Can low testosterone cause problems?

Health Impacts of Low Testosterone in Men

Low testosterone can cause significant health problems including diminished libido, erectile dysfunction, decreased vitality, reduced muscle mass, increased adiposity, depression, anemia, osteopenia, and osteoporosis, which can substantially impact morbidity, mortality, and quality of life. 1

Clinical Definition and Prevalence

Hypogonadism (low testosterone) is defined as a clinical condition characterized by low serum testosterone levels occurring in association with specific signs and symptoms. The normal testosterone range for adult men is typically 300-800 ng/dL in most laboratories 1. Hypogonadism affects an estimated 2-4 million men in the United States, with prevalence increasing with age, yet only about 5% of affected men receive treatment 1.

Health Consequences of Low Testosterone

Physical Health Impacts

• Musculoskeletal effects: Decreased muscle mass and strength, reduced bone density leading to osteoporosis 1
• Body composition changes: Increased adiposity, particularly visceral fat, which contributes to metabolic dysfunction 1, 2
• Cardiovascular implications: Multiple epidemiologic studies have associated low testosterone levels with increased all-cause and cardiovascular mortality 1
• Metabolic effects: Insulin resistance, type 2 diabetes mellitus, and metabolic syndrome 1, 2
• Anemia: Reduced red blood cell production 1

Mental and Sexual Health Impacts

• Sexual dysfunction: Diminished libido and erectile quality, particularly nocturnal erections 1, 2
• Psychological effects: Depressed mood, decreased intellectual activity, fatigue, anger, and reduced sense of well-being 1, 2
• Cognitive changes: Decreased spatial orientation and cognitive function 2

Diagnosis of Low Testosterone

The Endocrine Society recommends measuring morning total testosterone levels in men with symptoms of hypogonadism 1, 3. Diagnosis should include:

• Morning testosterone measurements (between 8-10 AM) when levels are highest 1
• At least two separate testosterone measurements to confirm the diagnosis 3
• Assessment of both total and free testosterone levels, particularly in men with obesity where sex hormone-binding globulin (SHBG) may be altered 1
• Additional testing of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) to distinguish between primary and secondary hypogonadism 1, 3

Relationship with Other Health Conditions

Low testosterone is strongly associated with several chronic conditions:

• Metabolic syndrome: Central obesity, insulin resistance, dyslipidemia, and hypertension 2
• Type 2 diabetes: Testosterone deficiency is common in men with diabetes 1, 2
• Obesity: Increased aromatization of testosterone to estradiol in adipose tissue can suppress testosterone production 1
• Cardiovascular disease: Low testosterone is associated with increased atherosclerosis and cardiovascular risk 1, 2
• Erectile dysfunction: Low testosterone is a common cause of erectile dysfunction and reduced response to PDE5 inhibitors 1

Treatment Considerations

For men with symptomatic hypogonadism, testosterone replacement therapy (TRT) may provide benefits including:

• Improved sexual function and libido 1
• Increased bone mineral density 1
• Improved body composition (increased lean mass, decreased fat mass) 1
• Enhanced mood and sense of well-being 1
• Improved insulin sensitivity and glycemic control in men with diabetes or metabolic syndrome 1

Important Caveats

1. Diagnostic challenges: Testosterone levels can be affected by acute illness, medications, time of day, and laboratory methods 4
2. Treatment risks: Potential side effects of testosterone therapy include erythrocytosis, fluid retention, and concerns about prostate health 1, 5
3. Fertility implications: Testosterone therapy can suppress spermatogenesis and should be avoided in men seeking fertility 5
4. Age-related considerations: The benefits and risks of testosterone therapy may differ across age groups, with older men potentially at higher risk for adverse effects 6
5. Causality question: It remains uncertain whether reduced testosterone is a cause of ill-health or a marker of pre-existing disease, as systemic illness can lower testosterone levels 6

Clinical Approach

1. Screen for symptoms of hypogonadism in men, particularly those over 40
2. Measure morning total testosterone levels in symptomatic men
3. If testosterone is low (typically <300 ng/dL), confirm with repeat testing
4. Assess free testosterone in men with borderline total testosterone (8-12 nmol/L or approximately 230-350 ng/dL) 4
5. Evaluate for underlying causes of hypogonadism
6. Consider testosterone replacement therapy in men with confirmed symptomatic hypogonadism after discussing potential benefits and risks

Low testosterone is a significant health concern that can substantially impact multiple body systems and overall quality of life. Proper diagnosis and management are essential to improve outcomes in affected men.