What Causes Low Testosterone?

If you have low testosterone or suspect that you may, you are certainly not alone. In fact, a publication from the Boston University School of Medicine says as many as 4 to 5 million men are affected in the U.S. alone. In this post, we’ll explain what low testosterone all is about and what causes this condition, which you may know from advertising as “Low-T.”

What is Low Testosterone (Hypogonadism)?

Low testosterone, medically known as hypogonadism, is a condition in which the testicles do not produce enough of the male sex hormone testosterone. It is most common in older men – the Cleveland Clinic says about 40 percent of American men age 45 and older have low-T. But older men aren’t the only ones affected. Testosterone production begins to tail off by the age of 30 in most men – dropping about 1 percent a year, according to the Cleveland Clinic – and even teens can find themselves affected.

There are two types of low testosterone: primary hypogonadism and secondary hypogonadism. Let’s discuss the causes of each.

What Causes Primary Hypogonadism?

Primary hypogonadism is traced to a physical problem with the testicles. The Mayo Clinic offers up several potential issues that cause this type of low testosterone:

Cancer treatments: Powerful chemotherapy or radiation treatments can cause testosterone production to fall. In many cases, this is temporary, and testosterone can return to normal levels after the treatment.
Injured testicles: Physical damage to the testicles can cause testosterone production to drop or stop altogether.
Klinefelter syndrome: This is a condition where a male has two or more X chromosomes in addition to the one Y chromosome. Males normally have only one X to go with the one Y. The presence of more than one X chromosome can inhibit testosterone production.
Hemochromatosis: A condition where the person has too much iron in the blood, negatively affective testosterone production.
Mumps: Mumps can affect the testicles in adolescents or adults, affecting testosterone production.
Undescended testicles: Testosterone production is sometimes reduced if the testicles do not descend within the first few years of a boy’s life.

What Causes Secondary Hypogonadism?

Secondary hypogonadism is traced to a glandular issue, with either the pituitary gland or the hypothalamus. With this form of low testosterone, the testicles are normal, but the gland problem impedes testosterone production. The Mayo Clinic gives many potential causes for this, and we’ll list a few of them here:

Kallmann syndrome: This is the abnormal development of the hypothalamus itself.
Brain tumors or pituitary disorders: A tumor on the pituitary gland or parts of the brain near the gland can cause testosterone deficiencies.
Certain inflammatory diseases: Diseases that involve the hypothalamus and pituitary gland, such as tuberculosis, can lead to low testosterone.
Aging or obesity: Testosterone production drops in all men as they age, and men who are significantly overweight can be affected even more.
Medications: Opioids, some hormones, and steroids can cause low-T.