New Review Finds No Clear Physical Advantage for Trans Women in Sports
A major review found no clear strength or aerobic fitness advantage for trans women after hormone therapy, challenging one of the claims used to restrict them from sports.
Trans women have been treated as if their bodies are evidence against them.
In sports, that treatment has often arrived through a simple claim: that transgender women retain a clear physical advantage and therefore threaten women’s competition. A major review of medical and sports-science evidence now cuts into that claim.
The paper, published in the British Journal of Sports Medicine as a systematic review and meta-analysis, was authored by a research team in Brazil that included Bruno Gualano, a physician and researcher at the University of São Paulo. It reviewed studies on body composition and physical fitness in transgender people receiving gender-affirming hormone therapy.
Across 52 studies and thousands of participants, researchers found no clear advantage for transgender women in the strength and aerobic fitness measures most often used to discuss sports performance after hormone therapy. The review did report higher lean mass in transgender women, but the central point is that this did not translate into a clear advantage in the performance measures examined.
Researchers found no clear advantage in upper-body strength, lower-body strength, or aerobic fitness between transgender women and cisgender women after hormone therapy.
That is the center of the finding.
The finding is not about flattening trans women into another measurement. It is about refusing to let one measurement become a weapon.
That distinction matters because trans women’s bodies are often flattened into one public assumption. Muscle mass gets treated as destiny. Hormone therapy gets treated as irrelevant. Transness itself becomes suspicion.
The review analyzed data from 6,099 people overall, including 2,566 transgender women, 2,646 transgender men, 442 cisgender women, and 445 cisgender men. Forty-two studies were included in the meta-analysis.
For transgender women, the contrast was direct. The review found higher absolute lean mass than cisgender women, but similar relative lean mass. It found no significant differences in upper-body strength, lower-body strength, or maximum oxygen consumption, a standard measure of aerobic fitness.
In plain terms, body composition and athletic performance are not the same thing.
That is not a technical footnote. It is the difference between measuring a body and making a claim about what that body can do.
The review also looked at how gender-affirming hormone therapy changed the body over time. In transgender women, one year of hormone therapy was associated with increased fat mass, reduced lean mass, and lower upper-body strength. Over one to three years, the pattern continued in the same direction, though not every measure could be tracked across every time span.
Gender-affirming hormone therapy changes the body. It changes muscle, fat distribution, strength measures, and the physical conditions under which people train and participate.
Yet trans women are often discussed as if none of that happens.
The review’s findings make that shortcut harder to defend. Strength and aerobic fitness are performance outcomes. Lean mass is one part of body composition. Treating one as proof of the other is not what this review found.
Gualano said the findings do not support the idea that transgender women would dominate women’s competitions after hormone therapy.
For trans women and trans girls, the stakes are not abstract.
Sports are school life. They are movement, friendship, confidence, teamwork, health, routine, and community. For young people, a team can become one of the first places where belonging is practiced in public.
When trans girls are pushed away from sports, the harm reaches beyond competition. It tells them their bodies are unwelcome before they have even stepped onto the field. It tells them participation is conditional. It turns ordinary movement into something they are expected to justify.
That is not a small harm.
This review does not make trans women’s dignity dependent on data. That dignity already exists. Trans women and trans girls already deserve movement, safety, team life, school life, and public belonging.
What the study does is clarify a claim that has been used to mark trans women as physically unfair by default. Across the reviewed performance measures, that claim did not carry the certainty so often attached to it.
The evidence base is still developing. The review included studies with different designs, many studies were short in duration, and data on elite athletes remains limited. Those limits matter. They do not erase the central finding.
In the reviewed data, transgender women receiving hormone therapy did not show a clear advantage over cisgender women in upper-body strength, lower-body strength, or aerobic fitness.
That finding belongs in the public record because trans women’s bodies have been measured, politicized, doubted, and used to justify exclusion.
The review found higher lean mass. It did not find clear advantage in the strength and aerobic fitness measures studied after hormone therapy.
That difference matters because evidence should not be distorted to make fear look stronger than it is.
Trans women should not be excluded from sports by assumption. Trans girls should not have their belonging treated as something that must be solved before they are allowed to play.
They are people with bodies, lives, teams, schools, families, communities, and a right to movement without being treated as danger first.
The study does not grant trans women dignity.
They already have it.
What it does show is that one of the claims used to restrict trans women from sports is weaker than the public has been told.
Trans women deserve more than public suspicion, institutional targeting, and policies built around fear.
This reporting matters because trans women and trans girls are being pushed out of movement, sports, school life, and public belonging through claims about their bodies that the evidence does not clearly support. Trans United documents that harm from the center of trans life — where dignity is not theoretical, and belonging should not have to be earned by disproving fear.
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So how long would a trans woman have to be taking hormone therapy before being allowed to compete? In general, males have more fast-twitch muscle fibers than females, which is what gives them greater strength. How does hormone therapy change the fiber ratio? Does it change the fiber ratio or is there something else at play here? I am a histology technician by training and profession and used to do muscle histochemistries in the clinical laboratory. I would be interested in correlating the change in muscle fiber composition during the process - wow, this has opened up a lot of questions.
I'm a high functioning athlete, have been my entire life. I knew I was going to lose a lot of athletic capacity once my testosterone was reduced. I had no idea it would be so dramatic. I've read many articles and scientific studies on this. This information combined with my own experience very definitely points to a lack of retained advantage after GAHT. And since I've tracked my performance from before I transitioned, I have the receipts.