Testosterone
Also known as: Total Testosterone
What Does Testosterone Measure?
Testosterone is the primary male sex hormone, though it is present and important in both males and females. A total testosterone test measures the overall amount of testosterone circulating in the bloodstream, including both the portion bound to proteins (such as sex hormone-binding globulin and albumin) and the smaller fraction that is 'free' or unbound. This test is typically performed on a blood sample drawn in the morning, when testosterone levels are naturally at their highest point in the day.
Why Does Testosterone Matter?
Testosterone plays a critical role in a wide range of bodily functions beyond sexual health, including muscle mass maintenance, bone density, red blood cell production, mood regulation, cognitive function, and energy levels. In men, it drives puberty, sperm production, and libido. In women, it contributes to bone strength, sexual desire, and overall vitality. Abnormal testosterone levels — either too high or too low — can signal underlying health conditions such as hormonal disorders, metabolic dysfunction, or reproductive issues, making it an essential marker for diagnosing and monitoring many medical conditions.
Normal Ranges
Males
300–1,000 ng/dL (10.4–34.7 nmol/L) for adult males
Females
15–70 ng/dL (0.5–2.4 nmol/L) for adult females
Children
Varies by age and pubertal stage; prepubertal children typically <30 ng/dL
Causes of High Levels
- Anabolic steroid or exogenous testosterone use
- Polycystic ovary syndrome (PCOS) in women
- Congenital adrenal hyperplasia (CAH)
- Testosterone-secreting tumors of the adrenal glands or testes/ovaries
- Early-onset puberty (precocious puberty) in children
- Obesity-related hormonal imbalance (in some cases due to peripheral conversion)
Causes of Low Levels
- Hypogonadism (primary or secondary failure of the testes or ovaries)
- Aging (testosterone naturally declines with age, especially after 30–40 in men)
- Obesity and metabolic syndrome
- Chronic stress and elevated cortisol levels
How to Improve Your Testosterone
Diet
- Consume adequate healthy fats (avocados, olive oil, nuts) as cholesterol is a precursor to testosterone synthesis
- Eat zinc-rich foods such as oysters, beef, pumpkin seeds, and legumes to support testosterone production
- Include vitamin D-rich foods like fatty fish, egg yolks, and fortified dairy to maintain hormonal balance
- Reduce processed foods, refined sugars, and excess alcohol, which can suppress testosterone levels
- Maintain adequate protein intake (0.7–1g per pound of body weight) to support muscle mass and hormonal health
Supplements
- Vitamin D3: 2,000–5,000 IU/day, particularly if deficient, has been shown to support testosterone levels
- Zinc: 25–45 mg/day elemental zinc for individuals who are deficient
- Ashwagandha (Withania somnifera): 300–600 mg/day of root extract, shown in clinical trials to modestly raise testosterone and reduce cortisol
- Magnesium: 200–400 mg/day, as deficiency is associated with lower testosterone
- D-Aspartic Acid: 2–3 g/day may temporarily boost luteinizing hormone and testosterone in men with low levels
Related Biomarkers
Frequently Asked Questions
What is the difference between total testosterone and free testosterone?
Total testosterone measures all testosterone in the blood, including the portion bound to proteins like SHBG and albumin, plus the small unbound ('free') fraction. Free testosterone refers only to the unbound portion, which is biologically active and able to enter cells. Some people have normal total testosterone but low free testosterone due to high SHBG levels, so both tests together give a more complete picture of hormonal health.
What are the symptoms of low testosterone in men?
Symptoms of low testosterone (hypogonadism) in men include reduced sex drive, erectile dysfunction, fatigue and low energy, decreased muscle mass and strength, increased body fat (particularly around the abdomen), mood changes such as depression or irritability, difficulty concentrating, reduced bone density, and decreased body or facial hair. Not all men with low testosterone experience all symptoms, which is why lab testing is important for diagnosis.
Can women have high testosterone and what does it mean?
Yes, women can have elevated testosterone levels, and it is most commonly associated with polycystic ovary syndrome (PCOS). Symptoms in women can include irregular or absent menstrual periods, excess facial or body hair (hirsutism), acne, thinning hair on the scalp, and difficulty conceiving. Other causes include congenital adrenal hyperplasia and, rarely, androgen-secreting tumors. A healthcare provider should evaluate elevated testosterone in women to determine the underlying cause.