Negative Side Effects of Testosterone

Testosterone replacement therapy is used for men who don't naturally produce enough of the hormone for normal function. Testosterone controls the development of the male sexual organs and helps maintain essential “maleness” or secondary male sexual characteristics. Testosterone therapy is administered as a patch worn on the skin that is prescribed by your physician. It also may be administered via pill or injection.

Non-Serious Side Effects

Testosterone therapy may produce side effects that aren't serious and may fade with time and continued use of the patch, according to the Mayo Clinic. These may include weakness, dizziness, rapid growth, pain throughout the body, acne, tingling or burning sensations in the skin, insomnia, lowered libido, light-headedness, irritability, decreased appetite, bladder control problems, mood changes, a rash, difficulty with concentration, impotence, fear and coldness in the extremities such as the hands and feet.

Serious Side Effects

Some side effects from testosterone therapy are more serious, according to the Mayo Clinic. You should contact your physician immediately if you experience serious side effects. They may include problems or pain in the testes, blisters or itching in the skin where the patch is used, rapid or slow heartbeats, bloody stools, nervousness, blurry vision, pain in the bladder, pelvis or stomach, headaches, pain in the side or back, difficulty urinating or constipation. You may notice that food tastes different, or you might have a cough, fever, increased breast size, diarrhea, dysphoria, pain or blisters on the gums, depression, paranoia and nausea.

Fertility

According to Dr. Michael A. Werner, a director with M.A.Z.E. Laboratories, a fertility facility with offices in New York and New Jersey, the testes will stop producing testosterone if it is being administered into the body externally. This condition may render the male body incapable of producing sperm “either significantly or completely,” according to Werner. Men planning to have families must consider the implications before beginning testosterone replacement therapy. One solution is to deposit sperm at a sperm bank before beginning treatment, according to Werner.

Overdose

It is possible to overdose on testosterone from replacement therapy, according to the Mayo Clinic. Side effects may include temporary blindness or blurry vision, seizures, the inability to speak, slurred speech or severe weakness in the legs or arms. Seek emergency medical treatment if any of these side effects occur.