Low Testosterone Health Risks: What the Evidence Shows

By Noophoric Editorial Team Updated August 31, 2026

Low testosterone can affect sexual function, fertility, bone, muscle, red blood cell production, and quality of life. However, a low result is not a diagnosis by itself. Symptoms must be considered alongside at least two accurate early-morning blood tests, and the cause matters.

Testosterone naturally varies by time of day, illness, sleep, calorie intake, medications, and body weight. Some men have temporary or reversible reductions. Others have hypogonadism caused by a problem involving the testes, pituitary gland, or hypothalamus. Those situations do not carry the same risks or require the same treatment.

What counts as low testosterone?

The Endocrine Society recommends diagnosing hypogonadism only when a man has compatible symptoms and consistently low testosterone measured with reliable testing. A single afternoon result, a home symptom quiz, or fatigue alone is not enough. The Society's 2026 statement recommends at least two early-morning, fasting tests and notes that a threshold near 300 ng/dL is commonly used, although laboratories and clinical circumstances differ.

If a first result is low, a clinician may repeat total testosterone and consider free testosterone, sex hormone-binding globulin, luteinizing hormone, prolactin, thyroid testing, iron studies, or other evaluation based on the history. Our guide to testosterone testing explains the process in more detail.

Possible health effects of confirmed hypogonadism

Sexual function and fertility

Reduced libido, fewer spontaneous erections, and erectile difficulties can occur with testosterone deficiency. These symptoms are not specific, so cardiovascular disease, diabetes, medication effects, relationship factors, sleep problems, and depression also deserve attention. Testosterone is also involved in sperm production, but taking testosterone from outside the body can suppress sperm production. Men who want children should not start testosterone without discussing fertility first.

Bone health

Long-standing testosterone deficiency can reduce bone mineral density and increase fracture risk. This is one reason clinicians may consider bone-density testing in men with significant or prolonged hypogonadism, especially when other osteoporosis risks are present. Bone health also depends on resistance exercise, calcium and vitamin D status, smoking, alcohol use, age, and medications.

Muscle and body composition

Testosterone supports muscle protein synthesis and helps maintain lean mass. Men with clinically significant deficiency may notice reduced strength or muscle mass and increased body fat. These changes are not proof of low testosterone because inactivity, under-eating protein, aging, chronic disease, and poor sleep can produce similar effects.

Red blood cells and energy

Testosterone helps stimulate red blood cell production. Deficiency can contribute to anemia in some men, which may worsen fatigue or exercise tolerance. Fatigue is still one of the least specific symptoms. Sleep apnea, anemia from other causes, thyroid disease, depression, infection, and medication effects are common alternatives that should not be overlooked.

Mood and cognition

Some men with hypogonadism report low mood, irritability, or difficulty concentrating, but these symptoms have many causes and studies do not support using them alone to diagnose testosterone deficiency. See our evidence review on low testosterone and depression for a more focused discussion.

Does low testosterone cause heart disease?

Low testosterone is associated with obesity, type 2 diabetes, and cardiovascular disease in observational studies. Association does not prove that low testosterone directly causes those conditions. Chronic illness and excess body fat can lower testosterone, so the relationship can work in both directions.

The large TRAVERSE trial helped clarify short-term cardiovascular safety of prescribed testosterone in appropriately selected men, but it did not prove that testosterone prevents heart disease. The Endocrine Society's 2026 statement notes that myocardial infarction and stroke were not meaningfully increased over one to four years, while pulmonary embolism and fractures occurred more often and long-term safety remains uncertain.

What to do if you are concerned

Write down specific symptoms, when they started, and any medication or health changes.
Ask for properly timed repeat testing rather than relying on one value.
Address reversible contributors such as obesity, sleep apnea, severe calorie restriction, heavy alcohol use, and certain medications with a clinician.
Discuss fertility goals before any hormone treatment.
Do not use an over-the-counter booster as a substitute for diagnosis.

Weight loss is the preferred first-line approach for obesity-related functional low testosterone because it can improve hormone levels and overall health without exposing a man to unnecessary hormone therapy.

Bottom line

Confirmed hypogonadism can affect sexual function, fertility, bone, muscle, blood production, and well-being. The safest next step is accurate diagnosis and evaluation of the cause. A single low number or a vague symptom list should not lead directly to testosterone therapy or a supplement.

Sources

Evidence reviewed August 2026. This article is educational and is not a substitute for individualized medical diagnosis or treatment.