A longitudinal study planned for 2027
Researchers in Leipzig are preparing a two-year study examining how gender-affirming hormone therapy affects energy use, body composition and blood-vessel function. The new cohort is expected to begin in early 2027 and builds on the first phase of the Hormones and Health study, according to Leipzig University information reported by Medical Xpress.
The project brings together researchers from the Helmholtz Institute for Metabolic, Obesity and Vascular Research, Leipzig University and the University of Leipzig Medical Center. Its stated aims are both clinically relevant and broader: to investigate health effects of hormone therapy for trans people, and to improve understanding of how estrogen and testosterone act in the human body.
Why following the same people matters
Participants will be examined before they begin hormone therapy and then at three, six, 12 and 24 months during treatment. That design allows researchers to track changes within the same person over time rather than relying only on comparisons between different groups of people.
Study leader Haiko Schlögl said the team is particularly interested in the ways sex hormones affect body composition, including relative amounts of muscle and fat, as well as energy expenditure and the vascular system. This kind of repeated assessment may help researchers distinguish treatment-associated changes from differences that would be harder to interpret in a one-time comparison of separate populations.
More detailed metabolic and vascular measurements
The next phase will add more precise methods to the study. A metabolic chamber will be used to measure energy expenditure. The team also plans tests designed to provide detailed information about blood-vessel function, testosterone's effects on blood flow and markers associated with harmful changes in blood vessels.
Those measurements place metabolism and vascular health at the center of the study rather than treating hormone concentrations alone as the endpoint. The researchers will examine serum testosterone and estradiol concentrations alongside physiological measures collected over the two-year period. The source material identifies these areas as key components of the planned research, not as findings already established by the new cohort.
Potential value for trans health and hormone science
Gender-affirming hormone therapy provides a research setting in which hormone levels change over time and can be studied alongside repeated health assessments. The researchers say the findings could have implications for the health of trans people while also helping explain how sex hormones influence metabolism and blood vessels in the wider population.
That dual purpose is central to the project. Its first question concerns the health effects of therapy for participants. Its second asks what carefully measured changes can reveal about the roles of estrogen and testosterone more generally. The study is therefore positioned as a prospective observational effort, not as a claim that it can answer every question about hormone therapy or predict outcomes for every individual.
Collaboration and research scope
The program is associated with the LeiCeM Cluster of Excellence, which studies human metabolism and the development of metabolic disease. The planned collaboration also includes the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, according to the source. Together, the participating institutions will expand the methods used in the first study phase.
Because the new cohort has not yet begun, its outcomes remain unknown. The significance lies in the study design and its planned measurement depth: baseline assessments followed by several time points, direct measurement of energy expenditure, and focused vascular testing. If completed as planned, the research could provide a more detailed picture of physiological changes during the first two years of gender-affirming hormone therapy.
What the study does and does not establish today
The announcement is a description of forthcoming research, rather than a report of new clinical results. Its value is in setting out a structured, longitudinal investigation into questions that are relevant to participants and to metabolic science. The researchers intend to study how changes in estrogen and testosterone relate to muscle, fat, energy expenditure, blood flow and vascular markers.
Results will be needed before drawing conclusions about the direction or size of those effects. Until then, the project represents an effort to generate more detailed evidence through repeated measurements over two years. For research on sex hormones, that paired focus on trans health and fundamental human physiology could make the upcoming cohort particularly informative.
This article is based on reporting by Medical Xpress. Read the original article.
Originally published on medicalxpress.com
