In very rare cases, anabolic/androgenic steroids have been associated with priapism, a condition characterized by a prolonged erection that does not return to a flaccid state within four hours. Priapism is a potentially very serious condition that may require medical or surgical intervention.

If left untreated, priapism can lead to permanent penile damage, erectile dysfunction, and even gangrene, which may necessitate the removal of the penis. When priapism is related to steroid use, testosterone is usually the responsible agent. Additionally, this condition appears to be more frequent in younger patients undergoing treatment for hypogonadism. This may be due to the rapid growth of the male reproductive system, which has not yet been exposed to high levels of stimulation. In adult steroid abusers, priapism is highly unlikely to occur.