context: Testosterone is a hormone produced by the testicles and is responsible for the proper development of male sexual characteristics. Testosterone is also important for maintaining muscle bulk, adequate levels of red blood cells, bone growth, a sense of well-being, and sexual function. var s_context; s_context= s_context || {}; s_context['wb.modimp'] = 'vidfloat'; if(webmd.useragent && webmd.useragent.ua.type === 'desktop'){ webmd.ads2.disable Initial Load(); webmd.ads2.disable Ads Init = true; $(function() { webmd.p.pim.increment(); $('.responsive-video-container').insert After('.module-social-share-container'); require(['video2/1/responsive-player/video-loader'], function(video Loader) { video Loader.init({ autoplay: webmd.useragent.ua.type === 'desktop' && ! !s_sensitive, chron ID: $('article embeded_module[type=video][align=top]:eq(0)').attr('chronic_id'), continuous Play: true, cp Options: { flyout: true }, display Ads: true, mode: 'in-article', sticky: true }) }); }); } else { $(function(){ $('.responsive-video-container').remove(); }); } Inadequate production of testosterone is not a common cause of erectile dysfunction; however, when ED does occur due to decreased testosterone production, testosterone replacement therapy may improve the problem. As a man ages, the amount of testosterone in his body naturally gradually declines. This decline starts after age 30 and continues throughout life. Some causes of low testosterone levels are due to: Injury, infection, or loss of the testicles Chemotherapy or radiation treatment for cancer Genetic abnormalities such as Klinefelter's Syndrome (extra X chromosome) Hemochromatosis (too much iron in the body) Dysfunction of the pituitary gland (a gland in the brain that produces many important hormones) or hypothalamus Inflammatory diseases such as sarcoidosis (a condition that causes inflammation of the lungs) Medications, especially hormones used to treat prostate cancer and corticosteroid drugs Chronic illness Chronic kidney failure Cirrhosis of the liver Stress Alcoholism Obesity (especially abdominal) Without adequate testosterone, a man may lose his sex drive, experience erectile dysfunction, feel depressed, have a decreased sense of well-being, and have difficulty concentrating. Low testosterone can cause the following physical changes: Decrease in muscle mass, with an increase in body fat Changes in cholesterol levels Decrease in hemoglobin and possibly mild anemia Fragile bones (osteoporosis) Decrease in body hair Changes in cholesterol and lipid levels The only accurate way to detect the condition is to have your doctor measure the amount of testosterone in your blood. Because testosterone levels fluctuate throughout the day, several measurements will need to be taken to detect a deficiency. Doctors prefer, if possible, to test levels early in the morning, when testosterone levels are highest. Note: Testosterone should only be used by men who have clinical signs and symptoms AND medically documented low testosterone levels. Testosterone deficiency can be treated by: Intramuscular injections, given anywhere from two to 10 weeks apart Testosterone gel applied to the skin or inside the nose Mucoadhesive material applied above the teeth twice a day Long-acting subcutaneous pellet Testosterone stick (apply like underarm deodorant) Each of these options provides adequate levels of hormone replacement; however, they all have different advantages and disadvantages. Talk to your doctor to see which approach is right for you. Men who have prostate cancer or breast cancer should not take testosterone replacement therapy. Nor should men who have severe urinary tract problems, untreated severe sleep apnea or uncontrolled heart failure. All men considering testosterone replacement therapy should undergo a thorough prostate cancer screening -- a rectal exam and PSA test -- prior to starting this therapy. In general, testosterone replacement therapy is safe. It is associated with some side effects, including: Acne or oily skin Mild fluid retention Stimulation of prostate tissue, with perhaps some increased urination symptoms such as a decreased stream or frequency Increased risk of developing prostate abnormalities Breast enlargement Increased risk of blood clots Worsening of sleep apnea (a sleep disorder that results in frequent night time awakenings and daytime sleepiness) Decreased testicular size Increased aggression and mood swings May increase risk of heart attack and stroke Laboratory abnormalities that can occur with hormone replacement include: Changes in cholesterol and lipid levels Increase in red blood cell count Decrease in sperm count, producing infertility (especially in younger men) Increase in PSA If you are taking hormone replacement therapy, regular follow-up appointments with your doctor are important. Like any other medication, directions for administering testosterone should be followed exactly as your doctor orders. If you are unsure or have any questions about testosterone replacement therapy, ask your doctor.