ArticlesAll About Endocrine Hormones
Anti-Aging Hormones: Do They Work?
Male menopause is an informal term used for a condition caused when testosterone levels decrease in aging men. Experts disagree on how widespread the condition is.
Testosterone is the male sex hormone responsible for male characteristics. It triggers the penis and testicles to form in a fetus. At puberty, testosterone causes the penis and testicles to grow larger. It also causes facial and pubic hair to grow, the voice to deepen, and muscle mass and strength to increase. It governs where fat is distributed on the body and oversees the increase in body height that occurs during adolescence. Testosterone also controls sex drive and sperm production.
Testosterone is made by the testicles. A small amount also is made by the adrenal glands, located next to the kidneys. (In women, small amounts of testosterone typically are released from the ovaries and adrenal glands.)
Testosterone production is controlled by a complicated process that begins in a part of the brain called the hypothalamus. The hypothalamic region releases a hormone called gonadotropin-releasing hormone (GnRH) to the brain's pituitary gland. The pituitary gland then releases luteinizing hormone (LH), which signals the testicles to make testosterone. When there is enough testosterone, the hypothalamus sends a message to the pituitary gland to lower LH release, and the testicles slow down production of testosterone. The typical adult male generates approximately 5 to 10 mg of testosterone each day.
Testosterone production reaches its peak during adolescence and young adulthood. The range of what is considered a “normal” level of testosterone varies widely. Testosterone levels usually decline as a man ages, but never drop to zero, as estrogen does for a woman when she reaches menopause.
In young men, a testosterone level that is too low can be caused by genetic conditions such as:
Klinefelter's syndrome. A condition in which men have an extra X chromosome. Although this condition affects approximately 1 in every 500 to 700 males, many men affected by Klinefelter's syndrome are undiagnosed until adult life.
Hemochromatosis. A disorder in which too much iron is deposited in body tissues, including the pituitary gland.
Kallmann's syndrome. Patients with Kallmann's syndrome typically lack a sense of smell, beginning at birth.
Prader-Willi syndrome. A disorder in which the genitals are underdeveloped; often testes don’t descend fully.
Myotonic dystrophy or adult muscular dystrophy.
Other causes in young men include:
Trauma to the testicles
Inflammation of the testicles often caused by getting mumps after puberty
Radiation treatment or chemotherapy
Treatment of tumors of the testicles
Tumors of the pituitary gland
Medications, such as narcotic pain medications, prednisone, and anabolic steroids
HIV infection or AIDS
Aging causes a normal decrease in the production of testosterone in men. This is sometimes called andropause. As men age, testosterone production decreases by a small percentage each year.
The normal decline in testosterone because of aging causes some men's hormone levels to go down more than others. Some men have more symptoms than other men. Symptoms of low testosterone in older men can also be symptoms of many other conditions.
Talk to your health care provider if you have any of these symptoms:
Progressive decrease in muscle mass
Decreased desire or interest in sex (libido)
Erectile dysfunction (trouble attaining or maintaining an erection)
Abnormal weight gain
Feeling irritable or angry
Loss of motivation
Loss of drive at work
Problems with memory and concentration
Loss of energy
A simple blood test can determine your testosterone level. The serum total testosterone test is the most common. This test should be done in the morning, when the testicles usually release more testosterone. Normal results usually range from 300 to 1000 ng/dL (or 10 to 38 nmol/L). Treatment to replace testosterone may be needed if testosterone levels fall too low. Because a normal level of testosterone is different for each man, however, it may be hard to know if you have low testosterone with just one test; you may need several tests taken over time.
About 98 percent of the testosterone carried in the blood is bound to two proteins and is not available to the body. The remaining 2 percent, which circulates freely, causes the effects on body tissues. As men age, more testosterone is bound by proteins. Too little free testosterone can cause the symptoms listed above.
For men whose testicles produce too little or no testosterone (a condition called hypogonadism), health care providers may prescribe testosterone replacement therapy (TRT). TRT works to restore sex drive, fertility, muscle strength, and prevent bone loss. But the long-term benefits and risks of TRT in healthy, aging men have not been studied.
In the majority of short-term studies, TRT decreased a man’s fat mass, increased muscle mass, and improved strength. Because ED usually has causes other than low testosterone, TRT does not help in the majority of ED cases.
High doses of testosterone can cause sleep problems and infertility. In addition, high doses of testosterone may cause benign (noncancerous) growth of the prostate gland. This can lead to a condition called benign prostatic hyperplasia. If an undetected prostate cancer is present, experts worry that TRT could cause rapid growth of the cancer. TRT should not be started in patients with a history of breast or prostate cancer. A licensed medical provider should perform a thorough evaluation on anyone with a high risk for these cancers, before TRT is started. Other contraindications for TRT exist. Men considering TRT should talk to their licensed medical provider to see if they are good candidates for this treatment.
TRT can be given by injections every two to three weeks; by daily skin patches or topical gel; or by implanted pellets that are inserted every four to six months. A recently approved form of testosterone is administered by tablet and placed under the tongue or beside the gum. Testosterone is not given routinely and can cause certain side effects. Men should discuss the risks and benefits of treatment on an individual basis with a heath care professional prior to treatment.