Andropause (Male Menopause) Blood Test

The concept of "male menopause" generates heated debate in medical circles. Unlike female menopause — a definitive, time-limited event where oestrogen production falls by 90% over a few years — testosterone decline in men is gradual, variable, and far from universal. Testosterone drops by approximately 1–2% per year from age 30, but individual variation is enormous. Some 70-year-old men have testosterone levels that would be normal for a 30-year-old, while some 45-year-olds are clinically deficient.

The preferred medical term is "late-onset hypogonadism" or "testosterone deficiency syndrome" rather than "andropause" or "male menopause," but whatever you call it, the symptoms are real and measurable — as are the blood markers that identify it.

How Common Is Low Testosterone?

By age 50, approximately 40% of men have total testosterone below 12 nmol/L — the lower limit of the normal reference range used by most UK laboratories. The European Male Ageing Study (EMAS), which followed over 3,000 men, found that only about 2% of 40–79-year-old men met strict criteria for symptomatic late-onset hypogonadism (low testosterone plus specific symptoms). But many more had suboptimal levels with some degree of symptom burden.

The challenge is that symptoms of low testosterone overlap substantially with other common conditions. Fatigue, low libido, reduced muscle mass, increased body fat (particularly visceral), low mood, poor concentration, and erectile dysfunction can all be caused by depression, sleep apnoea, metabolic syndrome, hypothyroidism, or simply the cumulative effects of poor sleep, stress, and sedentary living. Blood testing is the only way to determine whether testosterone is actually the issue.

Total Testosterone, Free Testosterone, and SHBG

Total testosterone alone is an incomplete picture. Sex hormone-binding globulin (SHBG) rises with age — approximately 1–2% per year — binding more testosterone and reducing the free fraction that's biologically active. A man with a total testosterone of 15 nmol/L and SHBG of 60 nmol/L has significantly less bioavailable testosterone than a man with the same total testosterone and SHBG of 30 nmol/L.

Free testosterone — either measured directly or calculated from total testosterone, SHBG, and albumin — is a more accurate indicator of androgenic status. The calculated free testosterone (using the Vermeulen equation) below 0.225 nmol/L is generally considered deficient.

Testing must be done in the morning, before 10am, after an overnight fast. Testosterone follows a circadian rhythm, peaking between 6–8am and falling by 20–30% by late afternoon. Testing at 3pm will produce a misleadingly low result. BSSM (British Society for Sexual Medicine) guidelines specify morning sampling as mandatory for accurate assessment.

LH and FSH: Primary vs Secondary Hypogonadism

This is a critical distinction that's often overlooked. Testosterone is produced by the testes in response to luteinising hormone (LH) from the pituitary gland. If testosterone is low and LH is elevated (above 9.4 IU/L), the problem is in the testes — they're receiving the signal but can't respond adequately. This is primary hypogonadism.

If testosterone is low but LH is also low or inappropriately normal, the problem is upstream — the pituitary isn't sending sufficient signal. This is secondary hypogonadism, and it has different causes: obesity (the most common cause — adipose tissue aromatises testosterone to oestrogen, which suppresses LH), pituitary adenoma, medications (opioids are a notorious cause), haemochromatosis (iron overload damages the pituitary), or chronic illness.

FSH follows a similar pattern — elevated in primary failure, suppressed in secondary. The distinction matters because secondary hypogonadism has potentially reversible causes. Weight loss of 10% can increase testosterone by 2–3 nmol/L. Stopping opioids can restore the entire axis. Treatment of a pituitary adenoma can normalise everything. Testing LH and FSH alongside testosterone prevents missing these reversible causes.

Thyroid Function: Symptom Overlap

Hypothyroidism causes fatigue, weight gain, low mood, cognitive sluggishness, cold intolerance, and constipation — a symptom list that overlaps almost completely with testosterone deficiency. In the over-50 male population, both conditions are common enough that one can mask the other.

TSH and free T4 should be tested alongside testosterone to rule out thyroid dysfunction as either the primary cause of symptoms or a contributing factor. In some cases, treating hypothyroidism resolves symptoms that were attributed to low testosterone.

HbA1c: Diabetes Tanks Testosterone

The relationship between diabetes and testosterone is bidirectional and powerful. Obesity and insulin resistance suppress testosterone via increased aromatase activity (converting testosterone to oestradiol) and suppressed LH secretion. Simultaneously, low testosterone promotes visceral fat accumulation and insulin resistance — creating a self-reinforcing cycle.

Studies have shown that men with type 2 diabetes have testosterone levels approximately 2–3 nmol/L lower than age-matched non-diabetic men. Weight loss and metformin can improve both insulin sensitivity and testosterone levels. Testing HbA1c alongside testosterone identifies this metabolic overlap and prevents treating testosterone in isolation when metabolic dysfunction is the root cause.

Cortisol: Stress and Adrenal Function

Chronic stress elevates cortisol, which directly suppresses the hypothalamic-pituitary-gonadal axis. High cortisol inhibits GnRH secretion, reducing LH and therefore testosterone production. Morning cortisol provides a snapshot of adrenal function. Persistently elevated morning cortisol (above 550 nmol/L) warrants investigation for Cushing's syndrome if clinical features are present. Low morning cortisol (below 200 nmol/L) may indicate adrenal insufficiency.

In the context of suspected andropause, cortisol helps determine whether stress is a contributing factor to low testosterone and whether addressing stress might improve the hormonal picture without testosterone replacement.

Lipid Panel and Cardiovascular Risk

Testosterone has complex effects on cardiovascular health. Low testosterone is associated with increased cardiovascular risk — men with testosterone below 8 nmol/L have higher rates of coronary artery disease. However, testosterone replacement therapy has had a controversial safety profile regarding cardiovascular events, though the recent TRAVERSE trial showed no increased risk with careful monitoring.

A full lipid panel (total cholesterol, LDL, HDL, triglycerides) provides cardiovascular risk context. Men with low testosterone, elevated triglycerides, low HDL, and central obesity are in the metabolic syndrome category, where lifestyle intervention may simultaneously address all these markers.

Prolactin and Oestradiol

Prolactin is tested to exclude prolactinoma — a benign pituitary tumour that suppresses testosterone by inhibiting GnRH. Elevated prolactin (above 400 mU/L) in a man with low testosterone and low LH warrants pituitary MRI. Prolactinomas are treatable with medication (cabergoline) and are an important — if uncommon — reversible cause of male hypogonadism.

Oestradiol (E2) is relevant in men with significant visceral adiposity. Fat tissue contains aromatase, which converts testosterone to oestradiol. Elevated oestradiol contributes to gynaecomastia (breast tissue growth), further suppresses LH, and contributes to the low-testosterone cycle. Oestradiol above 150 pmol/L in a male suggests significant aromatisation and supports weight loss as a primary intervention.

When to Test

Men experiencing persistent symptoms suggestive of low testosterone — fatigue lasting more than a month, reduced libido, erectile dysfunction, loss of morning erections, declining muscle mass or strength, increasing visceral fat, or low mood — should test as a first step rather than assuming it's "just ageing."

Test in the morning before 10am, fasted, after a normal night's sleep. Avoid testing within 48 hours of heavy exercise, heavy alcohol intake, or acute illness — all of which transiently suppress testosterone. If the first result is low, always retest on a separate day (BSSM guidelines require two confirmed low readings before diagnosing hypogonadism).

Recommended Blood Tests

The Male Hormones Clarity 14 biomarker test (£110) is specifically designed for this assessment. It includes total testosterone, SHBG, free testosterone calculation, LH, FSH, oestradiol, prolactin, and thyroid function — covering the core hormonal workup needed to diagnose and categorise hypogonadism.

For a comprehensive assessment that also includes cardiovascular markers, HbA1c, liver and kidney function, vitamin D, and B12 alongside the hormonal panel, the Peak Insights 70 biomarker test (£185) provides the widest coverage — particularly valuable for men over 50 where multiple systems may be contributing to symptoms.

Low testosterone is not inevitable, and feeling tired and unmotivated at 55 is not something you should simply accept. A blood test takes 10 minutes and can distinguish between "this is ageing" and "this is treatable."