It affects everyone differently. My testosterone has actually been higher while using and I have stopped and had blood work done multiple times for drug tested bodybuilding and work. I am a goalie in hockey as well as a boxer and my reflexes have not slipped at all. I’m also preparing to open my own gym and would not say my iq has gone down (but I have not had this tested). The key is to use it in moderation and not let it control your life. Smoking before going to the gym, probably not a good idea. But smoking after a hard day of training and resting at home compared to going out and getting shitfaced all night is definitely a better option.