Of concern to any user of Winstrol during a cycle should be its intoxicating effect on the liver . The drug is a 17aa structured steroid , meaning it has been structured in a way which allows it to be orally bio-available, yet this has the negative effect of making Winstrol potentially harmful to the liver. It is therefore paramount the duration of a Winstrol cycle is limited, the dose of the drug is not excessive, the user does not stack it with other hepatotoxic compounds, does not drink alcohol whilst on cycle, and does not use Winstrol if they have an underlying medical condition which effects the livers health. There are supplements available which also help protect the liver (Milk Thistle, Liv-52 etc), and these would be advisable during any Winstrol cycle .
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 .