What is the optimal timing to draw a total testosterone level in a male patient with hypogonadism (low testosterone levels) taking 200 mg of testosterone (testosterone) every 14 days?

Optimal Timing for Testosterone Level Testing

For patients receiving 200 mg testosterone cypionate or enanthate every 14 days, draw the total testosterone level midway between injections—specifically on day 7 (one week after the injection)—targeting a mid-normal value of 500-600 ng/dL. 1, 2

Rationale Based on Pharmacokinetics

The timing recommendation is driven by the predictable pharmacokinetic profile of testosterone esters:

• Peak serum testosterone levels occur 2-5 days after intramuscular injection, with levels often rising transiently above the upper limit of normal 3, 1, 4
• Testosterone levels return to baseline by days 10-14 after injection 3, 1, 2
• Research demonstrates that after 200 mg testosterone enanthate injection, serum testosterone peaks on days 2-5, then declines to basal levels by days 13-14 5

Measuring at the midpoint (day 7) captures a representative level that reflects the patient's average testosterone exposure throughout the dosing interval, avoiding both the supraphysiologic peak and the subtherapeutic trough 1, 2.

Initial Monitoring Timeline

After starting testosterone therapy or changing the dose:

• First follow-up visit at 1-2 months to assess clinical response and consider dose escalation if symptoms persist with suboptimal levels 3, 2
• Formal testosterone level testing at 2-3 months after treatment initiation or any dose change to allow steady-state levels to be achieved 1, 2
• Subsequent monitoring every 3-6 months for the first year, then yearly thereafter once stable levels are confirmed 3, 1, 2

Target Testosterone Levels

• Aim for mid-normal range (500-600 ng/dL) when measuring at the midpoint between injections 1, 2
• If clinical response is adequate, no dose adjustment is needed even if levels are in the low-normal range 3
• If clinical response is suboptimal AND testosterone levels are low-normal or below, increase the dose 3, 2

Critical Pitfalls to Avoid

• Do not draw testosterone levels at the peak (days 2-5), as this will show supraphysiologic levels that do not reflect average exposure and may lead to inappropriate dose reduction 3, 5
• Do not draw levels at the trough (days 13-14), as testosterone may have returned to baseline or below, potentially leading to unnecessary dose escalation 3, 5
• Do not test too early after starting treatment—allow 2-3 months for steady-state levels before making dosing decisions 1, 2
• Do not test at random times of day for baseline assessments—morning levels (8-10 AM) are required for initial diagnosis, though timing of day matters less for monitoring established therapy 1, 2

Additional Monitoring Requirements

Beyond testosterone levels, monitor:

• Hematocrit at each visit—withhold treatment if >54% and consider phlebotomy 3, 1, 2
• PSA levels in men over 40 years—refer for urologic evaluation if PSA increases >1.0 ng/mL in first 6 months or >0.4 ng/mL per year thereafter 3, 1
• Digital rectal examination at each visit to assess for prostate abnormalities 3

Clinical Context

The 200 mg every 14 days regimen is FDA-approved and commonly used 4. Research confirms this dosage maintains eugonadal testosterone levels through day 11 and effectively suppresses LH to normal in hypogonadal men 6, 7. However, the wide fluctuations inherent to this regimen—with many patients achieving androgen concentrations above normal between days 2-7—underscore why midpoint testing is essential for accurate dose titration 5.