Superdrol is a powerful anabolic designer steroid brought to market in 2005, however due pressure by the FDA, the original Superdrol was pulled and is no longer available. Like many other compounds, it has been made available again through the production of clones such as M-Drol (Competetive Edge Labs) and Methadrol (iForce Nutrition).
These clones are the most popular and common superdrol clones. They're both the same active compound (2a, 17a Dimethyl Etiocholan 3-One, 17b-Ol). Since the original Superdrol is not available, going with a clone is the only option, however quality clones will produce identical results to the original Superdrol.
Superdrol is perhaps the most powerful compound available on the legal market, as well as one of the most toxic. Superdrol is only for advanced users that previous experience with prohormone cycles and several years of proper lifting and dieting.
There are several products based on the Supderdrol compound that have slight variations that may result in better/lesser gains and or a reduced/increased risk of side effects.