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

Purpose: 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. Methods: 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). Results: 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 (p = 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 (p < 0.001), 164.6 ± 4.8 cm in those receiving no treatment (p = 0.02), and 163.9 ± 6.5 cm in those receiving all other regimens (p < 0.001). Conclusions: Early use of oxandrolone may augment adult height in TM youth. Height discussions should be part of comprehensive GAHT counseling.