What are the target trough testosterone (T) levels for trans men undergoing testosterone therapy?

Target Trough Testosterone Levels for Trans Men

For transgender men undergoing testosterone therapy, the target trough testosterone level should be maintained within the typical physiological range for cisgender men of 300-1,000 ng/dL. 1

Recommended Target Levels and Monitoring

• The commonly recommended hormone therapy for transmasculine people aims to bring testosterone levels into the typical physiological range for cisgender men (300-1,000 ng/dL) 1
• To minimize health risks, plasma testosterone levels should be kept within this physiological range during hormonal treatment 2
• Regular monitoring is essential - it is recommended that transgender men under androgen therapy be monitored every 3 months during the first year of treatment and then every 6 to 12 months 2
• Trough levels should be measured at the appropriate time based on the testosterone formulation used (typically right before the next scheduled dose) 3

Administration Routes and Formulations

• Testosterone regimens for trans men consist of several options:

  • Injectable esters (most commonly administered subcutaneously for patient comfort) 1
  • Gels and patches (transdermal) 1
  • Testosterone undecanoate (long-acting testosterone) - though this raises concerns of pulmonary oil microembolism and anaphylaxis 1

• Injectable formulations are the most commonly used, particularly testosterone cypionate or testosterone enanthate 2

Expected Effects and Timeline

• Male physical characteristics typically begin to appear in almost all users after 6 months of therapy 2
• Maximum virilization effects are usually achieved after 3-5 years of regular hormone use 2
• Desired effects include:
  • Lowered voice pitch
  • Increased lean muscle mass and strength
  • Decreased fat mass
  • Increased libido 1, 4
  • Cessation of menstruation (typically within the first year of treatment) 5
  • Clitoral enlargement 4
  • Reduction in gender dysphoria, perceived stress, anxiety, and depression 4

Monitoring for Adverse Effects

• Regular monitoring should include:
  • Hematocrit/hemoglobin - testosterone therapy commonly causes erythrocytosis, particularly with injectable formulations 3, 6
  • If hematocrit rises above the reference range, consider temporarily withholding therapy, reducing the dose, or performing phlebotomy 3
  • Lipid profiles - testosterone may increase triglycerides and LDL cholesterol while decreasing HDL 1, 4
  • Blood pressure - testosterone may increase blood pressure 1
  • Liver function tests - increases in transaminases may occur 6

Important Considerations and Potential Risks

• Inadequate dosing of testosterone may have a negative impact on bone density in trans men 1
• Risk of erythrocytosis can be reduced through:
  • Smoking cessation
  • Weight loss (if BMI is high)
  • Switching to a transdermal route of administration 1
• Recent research suggests that even low-dose testosterone administration (≤62.5 mg/week) can be sufficient to increase lean body mass in trans men, while potentially reducing side effects 5
• Despite concerns about cardiovascular risk factors, current evidence suggests little to no impact on cardiovascular outcomes in trans men 1

Dosing Considerations

• Dose should be adjusted based on serum testosterone levels, aiming for the mid-normal range 3
• Some clinicians use a lower starting dose and gradually increase to minimize side effects while still achieving desired masculinization 6
• Recent evidence suggests that achieving testosterone levels within the target range is a prerequisite for the safety of gender-affirming treatment 6