A 25 mg dose maintained serum T concentration within the physiological range for almost 24 h.
Most men are using much higher doses such as 100-200 mg/application.
Where your SHBG sits, the dose used, and how well you absorb the T will have a significant impact on TT/FT level achieved.
Even then the only way to know where your T level truly sits on such protocol (once daily scrotal AM application) is to test at peak (2 hrs post-application) and true trough (24 hrs).
If you are willing to spend the $$$ I would test at 2 hrs, and 24 hrs post-application, and in order to do such, you would need to apply the T cream around 9 am.
Would be interesting to see where levels sit at 2 hr, 12 hr, and 24 hr but highly doubtful any labs operate from 7 am-9 pm.
DISCUSSION
This study provides a pharmacokinetic profile of three doses of testosterone administered to the scrotal skin in a cream formulation. Application of the testosterone cream produced a rapid rise in serum testosterone peaking around 2 h after administration with a dose-dependent peak concentration, but not any consistent relationship between time of peak and testosterone dose. At the lowest dose (12.5 mg), the serum testosterone concentrations were maintained in the physiological range for at least 12 h and with the 25 mg dose maintained serum testosterone concentrations within the physiological range for nearly 24 h concentration.
