Lab marker

Total Testosterone

Testosterone is the primary male sex hormone (and a smaller-quantity hormone in women). Low values in men cause fatigue, low libido and infertility; high values in women often signal PCOS.

Common unit ng/dL
Adult reference range 300–1000 ng/dL (adult males morning); 15–70 (adult females)

What it measures

Total testosterone is the sum of free testosterone, SHBG-bound and albumin-bound fractions. In men it is the principal androgen — driving libido, muscle mass, bone density, sperm production and mood. The standard draw is morning (08:00–10:00), fasting, on at least two occasions before diagnosing hypogonadism, because levels swing diurnally and acutely with illness. In women testosterone is produced in smaller quantities by ovaries and adrenals; elevation is the usual concern (PCOS, adrenal pathology).

What a high value can mean

  • In women: PCOS — most common; usually with elevated free androgen index, irregular periods, acne, hirsutism.
  • Congenital adrenal hyperplasia, androgen-secreting tumour — rarer.
  • Anabolic steroid use, testosterone replacement overdose — exogenous source.
  • In men: rarely a concern in routine practice; very high points to exogenous use or testicular tumour.

What a low value can mean

  • Male hypogonadism — primary (testicular) — Klinefelter, post-orchitis, chemotherapy.
  • Male hypogonadism — secondary (pituitary) — pituitary tumour, opioid use, severe obesity, sleep apnoea, chronic illness.
  • Age-related decline — modest, gradual; not all symptoms in older men respond to replacement.
  • Stress, acute illness, recent intense exercise — transient drops.

When to discuss with a doctor

In a man with persistent symptoms (low libido, fatigue, erectile dysfunction) and morning total testosterone <300 ng/dL on two occasions, an endocrinology / urology consultation is appropriate to decide on replacement vs investigating the cause. In a woman with elevated testosterone plus irregular cycles or hirsutism, a PCOS work-up is the usual next step. Mediora.AI surfaces the threshold; replacement therapy belongs with a physician.

Related markers

See your own lab result explained marker-by-marker Upload a PDF or photo. Free during the open beta. Doctor-reviewed.
Upload →