Journal article

Effect of Spironolactone and Cyproterone Acetate on Breast Growth in Transgender People: A Randomized Clinical Trial

LM Angus, SY Leemaqz, AK Kasielska-Trojan, M Mikołajczyk, JCG Doery, JD Zajac, AS Cheung

Journal of Clinical Endocrinology and Metabolism | ENDOCRINE SOC | Published : 2025

Abstract

Context: Transgender people with sex recorded male at birth desiring feminization commonly use cyproterone acetate or spironolactone as antiandrogens with estradiol, but the optimal antiandrogen is unclear. Objective: We aimed to assess the effect of antiandrogens on breast development. We hypothesized this would be greater in those treated with cyproterone acetate than spironolactone due to more potent androgen receptor antagonism and suppression of serum total testosterone concentrations. Methods: A randomized clinical trial was conducted between 2020-2022 at an outpatient endocrinology clinic. Transgender people aged 18+ years old commencing feminizing gender affirming hormone therapy wer..

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University of Melbourne Researchers

Grants

Awarded by RACP Foundation


Funding Acknowledgements

L.M.A. is supported by the Research Training Program Scholarship from the Australian Government. ASC is supported by an Australian Government National Health and Medical Research Council Investigator Grant (#2008956). This study was funded by the Austin Medical Research Foundation, Endocrine Society of Australia Postdoctoral Award and the Royal Australasian College of Physicians Foundation Cottrell Research Establishment Fellowship Award.