Stanozolol which is popularly marketed under the name Winstrol is a derivative of dihydrotestosterone, chemically altered so that the hormoneâ€™s anabolic (tissue-building) properties are greatly amplified and its androgenic activity minimized. Stanozolol is classified as an â€œanabolicâ€ steroid, and exhibits one of the strongest dissociations of anabolic to androgenic effect among commercially available agents. It also cannot be aromatized into estrogens. Stanozolol is the second most widely used oral steroid, succeeded in popularity only by Dianabol (methandrostenolone). It is favored for its ability to promote muscle growth without water-retention, making it highly valued by dieting bodybuilders and competitive athletes.