Low testosterone in men is most often caused by a combination of testicular, pituitary, and systemic factors. Below is a concise overview of the main categories and common contributors. What it is
- Testosterone deficiency (male hypogonadism) occurs when the body doesn’t produce enough testosterone or the tissues don’t respond properly to it. This can be due to problems with the testicles themselves (primary hypogonadism) or with the signals the brain and pituitary gland send to the testes (secondary hypogonadism).
Common causes
- Primary testicular problems (originating in the testes)
- Injury or infection of the testes (trauma, mumps orchitis)
* Genetic conditions such as Klinefelter syndrome or other congenital abnormalities
* Cancer treatments like chemotherapy or radiation that damage testicular tissue
* Long-standing systemic illnesses or metabolic disorders that affect testicular function (e.g., hemochromatosis)
* Aging, which is associated with gradual declines in testosterone production in many men
* Obesity and metabolic syndrome can impact testosterone production and metabolism
- Secondary (central) causes (originating in the brain/pituitary)
- Pituitary gland disorders or tumors that reduce signaling to the testes
* Hormone deficiencies or imbalances affecting the hypothalamic-pituitary-testicular axis
* Certain medications and medical treatments that affect hormone signaling (e.g., opioids, long-term corticosteroids, prostate cancer therapies)
- Other contributing factors and conditions
- Chronic diseases such as diabetes, liver disease (cirrhosis), kidney disease, or HIV/AIDS
* Obstructive sleep apnea and poor overall nutrition or malnutrition can be associated with lower testosterone
* Excess estrogen levels or other hormonal imbalances that disrupt the normal testosterone balance
* Alcohol abuse or substance misuse and certain medications (antidepressants, narcotics) can lower testosterone
* Hypothyroidism or other endocrine disorders can contribute to low testosterone levels
Key notes
- Not all men with these risk factors will have low testosterone, and symptoms can vary widely even with similar testosterone levels.
- Symptoms to watch for include reduced libido, erectile difficulties, fatigue, decreased muscle mass and strength, increased body fat, mood changes, and reduced bone density. If suspected, testing usually includes morning total testosterone levels, sometimes free testosterone and SHBG, plus evaluation for underlying causes.
What to do if concerned
- If experiencing possible symptoms or risk factors, consult a healthcare provider for an evaluation. They may check your hormone levels, review medications, assess overall health, and look for treatable underlying causes (e.g., pituitary issues, thyroid problems, diabetes control, obesity).
- Treatments depend on the cause and may include addressing the underlying condition, lifestyle changes (weight management, exercise, sleep), and, in select cases, testosterone replacement therapy after careful discussion of benefits and risks with a clinician.
If you’d like, specify your age, symptoms, and any known medical conditions or medications, and I can tailor this overview to your situation and suggest potential next steps.
