What is a testosterone test?
A testosterone blood test measures the level of testosterone circulating in your blood. Total testosterone measures both bound (attached to proteins) and free testosterone. Free testosterone is the biologically active portion. Testing is done in the morning (7-10am) when levels peak. In men, testosterone is primarily produced by the testes. In women, it is produced in smaller amounts by the ovaries and adrenal glands.
Testosterone normal range
| Group | Total Testosterone (ng/dL) | Interpretation |
|---|---|---|
| Adult men | 300 – 1,000 | Normal |
| Adult men (low) | < 300 | Low T — hypogonadism |
| Adult women | 15 – 70 | Normal |
| Women (high) | > 70 – 80 | Elevated — investigate PCOS/adrenal cause |
| Prepubertal children | < 10 | Low (normal for age) |
LOW Testosterone in Men — Hypogonadism
Low testosterone (hypogonadism) causes: reduced libido and sexual dysfunction, fatigue and low energy, decreased muscle mass, increased body fat (especially belly fat), mood changes and depression, reduced bone density (osteoporosis risk), decreased beard and body hair growth. Causes include: primary hypogonadism (testes problem — e.g., Klinefelter syndrome, testicular injury, mumps orchitis), secondary hypogonadism (pituitary or hypothalamic problem — e.g., pituitary tumour, opioid use), obesity, type 2 diabetes, chronic illness, and ageing (testosterone naturally declines ~1% per year after 30).
HIGH Testosterone in Women — Hyperandrogenaemia
High testosterone in women most commonly indicates PCOS (polycystic ovary syndrome), which affects 5-10% of reproductive-age women. Other causes: congenital adrenal hyperplasia (CAH), adrenal or ovarian tumours (rare). Symptoms: acne, hirsutism (excess facial and body hair), irregular or absent periods, scalp hair thinning, and in severe cases deepening of voice.
Other tests done with testosterone
| Test | Why ordered |
|---|---|
| LH and FSH | Distinguish primary (testes) from secondary (pituitary) hypogonadism |
| SHBG | Sex hormone binding globulin; helps calculate free testosterone |
| Prolactin | High prolactin suppresses testosterone |
| DHEA-S | Adrenal androgen; elevated in adrenal causes of high testosterone |
| Thyroid (TSH) | Thyroid disease affects sex hormone levels |
Questions to ask your doctor
- Is my testosterone result truly low or within normal for my age?
- Do I need LH, FSH and prolactin tested too?
- Am I a candidate for testosterone replacement therapy?
- Could my medication (opioids, steroids, antidepressants) be lowering my testosterone?
- If I am a woman with high testosterone, do I need an ultrasound for PCOS?