Well Arnold use to smoke so why not? Well because it lowers your testosterone which in turn changes your ratio (T to E). I personally don't like Deca without some sort of Testosterone, once and only once I had problems rasing the tent and that was from a 500mg PW of Deca only, 6 week cycle. If I were you I would not smoke or if it's just one of those things you can't live without only use on the weekends. BTW Arnold had such elevated test levels he probably could have smoked every day and never had to worry about it. If it hinders your gains is it worth it???