Identifying and treating hypogonadism
Most people think of testosterone as the male hormone, because men typically have much higher levels of the hormone than women.1 However, as men age, their testosterone levels begin to decline. This process can be a normal part of getting older, but it may also be the result of a medical condition called hypogonadism or andropause.
Low testosterone levels are more than just an inconvenience. Hypogonadism can cause sexual dysfunction and lead to health problems, such as osteoporosis and depression.
Low serum testosterone levels affect approximately 40% of men aged older than 45 years, and more men develop the condition as they age -- approximately half of men aged 80 years and older have low testosterone,2 according to the American Urological Association. The first step in recommending treatment options for patients with low testosterone is properly identifying the condition.
Slow changes to the body, including reduced body hair and decreased prostate size are symptoms of low testosterone, according to the American Association of Clinical Endocrinologist's (AACE) medical guidelines for evaluating and treating hypogonadism.
In other men, low testosterone levels may prevent hair loss. Infertility is also associated with the condition; therefore, it is not uncommon to make the diagnosis during an infertility workup.3
Two main areas of the body affect testosterone levels: the testicles, and the pituitary gland and nearby hypothalamus.4 The testicles actually produce testosterone, whereas the hypothalamus and pituitary gland send chemical signals to regulate production.
Low testosterone levels can result from a problem in either region. Low testosterone that originates in the testicles is called primary hypogonadism, whereas those cases caused by a malfunctioning pituitary gland or hypothalamus are referred to as secondary hypogonadism.
Men may inherit a trait that causes problems with testosterone production, or the condition may be triggered by an infection or injury.
Common causes of primary hypogonadism are:
- Testicular injury
- A mumps orchitis infection affecting the testicles
- Undescended testicles
- Radiation or chemotherapy
Secondary hypogonadism may result from:
- Abnormal hypothalamic development due to Kallmann syndrome
- A pituitary tumor or disorder
- Sarcoidosis, tuberculosis or another inflammatory disease
- HIV or AIDS
- Opiate use
In addition to the above risk factors, men with type 2 diabetes have twice the risk of hypogonadism than the average man.5
In some cases, low testosterone might be a normal side effect of aging. Clinicians have differing opinions about what testosterone levels should prompt intervention.4
When a man's testosterone levels are too low, it affects not only his sex drive and sperm function but may also have implications for bone health, red blood cell production and the development and distribution of muscle and fat.4
Common side effects associated with low testosterone include:6
- Depressed mood
- Reduced strength
- Cognitive problems
- Hot flashes
Making the diagnosis
Once physical symptoms of low testosterone are identified, labs to measure total testosterone levels should be performed to confirm the diagnosis. The AACE defines the normal range for testosterone as between 300 to 1,000 ng/dL. Anything below that range is considered low. Blood tests should be performed in the morning, when testosterone levels are typically highest.3
Once hypogonadism is diagnosed, the clinician must then identify whether the disorder is primary or secondary using additional labs, such as hormone tests, semen analysis, genetic studies and examinations of the pituitary gland and testicles.
Recommendations for treating low testosterone vary and are somewhat controversial. Patients undergoing treatment should be monitored to ensure appropriate care and that all possible side effects and related reactions are adequately managed.
Men with confirmed low testosterone who choose to undergo treatment have a number of options, including testosterone replacement therapy. Studies show that testosterone replacement therapy can help rebuild muscle, restore sexual function and prevent osteoporosis.6
Today, testosterone replacement is being used more than in the past. Between 1993 and 2001, testosterone sales jumped 500%, according to the AAFP.6 Although initial studies by the National Institutes of Health did not find any major adverse effects from testosterone therapy, additional government studies are ongoing. Side effects include acne and polycythemia.7,8
There are many different types of hormone replacement. Delivery options include injections, patches, gels or pills.4 Each option has distinct advantages, disadvantages, varying side effects and costs:
Injections. A clinician, patient or family member must administer an intramuscular injection once every two weeks. A disadvantage is that symptoms may start to return as the dose wears off.
Patch. The patient can apply a sticky patch to his back, thigh, upper arm or stomach and must switch out the patch each day. If the patch is not rotated between body parts it may irritate the skin.
Gel. The patient can apply testosterone gel to the lower abdomen, upper arm or shoulder. As the gel dries, the testosterone is absorbed through the skin. Studies show gel is less irritating to the skin than the patch, but patients should be advised not to wash for several hours after applying and to avoid contact with their partners.
Oral patch. Another option lets patients use a sticky patch designed to adhere to the area above their top teeth. The patch includes gel that is activated when it comes into contact with saliva, allowing the testosterone to find its way into the bloodstream.
Oral pill. Taking a testosterone pill is only suitable for short-term use, due to increased risk for liver dysfunction, high cholesterol and cardiovascular disease.
In cases of secondary hypogonadism, patients may be treated with pituitary hormones to stimulate sperm production.4 If a pituitary tumor is implicated, the patient may need surgery, radiation and hormone replacement.
But not all men are candidates for testosterone replacement, according to the AACE guidelines.3 Before prescribing this treatment, clinicians should rule out prostate cancer, breast cancer or untreated prolactinoma, as testosterone therapy can speed tumor growth in patients with these conditions.
Hormone replacement is also contraindicated in patients with high prostate specific antigen (PSA) levels, sleep apnea and those trying to conceive.
Patients who receive testosterone treatment need to have their condition monitored on a regular basis.3 Clinicians should check how well the patient is responding to treatment every three to four months during the first year.
Depending on the delivery method used, clinicians may also need to monitor testosterone levels. Although there is no conclusive link between testosterone use and prostate cancer, the AACE notes an anecdotal connection between the two. Because of this, clinicians should perform prostate examinations and PSA testing every six to 12 months in patients receiving hormone therapy and monitor hemocrit and cholesterol levels.3
Men with hypogonadism often experience mood disorders, such as depression. Clinicians should refer these patients for mental health services when necessary.3
Kelly Bilodeau is a freelance medical writer.
- National Institutes of Health. “Testosterone.” Medline Plus. Last updated: March 2012.
- American Urological Foundation. “Hypogonadism.” Last updated: January 2011.
- American Academy of Clinical Endocrinologists. American Association of Clinical Endocrinologists medical guidelines for clinical practice for the evaluation and treatment of hypogonadism in adult male patients – 2002 update.
- Mayo Clinic. “Male hypogonadism.”
- American Diabetes Association. “Low testosterone.”
- Margo K, Winn R. “Testosterone treatments: why, when, and how?” Am Fam Physician. 2006 May 1;73(9):1591-1598.
- Mayo Clinic. “Testosterone therapy: key to male vitality?” Last updated: April 2012.
- Mayo Clinic. “Polycythemia vera.” Last updated: April 2011.