What Testosterone, Total tells you.Total testosterone measures the sum of protein‑bound and free testosterone circulating in blood. It reflects how much androgen your body is making and carrying, which influences cellular energy use, muscle and bone building, red blood cell formation, fat distribution, libido and fertility, mood and cognition, and cardiometabolic signaling.Low values usually reflect reduced production or increased binding that lowers bioavailable hormone. In men, this can follow testicular or pituitary dysfunction, chronic illness, higher adiposity and inflammation, or certain medications, and often shows up as lower energy, decreased muscle, more fat, anemia, lower libido/erectile issues, depressed mood, and reduced bone density (hypogonadism). In women, very low levels can accompany adrenal or ovarian insufficiency and may relate to low sexual desire, reduced vitality, and lower bone turnover, though many women feel well at low‑normal levels.Being in range suggests androgen signaling is adequate for stable energy, healthy body composition, hematopoiesis, bone maintenance, and reproductive function. In adult men, symptom‑free status often aligns with mid‑to‑upper portions of the reference range; in women, typical healthy levels sit toward the lower end of the range.High values usually reflect increased production or reduced negative feedback. In men, this is seen with exogenous androgens or androgen‑secreting tumors and can drive acne, oily skin, mood changes, elevated red blood cells, adverse lipids, hypertension, and infertility. In women, high values point to hyperandrogenism (e.g., PCOS, adrenal/ovarian tumors, congenital adrenal hyperplasia) with hirsutism, acne, ovulatory dysfunction, and increased metabolic risk.Notes: Levels peak in the morning and decline with age. Acute illness suppresses values. Sex hormone–binding globulin (SHBG) strongly alters total versus free; estrogens (pregnancy, oral estrogens) raise SHBG and lower free. Assay method matters—mass spectrometry is more reliable at low concentrations.