Side-effects are not expected because testosterone therapy aims to bring a man’s testosterone levels back to normal. However, testosterone therapy can increase the growth of the prostate gland which can make the symptoms of benign prostate enlargement (such as needing to urinate more often) worse. In the case of prostate cancer, testosterone therapy is not used because of concerns that it can make the tumour grow. Too high a dose of testosterone can lead to acne, weight gain, gynaecomastia (breast development), male-pattern hair loss and changes in mood. Any side-effects should be managed by a doctor and the testosterone dose lowered.