What do low testosterone levels mean?

Testosterone is the primary male sex hormone, but it plays important roles in both men and women. When a blood test flags your testosterone as high or low, it is natural to wonder what it means for your health. Testosterone influences muscle mass, bone density, fat distribution, red blood cell production, mood, and libido.

This guide explains what testosterone does, how to read your result against sex-specific reference ranges, the most common causes of abnormal levels, associated symptoms, and when to talk to your doctor. It is educational content, not a medical diagnosis—always discuss your results with a healthcare professional.

Testosterone is an androgen hormone produced mainly by the Leydig cells in the testes in men and in smaller amounts by the ovaries and adrenal glands in women. Its production is regulated by the hypothalamic-pituitary-gonadal (HPG) axis: the hypothalamus releases GnRH, stimulating the pituitary to secrete LH (luteinising hormone) and FSH (follicle-stimulating hormone), which in turn stimulate testosterone synthesis. Testosterone feeds back to suppress GnRH and LH, maintaining hormonal balance.

In men, testosterone drives the development of male secondary sexual characteristics during puberty (voice deepening, facial hair, muscle growth), supports spermatogenesis, and maintains bone and muscle mass throughout adulthood. In women, testosterone contributes to libido, bone strength, and overall energy levels, but elevated levels can cause unwanted effects like hirsutism and acne.

Most circulating testosterone is bound to SHBG (sex hormone-binding globulin) and albumin. Only about 1–3% circulates as free testosterone, the biologically active form. Your doctor may order both total and free testosterone to get a complete picture, especially if SHBG levels are suspected to be abnormal.

Testosterone levels vary by sex, age, and time of day (levels peak in the morning). Blood is typically drawn in the morning (before 10 AM) for the most reliable measurement.

Testosterone declines gradually with age in men—roughly 1–2% per year after age 30. A value near the lower end of the range in an older man may not be abnormal. In women, levels are much lower and fluctuate with the menstrual cycle. Always compare your result to the specific range on your laboratory report.

Low testosterone in men (male hypogonadism) can be classified as primary (testicular failure) or secondary (hypothalamic-pituitary dysfunction). Common causes include aging, obesity (excess fat tissue converts testosterone to estrogen via aromatase), type 2 diabetes, pituitary disorders (adenomas, hypopituitarism), chronic illness (liver disease, HIV, chronic kidney disease), Klinefelter syndrome, and medications (opioids, glucocorticoids, some antidepressants). Testicular injury, infection (orchitis), or cancer treatment (chemotherapy, radiation) can also reduce production.

High testosterone in women is most commonly associated with polycystic ovary syndrome (PCOS), a condition characterised by irregular periods, ovarian cysts, and hyperandrogenism. Other causes include adrenal disorders (congenital adrenal hyperplasia, adrenal tumours), ovarian tumours, and medications (anabolic steroids, danazol). In men, exogenous testosterone use (anabolic steroids) raises levels supraphysiologically.

Low testosterone in men may present with fatigue, decreased libido, erectile dysfunction, mood changes (depression, irritability, difficulty concentrating), decreased muscle mass, increased body fat (especially abdominal), reduced bone density, decreased body hair, and sometimes breast tissue enlargement (gynecomastia). Symptoms often develop gradually and may be attributed to aging or stress before the diagnosis is made.

High testosterone in women can cause hirsutism (excess facial and body hair), acne, deepening of the voice, irregular or absent periods, male-pattern hair loss, and weight gain. In the context of PCOS, infertility is a common concern. Elevated androgens can also affect metabolic health, increasing the risk of insulin resistance and cardiovascular disease.

When evaluating testosterone abnormalities, your doctor will consider the clinical context and often order additional tests. LH and FSH help distinguish primary from secondary hypogonadism: high LH/FSH with low testosterone suggests testicular failure, while low LH/FSH suggests a pituitary or hypothalamic problem.

SHBG (sex hormone-binding globulin) affects how much testosterone is biologically available; conditions like obesity lower SHBG, while hyperthyroidism and liver disease raise it. Free testosterone or calculated free testosterone provides additional clarity. Other commonly ordered tests include prolactin (elevated prolactin can suppress testosterone), thyroid function, estradiol (in men with gynecomastia), and DHEA-S or 17-hydroxyprogesterone (in women with suspected adrenal androgen excess).

Men should talk to their doctor if they experience persistent fatigue, decreased libido, erectile dysfunction, mood changes, or loss of muscle mass—especially if a blood test shows low testosterone. The diagnosis of hypogonadism requires at least two morning blood samples showing low total testosterone, combined with consistent symptoms, before treatment is considered.

Women should consult their doctor if they notice excess hair growth, acne, irregular periods, or difficulty conceiving, as these may indicate elevated androgens. A hormonal workup can help determine whether PCOS, adrenal disorders, or other conditions are responsible. Early diagnosis and management can improve both symptoms and long-term health outcomes.

Norya does not diagnose—we help you prepare. Upload your blood test report at noryaai.com/analyze and receive a clear, structured summary that highlights your testosterone level alongside related hormonal markers like LH, FSH, and SHBG. The report flags out-of-range values and provides context so you can have a more informed discussion with your doctor.

Whether you are investigating symptoms of low testosterone or monitoring a hormonal condition, Norya organises your results so you can focus on the conversation that matters. For plan options and pricing, visit our pricing page.

This guide is for informational purposes only and does not replace medical advice or diagnosis. Always discuss your results with a healthcare professional. Start analysis with Norya