How Does Gender-Affirming Hormone Therapy Change the Body of Trans People?
A research team at the University of Leipzig is tackling this question in a new study. The second phase of the so-called “Hormones and Health” study is planned to begin in early 2027 and run for two years, the university announced during Transgender Awareness Week, observed from November 13 to 19.
“We’re interested in two big questions: What health effects does hormone therapy have for transgender people? And what can we learn in general about how estrogen and testosterone work in the human body?” said study director Haiko Schlögl.
Participants will be evaluated before starting hormone therapy and then after three, six, twelve, and twenty-four months. This approach makes it possible to track changes within the same person over time. The team aims to determine how muscle and fat composition, energy expenditure, and blood vessels change. In collaboration with the Max Planck Institute for Cognitive and Neuroscience, MRI will be used to examine whether certain brain regions undergo changes.
Trans Women Perceive Temperature More Acutely
In the first phase of the study, around 40 transgender individuals participated, evenly split between trans women and trans men. An initial result published this year in the journal Communications Medicine found that among trans women, treatment with estrogen and a testosterone blocker increased skin sensitivity to warmth and cold—roughly to the same extent as the differences observed between cis women and cis men.
“Our results are the first hints that under gender-affirming hormone therapy the skin’s temperature-sensing system may also adapt to the new hormonal gender,” Schlögl said. “The exact mechanisms still need to be explored.”
More Knowledge for Better Support
There is still too little known about potential health effects of hormone therapy, especially for the cardiovascular system and blood coagulation, Schlögl explained. “Only when we understand possible risks more precisely can we educate people and study how to reduce them.”
The physician also sees a need for more clinics that can support transgender people during hormone therapy. A study from University Medical Center Hamburg-Eppendorf this year found a lack of specialized services and experienced clinicians in parts of Northern Germany, as well as sometimes long travel distances to obtain care.
For the new study, the Leipzig team is still seeking cisgender women and cisgender men as comparison participants.
