The most commonly used AAS in medicine are testosterone and its various esters (but most commonly testosterone undecanoate , testosterone enanthate , testosterone cypionate , and testosterone propionate ),  nandrolone esters (most commonly nandrolone decanoate and nandrolone phenylpropionate ), stanozolol , and metandienone (methandrostenolone).  Others also available and used commonly but to a lesser extent include methyltestosterone , oxandrolone , mesterolone , and oxymetholone , as well as drostanolone propionate , metenolone (methylandrostenolone), and fluoxymesterone .  Dihydrotestosterone (DHT; androstanolone, stanolone) and its esters are also notable, although they are not widely used in medicine.  Boldenone undecylenate and trenbolone acetate are used in veterinary medicine . 
Winstrol is a brand name of the synthetic anabolic steroid, stanozolol. Although no longer available in the . under the name of Winstrol, generic versions of stanozolol can still be found. Stanozolol is similar to testosterone and commonly used by veterinarians on debilitated animals (especially dogs and horses) to improve muscle growth, trigger red blood cell production, increase bone density and enhance appetite. It's approved by the . Food and Drug Administration (FDA) for treating anemia and hereditary angioedema (swelling of blood vessels) in people, although a prescription is needed. Winstrol (stanozolol) is a banned performance-enhancing drug, but still used widely by track and field athletes as well as bodybuilders — usually illegally. You should take stanozolol only with the permission and under the care of a physician.
Winstrol is hepatotoxic, and because of this, it should be used at the lowest effective dose for the shortest possible cycle. What’s more, you should consider using a supplement designed to provide some additional protection. Milk thistle is a highly recommended option; studies suggest it can provide an effective layer of protection when it is used for the entire length of your cycle. There are some other supplements on the market, such as Liver Care, which are blends of natural ingredients that have been shown to work together to prevent liver toxicity.