Winstrol is generally not preferred for building mass as it is highly anabolic and very slightly androgenic, an oral Steroid such as Dianabol is usually a better choice for people wanting to bulk up. Due to its ability to dramatically lower SHBG it can be used in a bulking cycle as a means to make other hormones more efficient, increase free testosterone and even solidify gains to a stronger degree but most of the people will find other steroids to be far more beneficial than winstrol in the long run. However some people are very sensitive to side effects of certain Steroids such as Dianabol, and would rather use Winstrol in a bulking cycle, while the weight gain wont be as dramatic as with Dianabol, with a proper high calorie diet, you can still see good results.
When it comes to the competitive bodybuilders supplementing those last few weeks before a show , the result is simply a fuller look; end of story. For the off-season athlete, with proper food intake and four to six weeks of supplementation, Anadrol results of a 20lb increase are not unheard of; in-fact, that's pretty standard. Even so, understand that is not going to be 20lbs of lean tissue; in-fact, it will probably be a lot of water. If you are to truly maximize your Anadrol results, a gain in 8lbs to 10lbs is probably more like it as it will be less water weight and a lot more lean tissue; understand, 10lbs is a massive gain if most of it is lean tissue; no one is actually gaining 20lbs of pure lean tissue in four to six weeks.