Impact of testosterone on vaginal health in transmasculine people: a systematic review

Introduction Testosterone is the mainstay of gender-affirming hormone therapy for transmasculine people. Administration of testosterone suppresses circulating estrogen and leads to the development of male secondary sex characteristics, but the impact of testosterone on the vagina and the symptomatic impact of these changes is largely unknown. Current treatment of vaginal symptoms in transmasculine people is informed by evidence for treating genitourinary syndrome of menopause. The objective of this systematic review is to evaluate evidence for the impact of testosterone on the vagina of transmasculine individuals and the assessment and management of these changes.Methods Medline, Embase, CINAHL, UpToDate, Trip Medical Database, and Cochrane Library of Systematic Reviews were searched up to April 2025. Manuscripts concerning the vagina of transmasculine people using testosterone were included. Studies focused on cis women or trans women were excluded. Reference lists of the identified studies were searched for the inclusion of additional studies. Expert opinion was sought to identify any unpublished literature relevant to this review. The Critical Appraisal Skills Programme (CASP) checklists were used to assess bias. Data were extracted and tabulated by a single researcher.Results Fourteen papers were included. Testosterone use is associated with a vaginal microbiome depleted in Lactobacilli sp. The vaginal epithelium of transmasculine individuals using testosterone shows atrophic changes and shifts in epithelial cell differentiation. A single cohort study showed topical estrogen reduced vaginal symptoms and increased colonization with Lactobacilli sp. in the vagina of transmasculine people.Discussion There is a lack of robust evidence for the impact of testosterone on the vagina of transmasculine individuals and for the assessment and treatment of vaginal symptoms. Future collaborative research with members of the transmasculine community is needed, with a focus on associated symptoms. Standardized assessment criteria must be validated in transmasculine people to evaluate the impact of testosterone on the vagina and the treatment of vaginal symptoms.