Timing of Testosterone Level Monitoring After Starting Weekly Injections
Recheck testosterone levels 2-3 months after initiating weekly testosterone injections, with blood drawn midway between injections (day 5-7 for weekly dosing) to accurately assess treatment efficacy. 1
Initial Monitoring Timeline
The first follow-up visit should occur at 1-2 months to assess clinical response and consider dose adjustments, but formal testosterone level testing should be performed at 2-3 months after treatment initiation. 1
This 2-3 month timeframe also applies after any dose change, allowing sufficient time for steady-state levels to be achieved. 1
After the initial monitoring period, subsequent visits should occur at 3-6 month intervals during the first year, then yearly thereafter. 1
Optimal Blood Draw Timing
For weekly testosterone cypionate or enanthate injections, measure levels on day 5-7 after injection (midway between doses) rather than at peak or trough. 1
Peak serum testosterone occurs 2-5 days post-injection, with return to baseline by 10-14 days, creating significant fluctuations with traditional dosing schedules. 1
Midpoint measurement provides the most accurate assessment of average testosterone exposure and treatment adequacy. 1
Avoid measuring at trough (just before next injection) as this may falsely suggest inadequate dosing, or at peak (2-3 days post-injection) which may overestimate average exposure. 1
Target Levels and Interpretation
Target testosterone levels should be in the mid-to-upper normal range for optimal treatment response. 1
If clinical response is suboptimal and testosterone levels are in the low-normal range, increase the dosage with careful monitoring. 1
Testosterone levels should ideally show less than 10% variation between measurements to confirm stability. 1
Comprehensive Monitoring Beyond Testosterone
At the 2-3 month visit and subsequent follow-ups, also assess:
- Symptomatic response to treatment, including sexual function, energy, and mood. 1
- Hematocrit or hemoglobin levels - if hematocrit rises above the reference range, consider temporarily withholding therapy, reducing dosage, or performing phlebotomy. 1
- PSA levels - testosterone replacement may unmask occult prostate cancer. 1
- Physical examination including digital rectal examination. 1
Common Pitfalls to Avoid
Do not measure testosterone levels too early (before 2 months) - levels may not yet be at steady state and dose adjustments based on premature measurements can lead to over- or under-treatment. 1
Do not draw blood at random times between injections - this creates inconsistent and uninterpretable results due to the pharmacokinetic fluctuations of injectable testosterone. 1
For patients previously on GnRH agonists, do not measure testosterone until levels have plateaued - recovery can take a median of 16.6 weeks and is highly variable. 1