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 . 
Dianabol is also capable of interaction with the enzyme aromatase resulting in the possibility of estrogenic side effects. Gynecomastia may become apparent even very early into a cycle, so the user must always ensure that they have the necessary drugs to treat the condition at the earliest possible opportunity. A Selective Estrogen Modulator (SERM) such as Tamoxifen (brand name Nolvadex) is usually used in these instances, perhaps with the addition of an anti-estrogen such as Proviron or Arimidex which will help hinder further estrogenic conversion. (For more information see the article Combating Oestrogens & Progesterone ).
As an example, should you choose to run a cycle that includes both Dianabol and Anavar, you will need to be extremely careful when it comes to overlapping them. The two are both hepatotoxic, which means they will cause liver damage. You will need to consider this carefully when it comes to choosing cycle lengths. If you take Dianabol for four weeks at the beginning of your cycle, then make the switch to Anavar, you should limit your Anavar use to four weeks, as well. This reduces your entire cycle time to eight weeks, which helps to alleviate some of the risk of liver damage.