Muscle strength appeared to increase during masculinizing gender-affirming hormone therapy and decrease during feminizing gender-affirming hormone therapy, whereas physical activity was unchanged, though high risk of bias means more research is necessary.
Key Findings
Results
Masculinizing gender-affirming hormone therapy resulted in increased or unchanged muscle strength across included studies.
Four out of six studies reported increased muscle strength with masculinizing gender-affirming hormone therapy.
Two out of six studies reported unchanged muscle strength with masculinizing gender-affirming hormone therapy.
Muscle strength changes mainly occurred during the first year after initiating gender-affirming hormone therapy.
Age at initiation had no impact on muscle strength changes.
Results
Feminizing gender-affirming hormone therapy resulted in decreased or unchanged muscle strength across included studies.
Three out of six studies reported decreased muscle strength with feminizing gender-affirming hormone therapy.
Three out of six studies reported unchanged muscle strength with feminizing gender-affirming hormone therapy.
Muscle strength changes mainly occurred during the first year after initiating gender-affirming hormone therapy.
Transmasculine persons had higher strength compared with cisgender women but lower strength than cisgender men.
Transfeminine persons had higher strength compared with cisgender women but lower strength than cisgender men.
Results
Physical activity levels were largely unchanged during gender-affirming hormone therapy in prospective studies.
Physical activity was unchanged during gender-affirming hormone therapy in five out of prospective studies.
Transfeminine persons were less physically active than cisgender men in five out of five prospective studies.
Methods
The systematic review included 15 studies with data on 1206 transgender persons.
722 transmasculine persons were included, with median age ranging from 23 to 37 years.
484 transfeminine persons were included, with median age ranging from 27 to 41 years.
Eight out of 15 studies used a prospective design and seven out of 15 were cross-sectional.
Handgrip strength was the most commonly assessed outcome, used in 12 out of 15 studies; lower body strength was assessed in four out of 15 studies; isometric elbow flexion/extension in one out of 15 studies.
Nørlund M, Christensen L, Andersen M, Kristensen T, Frystyk J, Mathiesen J, et al.. (2025). Muscle strength changes and physical activity during gender-affirming hormone therapy: A systematic review.. Andrology. https://doi.org/10.1111/andr.70058