What are the target testosterone serum levels for transgender individuals undergoing Hormone Replacement Therapy (HRT)?

Target Testosterone Serum Levels for Transgender Individuals on HRT

For transmasculine individuals (trans men and transmasculine non-binary people), target testosterone levels should be maintained within the typical cisgender male physiological range of 300-1,000 ng/dL, with trough levels measured immediately before the next scheduled dose. 1, 2

Transmasculine Hormone Therapy (Trans Men/Transmasculine Individuals)

Target Testosterone Levels

• Standard dosing aims for serum testosterone concentrations of 300-1,000 ng/dL, matching the cisgender male reference range 1, 2, 3
• Trough levels (measured right before the next dose) should remain within this range to ensure adequate masculinization while minimizing adverse effects 2
• Dose adjustments should target the mid-normal range to optimize safety and efficacy 2

Testosterone Formulations Available

• Injectable testosterone esters (most commonly used, typically administered subcutaneously) 1
• Transdermal gels and patches 1
• Testosterone undecanoate (long-acting injectable) - use with caution due to risk of pulmonary oil microembolism and anaphylaxis 1, 2

Monitoring Schedule and Parameters

• Monitor every 3 months during the first year, then every 6-12 months thereafter 3
• Hematocrit/hemoglobin levels - testosterone commonly causes erythrocytosis, particularly with injectable formulations 2
  • If hematocrit rises above reference range, consider temporarily withholding therapy, reducing dose, or performing phlebotomy 2
  • Hemoglobin increases to male reference range within 3 months 1
• Lipid profiles - testosterone may increase triglycerides and LDL cholesterol while decreasing HDL 1, 2
• Blood pressure - testosterone may increase blood pressure 1, 2
• Bone density - inadequate testosterone dosing may negatively impact bone health 2

Risk Mitigation Strategies for Erythrocytosis

• Smoking cessation 1, 2
• Weight loss if BMI is elevated 1, 2
• Switching from injectable to transdermal route of administration 1, 2

Expected Timeline of Effects

• Most male physical characteristics develop within 6 months of therapy 3
• Maximum virilization effects typically achieved after 3-5 years of regular hormone use 3
• Voice deepening, body/facial hair growth, menstrual suppression, increased muscle mass, and clitoral growth occur progressively 1

Transfeminine Hormone Therapy (Trans Women/Transfeminine Individuals)

Target Testosterone Levels

• Most individuals achieve testosterone concentrations in the cisgender female reference range through combination estradiol and anti-androgen therapy 1
• The goal is testosterone suppression to female physiological levels, though specific numeric targets vary based on anti-androgen mechanism 1
• Peripheral androgen receptor antagonists (spironolactone, bicalutamide) may not necessarily lower testosterone concentrations despite blocking androgen effects 1

Important Caveats

• Avoid ethinyl estradiol - associated with higher VTE risk compared to bioidentical estradiol 1
• Progestins are not recommended by the Endocrine Society due to increased cardiovascular and breast cancer risk without proven benefit 1
• Testosterone therapy in trans men shows little to no impact on cardiovascular outcomes despite multiple metabolic risk factors 1, 2
• Trans women have elevated risk of VTE and cardiovascular events compared to cisgender populations 1