When do you notice effect of androderm (testosterone) patch?

Days to weeks. All testosterone replacement products get into your system pretty quickly so you should start noticing something shortly. With that said, it also depends upon how low you were to start and how large a dose/patch you're given/taking. In other words, there's less noticeable change going from b+ to a- as compared to moving from d- or even f to an strong b grade. But that's also dose dependent.