Acceptable Testosterone Range for Women on Testosterone Injections
For adult women receiving testosterone injections (typically transgender men or those with gender dysphoria), target serum testosterone concentrations in the physiologic male range of 300–1,000 ng/dL, with mid-normal values of 450–600 ng/dL preferred. 1, 2
Target Testosterone Levels
The therapeutic goal is to achieve total testosterone between 300 ng/dL and 1,000 ng/dL, which corresponds to the typical physiological range for cisgender men. 2
Mid-normal concentrations of 450–600 ng/dL are preferred to optimize clinical response while minimizing adverse effects such as erythrocytosis. 1, 2, 3
These targets apply whether using intramuscular or subcutaneous administration routes. 4, 5
Timing of Testosterone Measurement
For injectable testosterone (enanthate or cypionate), measure serum testosterone midway between injections (e.g., days 5–7 for weekly dosing or days 7–10 for bi-weekly dosing). 1, 2, 3
Peak serum levels occur 2–5 days after injection, while levels return toward baseline by days 10–14, so mid-interval timing captures representative values. 1
Avoid measuring at peak (days 2–5) or trough (days 13–14), as these extremes do not reflect average exposure and may lead to inappropriate dose adjustments. 1
Monitoring Schedule
Check testosterone levels 2–3 months after treatment initiation or any dose change to assess whether target range has been achieved. 1, 2, 3
Once stable levels are confirmed on a given dose, monitor every 6–12 months. 1, 2
At each visit, also monitor hematocrit/hemoglobin, as erythrocytosis is a dose-dependent risk. 1, 2
Dosing Regimens to Achieve Target Range
Intramuscular testosterone enanthate or cypionate: 50–100 mg weekly or 100–200 mg every 2 weeks is the typical starting range. 1, 2, 3
Subcutaneous testosterone: 50–150 mg weekly achieves therapeutic levels equivalent to intramuscular administration across a wide BMI range. 2, 4, 5
Transdermal testosterone gel 1.62% (≈40.5 mg daily) is an alternative first-line option providing more stable day-to-day concentrations. 1, 2
Weekly dosing (whether IM or SC) provides more stable testosterone levels compared to bi-weekly administration, reducing the "roller-coaster" effect and potentially lowering adverse event risk. 2, 4
Evidence for Stable Levels with Subcutaneous Administration
In transgender men receiving weekly subcutaneous testosterone cypionate, mean total testosterone remained stable at 627 ± 206 ng/dL (range 205–1,410) and free testosterone at 146 ± 51 pg/mL (range 38–348) throughout the dosing interval. 4
Subcutaneous administration achieves therapeutic testosterone levels equivalent to intramuscular injections with doses of 50–150 mg weekly, demonstrating effectiveness across BMI 19.0–49.9 kg/m². 5
Safety Considerations
Withhold testosterone if hematocrit exceeds 54% and consider therapeutic phlebotomy in high-risk cases. 1, 2
Injectable testosterone carries a higher erythrocytosis risk (≈44%) compared to transdermal preparations (≈15%) due to supraphysiologic peak levels. 1, 2
Typical lipid changes include modest increases in LDL cholesterol and decreases in HDL cholesterol, though current evidence indicates minimal impact on cardiovascular outcomes in transgender men. 2
Common Pitfalls to Avoid
Do not target supraphysiologic levels (>1,000 ng/dL), as this increases adverse effects—particularly erythrocytosis—without additional clinical benefit. 2, 3
Do not measure testosterone at peak or trough times, as this leads to inappropriate dose adjustments based on non-representative values. 1
Do not assume all formulations require the same dosing; transdermal preparations have different pharmacokinetics than injectables and require separate titration. 1, 2
Do not continue doses that produce levels >1,000 ng/dL even if the patient reports feeling well, as supraphysiological levels increase hematologic and potentially cardiovascular risks. 2, 3