Category: Testosterone • Page 2
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One year of cross sex hormone therapy causes robust increases in muscle mass and strength in transmen (females) but modest changes in transwomen (males)
Thigh muscle volume increased 15% in transmen, which was paralleled by increased quadriceps cross-sectional area (CSA) (15%) and radiological density 6%. In transwomen, the corresponding parameters decreased by –5% (muscle volume) and –4% (CSA), while density remained unaltered. The transmen increased strength over the assessment period, while the transwomen generally maintained their strength levels1:

- Wiik, A., Lundberg, T. R., Rullman, E., Andersson, D. P., Holmberg, et al. (2019). Muscle strength, size, and composition following 12 months of gender-affirming treatment in transgender individuals. The Journal of Clinical Endocrinology & Metabolism, 105(3). [Link] ↩︎
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Strength advantage over females is retained by male-to-female transitioners (transwomen)
A systematic review of 24 studies concluded that while male-female transitioners (transwomen) do experience some decrease in muscle mass; values for strength and muscle area in transwomen remain above those of biological women, even after 36 months of hormone therapy.
Figure one1:

The above graph show’s the performance difference between transwomen and biological women in various sports. A systematic review of 24 studies concluded that while male-female transitioners (trans women) do experience a decrease in muscle mass; values for strength and muscle area in transwomen remain above those of biological women, even after 36 months of hormone therapy2.
- Hilton, E. N. & Lundberg, T.R. (2021). Transgender Women in the Female Category of Sport: Perspectives on Testosterone Suppression and Performance Advantage. Sports Med 51: 199–214. [Link] ↩︎
- Harper J, O’Donnell E, Sorouri Khorashad B, et al . (2021). How does hormone transition in transgender women change body composition, muscle strength and haemoglobin? Systematic review with a focus on the implications for sport participation. British Journal of Sports Medicine ;55:865-872. [Link] ↩︎
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Transmen are four or five times more likely than females in general to suffer a heart attack
A 2019 study1 found that post-operative female-to-male transgender people were 4.9 times as likely to suffer a myocardial infarction (heart attack) than women in general.
Another study2 also found a somewhat smaller yet still large discrepancy, concluding that transmen were 3.69 more likely to suffer a heart attack than women in general.
- Alzahrani, T. Nguyen, T., Ryan, A., Dwairy, A. McCaffrey, J., Yunus, R., Forgione, J., Krepp, J., Nagy, C., Mazhari, R. & Reiner, J. (2019). Cardiovascular Disease Risk Factors and Myocardial Infarction in the Transgender Population. Circulation: Cardiovascular Quality and Outcomes 12 (4). [Link] ↩︎
- Nota, N.M., Wiepjes, C.M., de Blok, C.J.M., Gooren, L.J.G., Kreukels, B.P.D. & den Heijer, M. (2019). Occurrence of Acute Cardiovascular Events in Transgender Individuals Receiving Hormone Therapy: Results From a Large Cohort Study. Circulation 139: 1461-1462. [Link] ↩︎
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In one study, 11% of transmen who took testosterone developed a condition called erythrocytosis, which impacts red blood cells and slows the blood flow
A study1 of 776 transmen who took testosterone demonstrated that 11% of them developed erythrocytosis, a condition which slows the blood flow, and can lead to headaches, confusion, high blood pressure, nosebleeds, blurred vision, itching and fatigue.
- Madsen, M.C., van Dijk, D. Wiepjes, C.M., Conemans, E.B., Thijs, A. & den Heijer, M. (2021). Erythrocytosis in a Large Cohort of Trans Men Using Testosterone: A Long-Term Follow-Up Study on Prevalence, Determinants, and Exposure Years. The Journal of Clinical Endocrinology & Metabolism 106 (6): 1710–1717. [Link] ↩︎
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Long-term testosterone use in natal females can cause vaginal atrophy, which makes sex painful
A study1 of 16 female-to-male transgender individuals concluded that long-term testosterone administration leads to vaginal atrophy (Baldassarre et al., 2013). The study noted that:
Vaginal samples from FtM showed a loss of normal architecture of the epithelium, intermediate and superficial layers were completely lost, and glycogen content was depleted.
Vaginal atrophy, characterized by thinning of vaginal walls and poor lubrication of vaginal tissues, leads to tearing, micro abrasions, bleeding, and painful intercourse.
- Baldassarre, M., Giannone, F., Foschini, M., Battaglia, C., Busacchi, P., Venturoli, S., & Meriggiola, M. (2013). Effects of long-term high dose testosterone administration on vaginal epithelium structure and estrogen receptor-α and -β expression of young women. International Journal Of Impotence Research, 25 (5): 172-177. [Link] ↩︎
