Estrogen use in trans-identified males is associated with a wide range of serious health risks—including blood clots, stroke, cancer, infertility, and cognitive decline.
A 2025 review1 summarizes wide-ranging risks tied to estrogen use in trans-identified males:
- 2.2× higher risk of blood clots (VTE)
- Up to 10× higher risk of stroke after 6 years on estrogen
- 1.8× higher all-cause mortality compared to other males
- 22.5–40.7× higher risk of breast cancer vs. male baseline
- 3× higher risk of cardiovascular death with estradiol use
- 72% increase in insulin resistance after 1 year; additional 9% in year 2
- Reduced brain volume and slower processing speed with long-term use
- Cognitive decline and elevated depression markers over time
- Only 0–24% retain sperm production after starting estrogen
- 6.6× higher incidence of multiple sclerosis
- Case reports of pancreatitis, autoimmune flare-ups, and brain tumors (meningioma)
The review emphasizes that many of these risks are under-recognized in clinical practice, raising urgent concerns about safety and informed consent.
- Schwartz, L., Lal, M., Cohn, J., Mendoza, C. D., & MacMillan, L. (2025). Emerging and accumulating safety signals for the use of estrogen among transgender women. Discover Mental Health, 5(1), 1-17. [Link] ↩︎