Although there is no evidence that long term use of testosterone therapy can cause prostate cancer, testosterone may accelerate pre-existing prostate cancer. Testosterone therapy should not be used by men with active prostate cancer or a history of prostate cancer, or by men with the very rare male breast cancer, because testosterone can stimulate these cancers to grow.
Because testosterone replacement therapy impairs production of sperm, it should be used with caution in men with fertility concerns. Other conditions can potentially be made worse by testosterone therapy, including sleep apnoea, severe benign prostatic hypertrophy
, severe congestive heart failure, or high red blood cell counts (erythrocytosis).
Regular checks on your prostate health during testosterone treatment are recommended as part of routine health care. The amount of red blood cells in the blood should also be checked periodically.
Abuse or overuse of testosterone treatment can be dangerous. For example, using higher than replacement doses to increase muscle bulk can lead to impotence, liver disease, heart attack, and stroke.
Before starting any new treatment, be sure to tell your doctor about any other medication you are taking.