From the Research
For patients using estrogen gel, it's recommended to measure estradiol (estrogen) levels 12-24 hours after application, just before the next scheduled dose, to accurately assess the trough level, as supported by the study 1. This timing provides the most accurate assessment of the lowest concentration in the blood before the next dose is administered. When initiating therapy, wait at least 2-3 weeks of consistent use before testing to allow hormone levels to reach steady state, as seen in the study 2. For dose adjustments, allow 2-4 weeks on the new dose before retesting, to ensure reliable monitoring of hormone levels. It's essential to be consistent with both the timing of gel application and blood draws for reliable monitoring, as highlighted in the study 3, which notes the potential for skin contamination to distort plasma oestradiol measurements. Morning blood draws are typically preferred for consistency, and this timing recommendation helps clinicians accurately assess whether the current dosage is providing appropriate estrogen levels, as measurements taken too soon after application would show artificially high peaks rather than the sustained therapeutic level, as demonstrated in the study 4. Some key points to consider when measuring estradiol levels in patients using estrogen gel include: