Anabolic steroids are synthetic, or human made variations of the male sex hormone, testosterone. The correct terminology is ‘anabolic-androgenic steroids’. Anabolic refers to muscle building and androgenic refers to increased male sex characteristics. The main function of anabolics is to enhance the process of metabolism and assimilation of those substances that go to the construction of tissues of a living organism, with simultaneous weakening of metabolic reactions associated with the disintegration of complex organic substances. Steroids stimulate protein metabolism. Anabolics activate a positive nitrogen balance, which also activates mineral metabolism, delaying the body the necessary potassium, phosphorus and sulfur for protein synthesis, which contributes to calcium retention in the bones. Steroids are derivatives of testosterone, so they have an androgenic effect, that is, they act on a type of male sex hormone. . In consequence, the formation of a male muscular figure (one of the key secondary sexual characteristics) is provided. Anabolics mimic the action of the male sex hormones – testosterone and dihydrotestosterone. Steroids accelerate the synthesis of protein inside the cells, which leads to severe hypertrophy of muscle tissue (this process is called anabolism). It is because of this that anabolics have gained great popularity in bodybuilding. The action of steroids is divided into two areas: anabolic activity and androgenic activity (as indicated above). Bodybuilders as well as athletes use steroids to enhance physical appearance, increase muscle mass and strength and also to reduce body fat and achieve a dry, hard, lean look with pronounced definition and vascularity. In medicine, representatives that are using these pharmaceutical preparations, use these for the observed conditions such as; after severe injuries, for post-operations or diseases and within the delayed healing of severe burns and wounds. These preparations are also used for conditions such as Osteoporosis and during the final stages of cancer. Simultaneously with steroid treatments, increased daily doses of macronutrients (especially protein), trace elements (especially calcium) and vitamins are required to be included in the diet. Although some steroids are still used today to treat certain medical conditions and illnesses, the use of steroids in sports and bodybuilding for athletic performance far outweighs the use of such compounds in the medical industry.