Steroids are anabolic and androgenic synthetic variations of the male sex hormone, testosterone. To answer the question what do steroids do, one should look at each mechanism of action and the cells affected once the steroids are available in the circulation. Steroids, like most drugs, have both bad effects and desirable effects.
Anabolic steroids work similarly to endogenous testosterone. The anabolic action is mediated by the binding of the steroid to androgen receptors in muscles and adipose tissue. This leads to increased synthesis of proteins with increased retention of nitrogen in the body. When combined with intense physical exercises, this action leads to muscle bulking, increase in muscle strength and exercise tolerance.
The other anabolic effect of steroids is lipolysis. This is breakdown of fat to small fatty acids with release of energy. The result is a slimmer physique with increased energy to sustain muscular hypertrophy. Steroids act on kidneys to produce higher quantities of erythropoietin hormone. Erythropoietin usually acts on the bone to lead to increased red cell production. Red cells are used as oxygen carriers in the human body. This translates to more oxygen being availed to muscles in people on anabolic steroids. There is faster recovery of the muscles from anaerobic exercise hence stronger muscles and resilience.
The androgenic effect of steroids is increase in male sexual characteristics. This is associated with hair distribution, deepening of the voice and sexual arousal. However, there are associated side effects from these androgenic effects. This includes development of acne. This is because of increased numbers of sebaceous glands leading to increased sebum production and finally clogging of skin pores. Steroids also increase the rate of balding in men with a genetic predisposition to the male pattern balding.
Other undesirable effects include gynecomastia and increased body fat. This is mediated by estrogen. Testosterone undergoes aromatization to estrogen which is responsible for breast engorgement and pain. The effects on the brain lead to restlessness, agitation, insomnia, loss of appetite and fatigue. However, once stopping the use of anabolic steroids, the side effects resolve. It is also important to use steroids in their right dosages.