Timing of Testosterone Level Monitoring After Starting AndroGel
Testosterone levels should be checked at approximately 14 days and 28 days after starting AndroGel to ensure target levels have been achieved, with subsequent monitoring every 6-12 months once stable therapeutic levels are confirmed. 1
Initial Monitoring Protocol
The FDA-approved labeling for testosterone gel 1.62% provides explicit timing guidance:
- First check: 14 days after initiation - Draw pre-dose morning serum testosterone to assess initial response 1
- Second check: 28 days after initiation - Repeat pre-dose morning testosterone to confirm appropriate dosing 1
- Dose titration should occur based on these measurements, with adjustments made to achieve target testosterone levels of 350-750 ng/dL 1
Target Testosterone Levels
The goal is to achieve total testosterone levels in the middle tertile of the normal reference range (450-600 ng/dL). 2
Specific dose adjustment criteria based on pre-dose morning levels:
- >750 ng/dL: Decrease dose by 20.25 mg 1
- 350-750 ng/dL: Continue current dose 1
- <350 ng/dL: Increase dose by 20.25 mg 1
Ongoing Monitoring Schedule
After achieving stable therapeutic levels, testosterone should be measured every 6-12 months while on therapy. 2
This ongoing monitoring ensures:
- Maintenance of therapeutic testosterone levels 2
- Early detection of supraphysiologic levels that could increase adverse event risk 2
- Assessment of continued clinical benefit, as therapy should be discontinued if target levels are achieved without symptom improvement after 3-6 months 2
Critical Timing Considerations
All testosterone measurements must be drawn as pre-dose morning samples to ensure accuracy and consistency. 1
- Testosterone gel reaches steady-state within the first 24 hours of application 3
- Morning timing is essential due to diurnal variation in testosterone levels 2
- The rapid achievement of steady-state (approximately 1 day) with testosterone gel allows for earlier assessment compared to injectable formulations 4
Common Pitfalls to Avoid
- Do not wait longer than 4 weeks for initial assessment - The 14-day timepoint is specifically designed to allow early dose optimization 1
- Do not check levels at random times of day - Only morning pre-dose samples provide reliable data for dose adjustment 1
- Do not continue therapy indefinitely without monitoring - Patients achieving target levels without symptom improvement by 3-6 months should discontinue therapy 2