this is something i'd like to get an answer to also, but i think it depends on how long you've been on, and how much you've been taking.
i have a close friend that was a top national level competitor for years, and he finally gave competing a rest because him and his wife decided to start a family. i'm not really sure how long he stayed on for, but i do know his pre contest and off season cycles were reasonable. nothing ridiculous at all.
it took him over a year to balance out again. during that time i remember him telling me he had a very weak sex drive. wish i knew what his T levels were during that time...i'm sure they were very low.
needless to say getting your test levels to come back to normal after being on for a long peroid of time can be brutal.
i would think it has a lot to do with how long you've been surpressing your bodys natural testosterone production.