Anabolic steroids are a class of natural and synthetic steroid hormones that promote cell growth and division, resulting in growth of muscle tissue and sometimes bone size and strength. Steroids act in different ways on the body to promote muscle growth, and every steroid has androgenic and anabolic properties. It is because of this, they are properly referred to in medical texts as AAS (anabolic/androgenic steroids). Testosterone is the best known natural anabolic steroid, as well as the best known natural androgen.
