Osteoanabolic Estrogen Therapy in a Transsexual Man

In 2008, a 31-year-old transsexual man seeking male-to-female sex-change treatment was studied to understand the effects of hormone therapy on bone mass. Initially, the patient had normal male characteristics and bone density. However, after 30 months on cyproterone (100 mg daily), his bone mass decreased by 5% per year, and a bone biopsy indicated high turnover osteoporosis. Subsequently, the addition of oestradiol valerate (2 mg daily) to his regimen resulted in a 4% annual increase in bone mass. In vitro tests showed that oestradiol stimulated osteoblastic cells isolated from the patient's biopsy tissue. These findings highlight the significant role of sex hormones, including oestrogens, in maintaining bone mass acquired during adolescence and suggest that oestrogens have an anabolic effect on bone in males.