Anabolic steroids, or anabolic-androgenic steroids, act like the male sex hormone testosterone. Steroids help to build lean muscle mass, and body builders use them to get more “bulk” on the body. Steroids also help body builders and athletes to train with more intensity and manage through longer and longer training sessions without having to take breaks. Body builders usually take steroids in cycles so that a period of taking steroids is followed by a break from the substances. Steroid use comes with side effects. Some are temporary, and some can be permanent. Because steroids act like testosterone in the body, they make the body act as if it is going through puberty. Typical effects include acne, the growth of body hair in men and women, loss of hair on the head (male pattern baldness), the growth of breasts in men, deepening of the voice, and menstrual problems or fertility problems in women. Steroid abuse can also cause impotence, shrinking of the testicles, and decreased sperm count.