The physiological factors which contribute to impotence include a decreased production of natural testosterone by the testes as the exogenous steroid short circuits the natural endocrine feedback system. Occasionally, an athlete who uses high dosages of only anabolic items can have such an imbalance between anabolic and androgenic hormones that the androgenic effects that control the ability to maintain an erection, become diluted. This can be corrected by adding oral testosterone or another high androgen to the cycle in a moderate dose. Often times, impotence can occur after a steroid cycle, when the exogenous source of testosterone is removed leaving a lull in blood androgen levels. This is because the body has not recuperated its ability to produce testosterone on its own yet.
Testicular atrophy can also occur with steroid users.
This side effect does seem to be reversible and some avoid it altogether with intermittent shots of HCG during the cycle. More often, women have an increased libido as a result of steroid therapy. This is primarily due to the fact that testosterone is the precursor of the libido in women and an increased amount of androgens in their system can cause a markedly increased sex drive. It would be accurate to say that it does occur and that it is reversible, if not controllable altogether. Nearly all steroid users will have subnormal values in these areas during a cycle.