High testosterone levels in men may be caused by genetics, pituitary gland problems or from taking testosterone supplements or anabolic steroids. Some side effects of high testosterone levels are temporary and resolve when testosterone levels return to normal, but other effects may be permanent and require medical treatment. Men with high testosterone levels should have regular medical exams, including screenings for prostate cancer.
High testosterone levels in men may speed up the progression of male pattern baldness, which is permanent and non-reversible.
The sebaceous glands in the face that produce oil can be overstimulated by high testosterone levels in men, causing facial acne.
High levels of testosterone in men may cause aggressive behaviours, feelings of uncontrollable anger and rage, and violence against partners, pets and strangers.
Long-term side effects of high testosterone levels include liver damage, especially when the testosterone is taken in the form of oral anabolic steroids.
Infertility is a temporary side effect of high testosterone levels in men, due to reduced production of sperm and shrinking of the testicles.
High testosterone may cause the prostate to enlarge, which can result in pain and difficulty with urination.
According to the Mayo Clinic, high testosterone may cause faster growth of existing prostate cancer or cause a new prostate cancer to develop.