Potential side-effects must be monitored in all patients so that the benefits of treatment will outweigh its adverse effects. This is consistent with guidelines by Singapore Urological Association on testosterone replacement therapy. 

1. Lipid and cardiovascular safety

The complex relationships between androgens and cardiovascular risk factors have not been completely elucidated. Hence, caution is advised when supplementing androgens in men with significant risk factors for cardiovascular disease

2. Haematology

Testosterone stimulates the bone marrow production of red blood cells and may result in a significant increase in red blood cell mass and concentration (condition called polychthaemia). Dose adjustments may be necessary if the blood concentration rises but rarely, testosterone replacement has to be discontinued due to polycythaemia.

3. Prostate safety

There are no clear relationship between testosterone replacement therapy and prostate cancer. However, there are few anecdotal reports of prostate cancer linked to this therapy. More long-term studies are needed to clarify this issue.

Currently, the suspicion of prostate cancer is an absolute contraindication for ART.

Examination of the prostate should be done routinely and blood PSA levels should be checked annually. Suspicious digital rectal examination, rapidly increasing or high PSA levels warrant termination of testosterone replacement and referral to the urologist.

Patients with significant bladder outlet obstruction due to prostate enlargement represent relative contraindication to testosterone therapy. Severe outlet obstruction may necessitate intervention by the urologist before replacement therapy is initiated.

4. Male breast swelling (gynaecomastia)

Testosterone may be converted to estradiol and lead to changes in sex hormone binding globulin levels. These may cause gynaecomastia.

5. Mood and behavior

Testosterone replacement normally results in improvements in mood and well-being. The development of negative behavioral patterns during treatment, which can occur rarely, necessitates dose adjustment or discontinuation of therapy.

1. Restore sexual function, libido and sense of well-being. Studies have shown that testosterone replacement therapy improves erectile function in men who were previous non responders to phosphodiesterase 5 inhibitors

2. Optimize bone density to prevent osteoporosis and minimize the risk of fractures

3. Improves body composition by decreasing truncal obesity and improving muscle function

3. Pilot studies and ongoing clinical trials support the role of testosterone therapy in the management of all components of the metabolic syndrome and its associated diseases like diabetes mellitus and hypertension.