Overview
- Pooling 52 studies with 6,485 participants, researchers reported that one to three years after hormone therapy, transgender women’s measured strength and VO₂ max are comparable to cisgender women’s despite higher lean mass.
- Transgender men in the included studies showed lower fat, higher muscle, and greater strength after hormone therapy, with strength levels below cis men but above cis women where data allowed comparison.
- The authors describe substantial limits to the evidence base, including short follow-ups, heterogeneous designs, sparse adjustment for training history and nutrition, and little data on adolescents or puberty suppression.
- Scientists and campaign groups offered sharply different readings of the findings, with critics arguing the review overlooks training status and immutable skeletal traits and supporters saying it undercuts the case for blanket exclusions.
- Sporting authorities are weighing the study as they revisit eligibility rules, with recent UK federation bans cited in debate and the IOC’s potential tighter policies under discussion, while experts call for long-term, sport-specific research on elite athletes.