What causes elevated testosterone levels in men?

Causes of High Testosterone in Men

The most common causes of elevated testosterone levels in men include anabolic steroid use, testosterone replacement therapy, certain medical conditions like congenital adrenal hyperplasia, and rare testicular tumors.

Primary Causes

Exogenous Sources

• Anabolic steroid use: Athletes and bodybuilders often take supraphysiologic doses of testosterone to increase muscle size and strength 1
• Testosterone replacement therapy: Excessive dosing or improper monitoring during treatment for hypogonadism can lead to elevated levels 2
• Performance-enhancing substances: Used in competitive sports to enhance athletic performance 3

Endogenous Causes

• Congenital adrenal hyperplasia: A group of inherited disorders affecting the adrenal glands that can cause increased androgen production 2
• Testicular tumors: Rare tumors that can secrete excess testosterone
• Adrenal tumors: Can occasionally produce excess androgens
• Genetic disorders: Certain genetic conditions affecting hormone production

Clinical Significance of Elevated Testosterone

Interestingly, elevated endogenous testosterone levels (>800 ng/dL) are not commonly associated with significant clinical morbidity. Recent research shows that only about 4% of men have naturally elevated testosterone levels above this threshold 4.

Potential Effects of High Testosterone

• Increased hematocrit: Men with elevated testosterone show higher hematocrit levels, though not typically clinically significant 4
• Elevated liver enzymes: Higher AST and ALT levels have been observed 4
• Minimal impact on other systems: No significant association with sleep disorders, urinary symptoms, or depression 4

Monitoring and Assessment

When elevated testosterone is suspected:

1. Confirm with accurate testing: Morning total testosterone levels should be measured using reliable assays 5
2. Repeat testing: Testosterone levels should be confirmed with repeat testing due to natural fluctuations
3. Additional testing: Consider measuring free testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) to determine the cause
4. Monitor for complications: Check hematocrit/hemoglobin and liver function tests 2

Complications of Supraphysiologic Testosterone

When testosterone levels are significantly elevated (particularly from exogenous sources):

• Erythrocytosis: One of the most common complications, particularly with injectable testosterone 2
• Potential cardiovascular effects: Though evidence is mixed regarding endogenous high testosterone and cardiovascular risk
• Suppression of natural production: Exogenous testosterone can suppress the hypothalamic-pituitary-testicular axis
• Testicular atrophy: Common with exogenous testosterone use 2
• Infertility: Suppression of spermatogenesis 2

Differential Diagnosis

When evaluating high testosterone:

• Rule out laboratory error: Confirm with repeat testing
• Medication review: Check for testosterone supplements, anabolic steroids, or other medications
• Evaluate for medical conditions: Consider adrenal disorders, testicular tumors
• Assess timing of sample: Testosterone levels are highest in the morning

Clinical Approach

1. Confirm elevated levels: Repeat morning testosterone measurement
2. Evaluate symptoms: Assess for signs of androgen excess (acne, increased body hair, aggressive behavior)
3. Determine source: Differentiate between exogenous and endogenous causes
4. Monitor for complications: Check hematocrit, liver function, and lipid profile
5. Treat underlying cause: Address any medical conditions or adjust medication dosing

Common Pitfalls

• Misinterpreting single measurements: Testosterone levels fluctuate naturally throughout the day
• Overlooking medication use: Always thoroughly review all supplements and medications
• Ignoring laboratory variability: Different assays may produce different results 5
• Focusing only on total testosterone: Free testosterone levels may provide additional diagnostic information

Remember that while elevated testosterone from exogenous sources can cause complications, naturally elevated endogenous testosterone appears to have minimal clinical impact in most men 4.