# Comparison of different testosterone formulations discontinuation and dose spacing on hematocrit and testosterone levels in transgender individuals with erythrocytosis

## TL;DR

This study compares how stopping or spacing testosterone treatments affects blood levels in transgender men with high red blood cell counts.

## Contribution

The study provides new insights into the effectiveness of discontinuation and dose spacing of testosterone formulations in managing erythrocytosis.

## Key findings

- Discontinuing testosterone cypionate led to greater decreases in hematocrit, hemoglobin, and testosterone levels compared to undecanoate.
- Discontinuing testosterone undecanoate reduced hematocrit and hemoglobin but not testosterone levels.
- Dose spacing in testosterone cypionate users did not significantly reduce hematocrit or hemoglobin levels.

## Abstract

This study aimed to compare the effect of Gender Affirming Hormone Therapy with Testosterone (GAHT-T) discontinuation and dose spacing on Hct, hemoglobin (Hb) and total testosterone levels in users of testosterone cypionate and testosterone undecanoate.

This retrospective cohort analyzed data collected from the medical records of trans men older than 18 years who developed erythrocytosis during GAHT-T between 2020 and 2023. Participants were divided into three groups according to formulation in use when the diagnosis of erythrocytosis occurred and analyzed according to therapeutic approaches: discontinuation of GAHT-T for 3 months or, for the testosterone cypionate fourthly users, dose spacing.

A total of 49 trans men (mean age, 28.0 ± 7.8 years) were diagnosed with erythrocytosis, totalizing 104 tests. After discontinuing GAHT-T, a greater decrease in Hct, Hb and total T levels was observed in the testosterone cypionate (Cip 14 and Cip 28) users than in the testosterone undecanoate users (Und90). In Und90, discontinuation resulted in decrease of Hct and Hb levels, without difference in total T levels. Cip14 and Cip28 exhibited greater reductions in the Hct level than Und90 did with discontinuation. In Cip14, dose spacing had no effect on decreasing Hb, Hct and total T levels.

Discontinuation of testosterone undecanoate for 3 months in trans men undergoing GAHT-T who had developed erythrocytosis reduces hemoglobin and hematocrit levels without a significant reduction in testosterone levels. Dose spacing in fortnightly testosterone cypionate users was not effective to reduce hematocrit and hemoglobin.