Verbatim response from ChatGPT
Short answer
- For adult men, most professional guidelines use a total testosterone cutoff of about 300 ng/dL (≈10.4 nmol/L). If your morning total testosterone is consistently below ~300 ng/dL and you have compatible symptoms, treatment is usually considered.
- Below ~200 ng/dL (≈6.9 nmol/L) is more clearly “deficient.” Levels between roughly 200–300 ng/dL are borderline and need careful clinical judgment (symptoms, repeat tests, and possibly free testosterone).
Why it isn’t just a number
- Treatment is recommended only when low lab values are combined with symptoms (reduced libido, erectile dysfunction, low energy, loss of muscle mass, depressed mood, decreased bone density, etc.). Many men with mildly low numbers and no symptoms are not treated.
- Labs vary by laboratory and assay method. Age and conditions that change sex‑hormone binding globulin (SHBG) — obesity, diabetes, thyroid disease — can make total testosterone misleading; in those cases free or bioavailable testosterone is helpful.
How to get an accurate diagnosis
- Have total testosterone measured in the morning (usually before 10 a.m.), fasting if possible.
- If low, repeat the total testosterone on a separate day to confirm.
- If results are borderline or you have factors that affect SHBG, ask for free testosterone or calculated free testosterone and SHBG.
- Also check LH and FSH (to distinguish primary vs secondary hypogonadism), and consider prolactin, TSH, and other tests as indicated.
Before starting treatment
- A clinician should evaluate for causes of low testosterone and screen for contraindications: prostate cancer (baseline PSA), polycythemia (baseline hematocrit), uncontrolled heart failure, uncontrolled severe sleep apnea, and clotting disorders.
- If started on testosterone, monitoring typically includes symptom response, testosterone levels, hematocrit, and PSA at intervals recommended by the treating clinician.
Practical numbers and conversions
- Common cutoffs: <200 ng/dL = clearly low; 200–300 ng/dL = borderline; >300 ng/dL = usually not treated unless free T is low and symptoms present.
- Conversion: ng/dL × 0.0347 ≈ nmol/L. So 300 ng/dL ≈ 10.4 nmol/L.
Treatment options (examples)
- Gels: AndroGel, Testim — steady daily dosing, easy to use but risk of transference to others.
- Injections: Testosterone cypionate or enanthate (often prescribed as Depo-Testosterone by clinicians) — less frequent dosing (weekly to every 2–3 weeks) and commonly used.
- Long‑acting injectable: Aveed — every 10–14 weeks after loading regimen (has specific administration rules).
- Nasal: Natesto — multiple daily doses, less risk of skin transfer.
- Choice depends on lifestyle, cost, side‑effect profile and monitoring needs; a clinician will help pick the best option.
Where to get testing and care
- Standard labs: Quest Diagnostics or LabCorp for blood testing.
- For clinical evaluation and treatment you can see a primary care doctor, endocrinologist, or urologist. Telemedicine men’s health services (examples: Hims, Roman/Ro, Vault Health) offer testing and treatment pathways but it’s important they do a full evaluation and arrange proper monitoring.
Next steps
- If you suspect low testosterone, make an appointment with your primary care physician or an endocrinologist/urologist. Bring symptoms you’ve noticed and ask for a morning total testosterone test (and repeat if low). If you’d like, tell me your lab value and symptoms and I can help interpret them and suggest questions to bring to your clinician.