Verbatim response from ChatGPT
Short answer: You generally need both symptoms of testosterone deficiency and consistently low morning total testosterone on blood tests to consider treatment. Most guidelines use a total testosterone threshold of about 300 ng/dL (10.4 nmol/L) as the cutoff — i.e., symptomatic men with total T consistently below ~300 ng/dL on two separate morning tests are candidates for testosterone replacement therapy (TRT).
Details and practical steps
- When to test: Measure total testosterone in the morning (usually 7–10 AM), fasting if possible, because levels have a diurnal peak. If the first test is low or borderline, repeat it on a different morning to confirm.
- Numeric thresholds:
- Total testosterone: <300 ng/dL (10.4 nmol/L) on two separate morning samples + typical symptoms (low libido, erectile dysfunction, fatigue, low muscle mass, decreased bone density, depressed mood) → generally meets criteria to consider treatment.
- Borderline range (about 200–350 ng/dL): interpret in context of symptoms, calculate or measure free testosterone, check SHBG, and re-evaluate. Men <200 ng/dL are more likely to have clinically significant hypogonadism.
- Free testosterone: assays and reference ranges vary by lab. If total is borderline, a low calculated free testosterone (below the lab’s reference range) supports the diagnosis.
- Additional tests to order: LH and FSH (to distinguish primary vs secondary hypogonadism), prolactin if LH/FSH are low, SHBG, CBC, PSA (in older men), and metabolic/BP/lipid evaluation as appropriate.
- Contraindications/precautions: untreated prostate or breast cancer, hematocrit >50%, uncontrolled heart failure; TRT can impair fertility (spermatogenesis) — discuss sperm preservation if future fertility is desired.
- Monitoring if you start TRT: testosterone level (to target mid-normal range), hematocrit/hemoglobin, PSA, symptoms, and periodic metabolic checks. Frequency per your clinician’s plan.
Who should manage this and next steps
- See your primary care doctor, urologist, or endocrinologist if you have symptoms. Bring morning lab results or ask them to order two morning total testosterone tests plus LH/FSH and SHBG as needed.
- If you’re concerned about fertility, see a reproductive specialist before starting TRT.
If you’d like, tell me your morning total testosterone value and symptoms (and the units: ng/dL or nmol/L) and I can help interpret the result and suggest what to test next.