Related Experiment Video
Updated: Jan 17, 2026

Establishment of Rat Models Mimicking Gender-affirming Hormone Therapies
Published on: January 10, 2025
Frequency, Timing, and Management of Erythrocytosis in Adolescents Receiving Gender-Affirming Testosterone Therapy-A
Ashleigh McLean1,2, Monsurul Hoq3, Ken C Pang3,4,5
1Department of Endocrinology and Diabetes, The Royal Children's Hospital, Victoria, Australia.
Abstract:
Erythrocytosis is a well-described effect of testosterone therapy in adults, but less is known about this phenomenon in transgender and gender-diverse adolescents. To explore this further, we performed a retrospective study in 158 adolescents who received gender-affirming testosterone therapy from January 2007 to April 2020 at a pediatric gender service. Erythrocytosis (hematocrit [Hct] > 0.50 L/L) developed in 9.5% (15/158) of adolescents. Frequency increased with time; in the majority (67%, 10/15), erythrocytosis occurred in the second year of treatment. Overall, our findings indicate erythrocytosis occurs commonly in testosterone-treated transgender adolescents and support the need for regular ongoing monitoring of Hct.
More Related Videos
Related Concept Videos
Factors Affecting Erythropoiesis
Several factors influence the erythrocyte production rate, with tissue oxygen level being among the most critical. Intense exercise or high altitudes can cause tissue hypoxia, which triggers the kidneys to release more erythropoietin (EPO) into the bloodstream.
EPO then...
Signs of Puberty
Therapeutic Drug Monitoring: Affecting Factors
Testosterone: Functions and Regulation
Erythropoiesis
Hormonal Regulation

