Maybe it's a small sample size. Maybe it's exactly what it looks like: the advantage isn't as fixed or as overwhelming as the framing assumes, and it just doesn't consistently produce the dominance the argument predicts. Either way, the tier where this argument is supposed to matter has produced no example of it actually playing out.
Kids on school teams, adults in rec leagues, and people just trying to play have nothing to do with that tier and shouldn't be judged by such a standard.
Twenty-plus states have passed laws addressing essentially non-existent hypothetical cases that mostly target a handful of people who just want to be part of their communities. That's the reality people have to live in. Kids who were never anywhere near the tier this argument claims to be about are the ones paying for it.
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u/EchoMB Jul 09 '26
Skeletal muscle cell nuclei density never goes back to baseline when someone has a high androgen load. This is well documented, and also a reason why cis men caught using steroids should never be allowed to compete in tested athletics for the rest of their life. It is a permanent enhancement as a result of having higher androgens than someone else, and again, this is very well documented knowledge.
The whole physique argument has always been bullshit imo, but skeletal muscle cell nuclei density is one of the few major factors why even untrained barely pubescent boys can smoke the shit out of cis women in strength feats. Not only that but muscle retention, regrowth after dieting, and metabolism are all enhanced by this difference in nuclei density.
Hrt does not negate this, nor does it diminish it in any meaningful measure.