If the UFC hopes to reduce steroid use, the only real way is to actually punish people who get caught. One year bans are not quite enough, because all that is lost is one fight in their plans. Doing steroids to win may be worth the risk of losing one fight (which could be lost to injury anyway).
Not sure how to do it, but look at Justin Gaitlin ... No one wants to be him. It makes some people maybe believe that it isn't worth it to use (unless they are totally convinced you cant win without using). Punishments need to have teeth, otherwise the whole system could become a farce.