Many transmasculine and gender diverse people assigned female at birth people use testosterone as gender-affirming hormone therapy, which is associated with significant changes to sexual and reproductive health. Additionally, transmasculine people experience significant barriers to accessing gynecological care. This study examined the perceived role of testosterone in individuals' gynecological health and how testosterone use shaped access to gynecological care for transmasculine people. We conducted in-depth qualitative interviews with 28 transmasculine and gender diverse adults currently using testosterone in the United States. Participants were recruited through PRIDEnet, a national community engagement network of LGBTQIA+ individuals and organizations. Data were analyzed using thematic analysis. Participants described a range of gynecological concerns, most commonly pelvic pain, genital atrophy, and recurrent urogenital infections. Six interrelated themes emerged: erasure, authority of knowledge, navigating uncertainty regarding testosterone's gynecological effects, prolonged and fragmented care pathways, cumulative exposure, and resistance and agency. Informational, institutional, and identity erasure frequently limited provider knowledge and constrained clinical decision-making, while conflicts over the authority of knowledge privileged diagnostic certainty over embodied experience. These dynamics contributed to prolonged healthcare journeys characterized by repeated referrals, excessive testing, unresolved symptoms, and diagnostic uncertainty. Repeated exposure to dismissive and delayed care, and care that was not trauma-informed accumulated, becoming embodied as medical trauma, overwhelm, disengagement from care, and diminished well-being. Despite these challenges, participants engaged in resistance and agency through self-advocacy and community knowledge. Improving gynecological care for transmasculine people requires expanded research on the gynecological effects of testosterone, improved provider education, and trauma-informed, trans-competent care models that value embodied patient knowledge.