According to everything I have studied up on TRT, it takes between 1 and 3 days for your body to begin sufficiently breaking down the suspension oil and to absorb/use the testosterone. This is a highly individualized thing however, because everyone's metabolic rate is different and this is what determines how much or how little you need to carry you through until the next dose, and also how often to dose too (because that determines how slow or quickly your body is able to break down that suspension oil). So your own metabolic rate is actually the primary variable of TRT dosing and schedule.
That stated, I get my T level checked exactly a week on the day from the previous injection (bi-monthly/2 weeks dosing schedule). That is actually the standard for TRT monitoring through labs. For example, I dose on Thursday. So the following Thursday, I go get the lab draw. No exceptions. Even if I really don't want too, I go and get it done on that day.
Anyway. The reference range levels of total testosterone that my Endo wanted me to end up in after seven days from a dose was between 400 and 800. And it turned out to be 800 as the optimal for me (any lower than that, I'm too lazy and tired-like and the last four days of the cycle really drag, but any higher, I'm a bit too amped up and edgy).
It doesn't take very much to put me in that range either. Just a bit over half of the stated dose amount of the vial is about what it takes for me. And sometimes, for reasons we don't know exactly why yet, that same amount in my quad muscle (vastus lateralis) can skyrocket my TT to an inhuman 1,356! Whereas that same amount, in my glute muscles, will average 800 every time with the seven day post-injection lab schedule.
Just more proof of how highly individual TRT is and how widely variable levels can go.
Hope you get your dose and schedule sorted. We're still working on mine, just over six months after starting for me. It can be a bit frustrating but I'm sure once its figured out, it's all smooth sailing from there.
But yeah, maybe talk to your doc about trying to get your TT checked the following insert-day-of-week-here to see where you fall into the 400-800 reference range at the mid-point of your dose/schedule.
