NIH-funded study: Puberty blockers enhance cardiorespiratory fitness in trans adolescents receiving testosterone
The United States National Institutes of Health (NIH) has systematically disinvested from research on the health of trans people since the Trump-Vance administration assumed office, with the ultimate goal of focusing on transition-related “regret.” A recent (October 2024) study provides insight into the type of NIH-funded research that will be notoriously absent in years to come, especially since its counters right-wing misinformation about trans adolescents.
An NIH-funded study published in October 2024 provides insight into possible fitness benefits of puberty blockers (also known as GNRH agonists). A research team at the University of Colorado Anschutz Medical Campus was interested in testing the effect of the medicine in transmasc adolescents starting testosterone replacement therapy.
We already know that puberty blockers are safe and reversible, a far cry from the “chemical mutilation” that the Trump regime claims them to be. This study was interested in cardiorespiratory health as no previous research has focused on this facet of health in trans adolescents.
The study itself was “noninterventional,” meaning that the research team was not directing or altering the medical decisions made by the participants and their doctors. Rather, they simply measured indicators of cardiorespiratory health (including exertion on an exercise bike) at three time points: before starting testosterone, one month after starting T, and one year after starting T.
These measurements were taken across two cohorts: one cohort of 11 adolescents who had never received puberty blockers and another cohort of 8 adolescents who had been taking blockers for ~2 years prior to the study. These 8 individuals continued to take puberty blockers during the 1 year period of research.
Otherwise, the two cohorts were similar demographically (albeit largely white), between 14-15 years old. All the study participants and their guardians consented to both the study and the medical transition.
All participants showed increases in their respiratory exchange ratio (RER, a measure of aerobic fitness). Further, those receiving puberty blockers and testosterone saw additional fitness improvements. Namely, after 12 months they were leaner (measured by the percent of body mass that is fat-free), had greater endurance (measured by the amount of cycling time until they reached exhaustion), and greater strength exerted during the cycling test.
As the powerhouse of the cell, mitochondria are critical to providing the energy to power your muscles during exertion. So, the researchers hypothesized that the fitness differences they observed may be due to changes in mitochondrial functioning. To test this, they profiled the metabolites present in the participants’ blood and observed elevated metabolites associated with enhanced mitochondrial energy production.
Notably, the participants largely lived sedentary lifestyles and were not involved in organized athletics. So, these changes cannot be explained by additional training performed by the cohort on puberty blockers. Instead, these fitness improvements simply help to complete everyday tasks.
Ultimately, this is “the first study to evaluate differences in cardiorespiratory fitness among transgender adolescent males undergoing testosterone therapy, specifically those who did or did not receive [puberty blockers].” There is still a lot more to learn, but these data suggest that puberty blockers are beneficial for adolescent fitness and physiology when taken at the onset of testosterone replacement therapy.
It is critical for other studies to replicate these results and expand the research to investigate the effects of puberty blockers on the health of transfemme adolescents. However, these studies are expensive.
For years, the NIH funded basic health research in the United States. In fact, this study was made possible by two NIH grants awarded to the research team. Fortunately, they able to complete and publish their work before the 2024 election. But, the NIH under the Trump-Vance administration is decimating the American biomedical research landscape by leveraging grants to control universities and wantonly terminating grants on now-verboten topics, including trans health.
Without NIH funding for studies like this, conducting research on trans health will be nearly impossible in the United States. (Private funders could step in to fill this gap, but I am not optimistic at this possibility.)
Of course, this is by design. The lackeys of the Trump regime don’t want us to have access to information on the potential benefits of puberty blockers and other transition-related care. Instead, they want trans people gone — one way or another. Why else would they be investigating hormone pharmaceutical manufacturers and defunding suicide hotlines for queer youth?1
And yet, the truth remains. As demonstrated by this NIH-funded research, the right-wing narrative that puberty blockers destroy the lives of trans youth is a lie. Instead, puberty blockers enrich the health of trans adolescents — not only with fitness benefits but also with improvements in mental health.
Trans adolescents deserve access to these medicines.
from the archive
If you or a loved one is struggling with self-harm or suicidal ideation, please contact hotlines through the Trevor Project or Trans Lifeline. I no longer recommend that queer folx call the National Suicide and Crisis Lifeline (988).
Great article as usual ev!