Article: Testosterone is responsible for the production of male sexual characteristics and functions, including a deep voice, facial hair, and denser bone and muscle mass. It is directly related to erectile functions, penis and testicular size, and the sex drive. Testosterone is also involved with the production of red blood cells and sperm. Normal levels of testosterone help to prevent high blood pressure and heart attacks. Low levels of testosterone may represent normal male aging; however, low levels of testosterone are also associated with a number of different health issues in men, as well as an increased risk of death. Testosterone levels vary in different men, so it can be difficult to determine if the levels detected in one man are too low or if they represent a normal decrease with age.  It is quite normal for a man’s testosterone level to decrease gradually with age. It is also quite normal to have fewer erections as a man ages. It is not normal, however, to be unable to have or sustain an erection, and it is not normal to lose interest in sex. This can be a symptom of many other, more common cases as well, including diabetes and depression. Though low testosterone is normal, levels that are too low can lead to many health problems. Symptoms of low levels of testosterone in men include:  Problems with sexual function. This can include erectile dysfunction, decreased desire for sexual activity, and a decrease in the number and quality of erections. Smaller testes Emotional problems, such as depression, irritability, anxiety, problems with memory or concentration Sleep disruption Increased fatigue or a general overall lack of energy Body changes, such as increased belly fat, decreased muscle mass, decreased strength and endurance, decreased cholesterol levels, and osteopenia (softening of the bones) and osteoporosis (decreased bone density) Swollen or tender breasts Loss of body hair Hot flashes Women can have low testosterone as well. Symptoms of low testosterone in women include decreased sexual desire and function, muscle weakness, decreased vaginal lubrication, and infertility. To diagnose low testosterone levels, your physician will perform a physical exam and take a blood sample to test for testosterone levels. Depending on your physical exam, your symptoms, and your history, other tests may be performed as well. These tests check for thyroid function, diabetes, high blood pressure, and heart disease. If you are experiencing any of the symptoms, call your physician to have your testosterone levels tested. For those individuals who do choose TRT, you should know about potential side effects. Because of these potentially serious side effects, your physician will be most likely asking you to come in frequently for checkups. This may be every three to six months. You should also keep track of any changes in your body and report them immediately to your physician. The side effects include:  Increased risk of heart attacks and heart disease Increased risk of strokes and blood clots Increased risk of prostate cancer Sleep apnea Polycythemia, or increased levels of red blood cells — this causes the blood to get thicker and increases the risk of blood clots. Enlargement of male breasts Acne and oily skin Changes in hair patterns Decrease in the size of testicles Changes in cholesterol and blood lipid levels Testosterone replacement therapy (TRT) is not for every man. There are circumstances in which it is not recommended. For example, TRT is not recommended for men with sleep apnea, a high red blood cell count, congestive heart failure, or prostate conditions, such as benign prostatic hypertrophy, prostate cancer, or breast cancer.

What is a summary?
Learn the importance of testosterone. Understand why low testosterone levels occur. Know the symptoms of low testosterone. Diagnose testosterone levels. Know the side effects of TRT. Understand when not to take testosterone.