A little bit. I did a lot of research and also talked to people at my gym (non-commercial) and online who were experienced with it, and I got my bloods done beforehand to catch any unknown flags (this is vital according to almost every level headed person I talked to). I was fairly confident that as long as I got good grade test and the correct inhibitors that it would be fine. And it was, no side effects at all really.
Note that this was with test injections, not just orals. Orals only can fuck you up apparently.