Testosterone and sexual function in men.

Testosterone (T) is deeply involved in every step of the male sexual response. However, the occurrence of sexual disorders cannot be automatically related to a decline in T levels. In fact, this relationship is complicated by organic, relational and psychological factors, which can independently impair sexual function. For example, it is recognized that erectile dysfunction (ED) can result from vascular damage as well as from low levels of T. T therapy (TTh) can improve sexual function but meta-analyses show that it improves erectile function only in men with ED and overt hypogonadism. Similarly, impaired sexual desire can result from a wide range of organic, relational and psychological factors, although it is recognized as one of the most specific symptoms of hypogonadism. Accordingly, low desire is improved by TTh in men with overt hypogonadism. The association between low T levels and delayed ejaculation has not been well studied and needs further confirmation, as does the role of TTh in such cases. Meta-analyses have found that TTh can improve orgasmic function in hypogonadal men. Clinicians should bear in mind that sexual dysfunctions have multifactorial causes and hypogonadism represents only one of these. Only hypogonadal men are likely to improve their sexual symptoms when treated with TTh. The assessment of serum T levels is mandatory before patients are prescribed TTh, as are the assessment and possible treatment of other concomitant conditions.