Not that I am an expert or anything, but I do have some experience with this subject. It all depends on the ESTER of testosterone that was used. Most users like the longer duration esters (decanoate) that last for many weeks in the body. Those dont have a significant immediate effect. There ARE short duration testosterones that might have a quicker effect. Then there are testosterone ester blends, which combined different ones that give a quick boost plus a long duration effect as well.
All I will say is the experience I've had with monitoring some folks taking this stuff, is that there was no immediate effect. But who knows, maybe they have some super duper quick acting stuff these days