A new study in JAMA Network Open is giving us more information about how gender-affirming hormone therapy (GAHT) might affect the heart’s electrical system. For transgender people who take hormones, this study is an important reminder that affirming care and overall health go hand in hand.
What the Study Found
Researchers in France followed transgender adults who were taking hormones between January 2021 and January 2023. They looked at the electrical signals in the heart, which can be measured with an electrocardiogram (ECG or EKG).
One of the main things they measured was the QT interval, which is the tiny fraction of a second it takes for the heart’s muscle cells to reset after each beat. If the QT interval is too long, it can raise the risk of dangerous heart rhythms. If it is too short, it can also signal possible problems.
Here is what they discovered:
- Trans men (people assigned female at birth who are taking testosterone) tended to have a slightly shorter QT interval and stronger “T waves” (another part of the ECG signal that shows how the heart resets between beats).
- Trans women (people assigned male at birth who are taking estrogen along with medications to lower testosterone) showed the opposite trend, with slightly longer QT intervals.
These changes match what is already known about the natural differences between men’s and women’s heart rhythms. The study confirms that hormone therapy can shift a person’s heart patterns in those same directions.
Why This Matters
The QT interval becomes more important if someone is also taking other medicines that can make it longer. Too much QT lengthening can lead to a rare but dangerous type of irregular heartbeat called torsades de pointes.
This does not mean that GAHT is unsafe. It means that doctors and patients should be aware of these small changes so they can keep an eye on heart health. For most people, the benefits of gender-affirming hormones far outweigh the risks, but regular check-ins are always a good idea.
What Patients Can Do
- If you are starting GAHT, consider asking your doctor for a baseline ECG and occasional follow-ups.
- Tell your doctor about all the medicines and supplements you are taking so they can watch for any possible QT-related issues.
- Remember that checking your heart health is not about questioning your transition. It is about making sure your care is as safe as it is affirming.
The Bottom Line
Studies like this are valuable because they include transgender people in medical research instead of leaving us out. The more we understand about how hormones affect every part of the body, the better doctors can personalize care.
As gender-affirming care becomes more accessible, having solid science that reflects our lived realities is one of the best ways to ensure health and safety while still celebrating the life-changing power of transition.
