Total Testosterone: Normal Levels & What Yours Means

Why Total Testosterone Matters More Than You Think

When a man tells me he's been feeling wiped out, struggling to lose weight, or just not himself in the bedroom, my mind often goes straight to a simple blood test: total testosterone. It's a cornerstone hormone that influences far more than libido — it affects muscle mass, bone density, mood, and even red blood cell production.

In my clinical practice, I often see patients who have been attributing their fatigue or low mood to stress or aging, only to discover their testosterone is significantly low. Conversely, I've also seen women with unexplained acne and hair thinning whose total testosterone was unexpectedly high. That's why understanding this test is so important.

What Exactly Is Total Testosterone?

Total testosterone measures the sum of all testosterone in your blood — both the free (unbound) form and the fraction that's bound to proteins like sex hormone‑binding globulin (SHBG) and albumin. Most laboratories use the LOINC code 2986‑8 for this measurement, reported in nanograms per deciliter (ng/dL) or nanomoles per liter (nmol/L).

While free testosterone is the biologically active portion, total testosterone provides a reliable first‑screen for hormone imbalances. It's the test most commonly ordered when a doctor suspects hypogonadism, polycystic ovary syndrome (PCOS), or other endocrine disorders.

How the Test Is Done

The test itself is straightforward: a blood sample is drawn from a vein in your arm, typically in the morning (between 7 am and 10 am) because testosterone levels follow a circadian rhythm and peak early in the day. Fasting is not usually required, but your doctor may ask you to avoid strenuous exercise for 24 hours beforehand, as intense workouts can temporarily alter levels.

Reference Ranges for Total Testosterone (by Age and Gender)

Normal values vary significantly with age and sex. Below are typical ranges used in UK and US laboratories. Always interpret your results against the reference range provided by your specific lab.

Note: Ranges may differ slightly by laboratory. Always discuss your results with a healthcare professional.

What Do Low Total Testosterone Levels Mean?

Low total testosterone (hypogonadism) in men can present with reduced sex drive, erectile dysfunction, loss of body hair, decreased muscle mass, and mood changes. In my clinic, I've seen men with levels below 250 ng/dL who feel profoundly fatigued, yet once treatment is started, they often report a remarkable improvement in energy and wellbeing.

In women, low testosterone is less commonly discussed but can contribute to low libido, bone loss, and diminished sense of vitality. It's particularly relevant after menopause or following oophorectomy.

What Do High Total Testosterone Levels Mean?

High total testosterone in men is unusual but can occur with testicular tumors, adrenal disorders, or anabolic steroid use. Symptoms may include aggressive behaviour, acne, accelerated hair loss, and sleep apnoea. In women, elevated testosterone often points to polycystic ovary syndrome (PCOS), congenital adrenal hyperplasia, or ovarian tumours. Women may notice hirsutism, male‑pattern baldness, irregular periods, and deepening of the voice.

Is High Testosterone Dangerous?

Yes, persistently high testosterone — especially in men using exogenous steroids — increases the risk of cardiovascular events, liver damage, and infertility. In women, it can lead to metabolic complications if the underlying cause isn't addressed. A thorough evaluation by an endocrinologist is essential.

Total Testosterone in Women

Women often ask me why their testosterone is even checked. The answer: testosterone plays a vital role in female health — it supports bone density, muscle strength, and sexual function. Normal levels in women are much lower than in men, but even minor imbalances can cause symptoms. I've treated women with total testosterone levels below 10 ng/dL who experienced significant improvements with low‑dose testosterone therapy after ruling out other causes.

Factors That Can Skew Your Results

• Time of day: Levels peak in the morning. An afternoon test can underestimate true levels by 30–50%.
• Medications: Opioids, glucocorticoids, and some anticonvulsants can lower testosterone. Anabolic steroids and testosterone replacement therapy will increase it.
• Obesity: Excess adipose tissue increases conversion of testosterone to oestradiol, lowering total testosterone.
• Illness: Acute illness, surgery, or chronic conditions can temporarily suppress production.
• Sleep deprivation: Even a single night of poor sleep can reduce morning testosterone by 10–15%.

How to Prepare for a Testosterone Test

My advice is simple: schedule your blood draw for early morning (before 10 am), get a good night's sleep, avoid alcohol for 24 hours, and skip heavy exercise the day before. If you're on testosterone replacement therapy, your doctor will advise the optimal timing — usually just before your next dose. Fasting is not required, but it can help if your doctor orders additional tests like glucose or lipids.

One point I stress with my patients: don't panic about a single abnormal result. Testosterone can fluctuate, and we rarely make a diagnosis based on one reading alone. Confirmatory testing, along with free testosterone, LH, FSH, and prolactin, paints a clearer picture.