Transgender women who have undergone hormone therapy show comparable physical fitness to cisgender women, according to the most comprehensive analysis of its kind to date.
The review, published Tuesday (Feb. 3) in the British Journal of Sports Medicine, looked at 52 published studies that assessed the body composition, muscular strength and aerobic capacity of nearly 6,500 individuals, including about 2,900 transgender women and 2,300 transgender men.
“Sport is multifactorial,” senior study author Bruno Gualano, an associate professor at the University of São Paulo’s Center of Lifestyle Medicine, told Live Science in an email. “Training quality, access to facilities, psychological stress and exposure to discrimination all influence performance, and these factors are rarely captured in physiological studies.”
Systematic analysis
The analysis was motivated by recent efforts unfolding around the world to ban transgender people from athletic competitions.
“We’ve seen increasingly restrictive rules on transgender participation in sport, often justified by claims of large and unavoidable physical advantages,” Gualano said.
While circulating testosterone levels seem to increase muscle mass, strength and aerobic capacity, these bans, typically aimed at transgender women and girls, often argue that even past exposure to testosterone during puberty gives individuals a permanent and inherent physical advantage over cisgender women.
To see if that was the case, the researchers pooled data from many studies that employed different approaches and measures to compare physical fitness in transgender and cisgender people. The study participants ranged from 14 to 41 years old, and most were adults.
Among transgender women, hormone therapies included different forms of estrogen and antiandrogens, which suppress the effects of testosterone, while transgender men used various forms of testosterone. Most studies followed participants for about one to three years of therapy.
When normalized for height, “transgender women, after gender-affirming hormone therapy, do not show greater strength or aerobic capacity than cisgender women,” Gualano said. That included both upper and lower-body strength.
Transgender women also had comparable fat mass to that of cisgender women.
They have slightly higher lean mass, he noted, but that doesn’t translate into greater strength or maximal oxygen consumption. Studies rarely look at metrics of specific athletic performance, so the team could not assess that, Gualano added.
Most of the study participants included in the analysis were not competitive athletes, so “we should be cautious about extrapolating directly to elite sport,” Gualano noted. But that said, “if there were large, intrinsic physical advantages, we would expect to observe them even in non-athletic populations, and we do not.”
“What’s new here is the consistency of these findings across many datasets,” Ada Cheung, an endocrinologist and head of the Trans Health Research Group at the University of Melbourne, who was not involved in the study, told Live Science in an email. The results challenge the notion that trans women have intrinsic athletic advantages, she added.
Phoebe Toups Dugas, an associate professor of human-centered computing in the Exertion Games Lab at Monash University in Australia who was not involved in the study, agreed.
“Counter to narratives being used to push transgender athletes out of sport, there’s no evidence that transgender women have any kind of advantage,” she told Live Science in an email. “There’s no reason to ban us from playing.”
Olympic competition
While the U.S. Olympic Committee has banned transgender women from competing in women’s events to align with an executive order from President Donald Trump, the International Olympic Committee (IOC) has not yet done so. But recent reporting suggests that might change, as the IOC has said it will issue new rules this year. The IOC medical and scientific director has reportedly stated that, even after hormone therapy, transgender women who have gone through male puberty retain physical advantages over cisgender women. She has said the new rules also may apply to cisgender women with “male” characteristics, such as Y chromosomes or “male levels” of testosterone.
The results of the recent meta-analysis do not support those rules, Gualano said. While the new analysis can’t tell us anything about the fitness of cisgender women with relatively high testosterone, other datasets suggest that “performance is not determined by testosterone alone,” he added.
“A major gap in the literature is our limited understanding of how hormonal effects interact with long-term training and social context, particularly in women and gender diverse populations,” Gualano said. “Another gap lies in the assumption that testosterone thresholds neatly separate ‘fair’ from ‘unfair’ competition, an idea that is far less scientifically robust than often assumed.”
For now, the previous regulations are in place for the 2026 Winter Olympics, which kick off Feb. 6 in Milan. Elis Lundholm of Sweden will compete in mogul skiing as the Winter Games’ first openly transgender athlete. As this discussion unfolds, it’s important to note that few studies track transgender athletes in high-stakes competitions, in part because there are very few competing.
Given a lack of data on elite sports, an analysis like Gualano’s can be very informative, Toups Dugas said.
“These findings are of tremendous value to the IOC,” she said. “There is a big opportunity here for the IOC to make the Olympics more diverse and really support athletes.”
Youth sports
Most athletes, of course, aren’t competing in the Olympics. Instead, many are children playing youth sports. At least 29 U.S. states currently ban transgender youth from competing on teams aligned with their gender identity, and although some of these bans have been legally challenged, they are expected to be upheld by the U.S. Supreme Court in 2026.
Though the new meta-analysis included some data from adolescents, it was not enough to make robust conclusions about kids’ body composition, Toups Dugas said. “But I don’t think it needs to for us to make sensible choices.”
Cheung agreed. “There is no evidence here to justify categorical bans on trans youth in sport.”
This article is for informational purposes only and is not meant to offer medical advice.
Sieczkowska, S. M., Mazzolani, B. C., Coimbra, D. R., Longobardi, I., Casale, A. R., Da Hora, J. D. F. V. M. P., Roschel, H., & Gualano, B. (2026). Body composition and physical fitness in transgender versus cisgender individuals: a systematic review with meta-analysis. British Journal of Sports Medicine.
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