Low Testosterone
Low testosterone (male hypogonadism) requires both symptoms and confirmed low levels, diagnosed per the Endocrine Society Clinical Practice Guideline and the American Urological Association (AUA) guideline.
Symptoms
Reduced libido, erectile dysfunction, decreased energy, depressed mood, reduced muscle mass and strength, and increased body fat; sexual symptoms (especially reduced desire) are the most specific to low testosterone itself.
Causes and risk
Aging, obesity, chronic illness, certain medications, and pituitary or testicular disorders can all lower testosterone; obesity-related low testosterone is often reversible with weight loss.
How it is evaluated
Diagnosis requires two separate early-morning (7-10am) fasting total testosterone measurements below 300 ng/dL, alongside symptoms, per both the Endocrine Society and AUA guidelines. Neither guideline recommends diagnosing based on symptom questionnaires or salivary/at-home testing alone.
Treatment
Testosterone replacement therapy is used once diagnosis is confirmed and reversible causes (obesity, certain medications) have been addressed; ongoing monitoring includes testosterone levels, hematocrit, and PSA.
When to seek care
A hematocrit above 54% while on testosterone therapy requires prompt medical attention, since it raises blood clot risk. New chest pain, leg swelling, or shortness of breath while on testosterone therapy needs urgent evaluation.