Context: Symptoms and signs consistent with androgen deficiency and low testosterone levels are recognized frequently in clinical practice. Recent population-based epidemiological studies indicate that low testosterone levels in men are associated with increased morbidity and mortality. The clinician must be able to counsel patients to help them determine whether testosterone replacement therapy is appropriate for them.
Evidence acquisition: The authors have conducted a literature search in PubMed, and we have reviewed references in the multiple systematic reviews and meta-analyses that have been published on this topic.
Evidence synthesis: We have attempted to provide the reader with an appreciation of the evidence that can be used to support the diagnosis of androgen deficiency, the efficacy of treatment, the potential risks of treatment, the therapeutic options, and the recommendations for monitoring treatment.
Conclusions: We think that published clinical experience justifies testosterone replacement therapy in males who have not initiated puberty by age 14 and in males with low testosterone levels due to classical diseases of the hypothalamic-pituitary-gonadal axis. The benefit:risk ratio is less certain in older men and in those with chronic diseases associated with low testosterone levels. The decision to treat in this setting is much more controversial because there are few large clinical trials that have demonstrated efficacy and no large clinical trials that have determined potential risks of increasing the incidence of clinical prostate cancers or cardiovascular events. We provide a critical review of the evidence that supports treatment and potential risks and ways to reduce the risks if the physician and patient elect testosterone replacement.