Anabolic steroids may block the binding of cortisol to its receptor sites, which would prevent muscle breakdown and enhances recovery. While this is beneficial while the athlete is taking the drug, the effect backfires when he stops taking it. Hormonal adaptations occur in response to the abnormal amount of male hormone present in the athlete's body. Cortisol receptor sites and cortisol secretion from the adrenal cortex increase.
Anabolic steroid use decreases testosterone secretion. People who stop taking steroids are also hampered with less male hormone than usual during the "off" periods. The catabolic effects of cortisol are enhanced when the athlete stops taking the drugs and strength and muscle size are lost at a rapid rate.
The rebound effect of cortisol and its receptors presents people who use anabolic steroids with several serious problems: (1) psychological addiction is more probable because they become dependent on the drugs. This is because they tend to lose strength and size rapidly when off steroids. To stave off deconditioning, athletes may want to take the drugs for long periods of time to prevent falling behind. (2) Long-term administration increases the chance of serious side-effects. (3) Cortisol suppresses the immune system. This makes steroid users more prone to diseases, such as cold and flu, during the period immediately following steroid administration.