A multicenter longitudinal study presented in early 2026 analyzes the structural brain changes during the first six months of gender-affirming hormone therapy in a sample of 43 transgender people. The work is available as a preprint and is undergoing peer review.
Study design
The participants underwent two magnetic resonance imaging scans: one at baseline and another at six months of treatment. Changes in the volume and morphology of brain regions sensitive to sex hormones, such as the amygdala, the hippocampus and the cerebral cortex, were assessed.
Preliminary observations
The preliminary results point to structural modifications that vary according to the treatment (estrogens with or without antiandrogens, and testosterone), although the authors insist that these are initial findings that must be confirmed after scientific review and with larger samples.
This type of longitudinal study is essential to understand how hormones influence the brain of transgender people and to separate the effects of treatment from the characteristics preceding therapy.
Bibliographic reference: Hüpen P. et al. Longitudinal effects of gender-affirming hormone therapy on brain structure. Preprint, SSRN, January 2026. DOI: 10.2139/ssrn.6139319.
Publication consultation: Preprint on SSRN
