Oxandrolone Use in Trans-Masculine Youth Appears to Increase Adult Height: Preliminary Evidence.

Early use of oxandrolone and gonadotropin-releasing hormone analogs has been shown to increase adult height in patients at risk for short stature, but use in trans-masculine (TM) youth to augment height has not been explored. The purpose of this study was to identify the impact of oxandrolone on adult height in TM youth. This was a single-center, retrospective chart review of TM patients seen between 2013 and 2018. Hormone regimens, heights, mid-parental height, and bone ages were recorded. We examined correlations between adult height and age at the initiation of treatment or with the age of referral (in untreated patients). Of TM patients, 154 had achieved adult height, including 34 who received oxandrolone, 42 who reached adult height before starting gender-affirming hormone therapy (GAHT), and 14 who received no treatment. Adult height correlated inversely with age at hormone initiation in oxandrolone-treated patients only ( = 0.001). Each earlier year of treatment yielded a 2.3 cm increase in adult height. Those who started oxandrolone younger than the median age achieved an adult height of 169.6 ± 6.4 cm compared to 162.1 ± 6.0 cm in those starting later than the median age ( < 0.001), 164.6 ± 4.8 cm in those receiving no treatment ( = 0.02), and 163.9 ± 6.5 cm in those receiving all other regimens ( < 0.001). Early use of oxandrolone may augment adult height in TM youth. Height discussions should be part of comprehensive GAHT counseling.