What testosterone level is low enough to need treatment?

Short answer

• Most guidelines say treatment is considered when total testosterone is below about 300 ng/dL (10.4 nmol/L) on at least two morning measurements and the man has consistent symptoms of testosterone deficiency (low libido, erectile problems, low energy, loss of muscle/bone mass, depressed mood, etc.).
• Levels <200–250 ng/dL (6.9–8.7 nmol/L) are more clearly deficient and more likely to benefit from therapy.

Important details and how clinicians decide

• Use total testosterone as the first test. Draw samples in the morning (usually 7–10 AM), fasting if possible. Because testosterone varies day-to-day, most clinicians require two separate low morning values before diagnosing hypogonadism.
• If total testosterone is borderline (for example ~230–350 ng/dL) or if SHBG is suspected to be abnormal (elderly, obesity, thyroid disease, liver disease), measure free testosterone (or calculate it using SHBG) — lab reference ranges vary, so interpret using the lab’s reported normal range.
• Symptoms are required. Low lab values alone do not automatically mean treat; symptoms plus low labs guide treatment decisions.

Workup and safety checks before starting testosterone

• Measure LH (to distinguish primary vs secondary hypogonadism) and prolactin (if LH is low or suspected pituitary disease).
• Baseline PSA and digital rectal exam as clinically indicated (esp. men ≥40), baseline hematocrit (testosterone can raise hematocrit), and periodic monitoring thereafter. Discuss fertility: exogenous testosterone suppresses sperm production — don’t start if you want to father children without discussing alternatives (hCG, clomiphene) with a specialist.

Which guidance is this based on

• These thresholds come from major societies (Endocrine Society, American Urological Association) that use ~300 ng/dL as the lower reference limit and recommend treating symptomatic men with confirmed low testosterone.

Practical next steps

• If you have symptoms, get a morning total testosterone measured and, if low, repeat the test. Ask your clinician to check LH and prolactin and baseline PSA/hematocrit. If you’re considering treatment, see an endocrinologist or urologist experienced with testosterone therapy to review risks and options.

If you want, tell me your last lab value (with units) and symptoms and I can help interpret it and suggest what tests to ask your clinician for.