Yeah of course you gain weight, you are gaining water weight, once the source direct source (creatine) is gone from your body the water stops going to the muscles. Hence you loose this water weight and will drop back in weight and your bulk will go down, obviously you dont loose the muscle you gained while taking it unless you flat out stop lifting after you stop taking it but you will loose the bulk you had while taking it and will drop back in weight so i dont see why youd take it. Might as well do it the natural way and eat right work out and take a vitamin. Ppl these days look for instant gratification but the fact is building muscle takes years and taking supplements in the long run just hurts you. Talk to any one who has lifted for years and theyll tell you, in the short run a supplement will help but youre better of eating right, taking a whey and a mass building protein and getting your ass in the gym 5 days a week.