Biological Age: Blood Test Markers That Reveal Your Ageing Rate

A passport age is nothing more than a date of birth. Biological age reflects how quickly tissues, vessels and organs are actually wearing out. Two people born in the same year can differ by 15–20 years in metabolic health, inflammation burden and cellular repair capacity. The good news: the gap between calendar and biological age is measurable — not by subjective feelings, but by specific markers in a blood test.

What Is Biological Age and Why It Matters More Than Your Passport Age

Biological age is an integrated assessment of physiological state relative to population norms. It is determined not by the calendar but by the pace of molecular and cellular wear: accumulation of DNA damage, the level of chronic inflammation, mitochondrial health and the rate of protein renewal.

Calendar age predicts chronic disease risk only approximately. Biological age does so far more accurately. In large cohort studies, people whose biological age was 5+ years "younger" than their chronological age had roughly half the risk of cardiovascular events, dementia and cancer. The difference is built up year by year — and year by year it can be corrected.

A standard preventive check-up assesses the presence of disease, not the pace of its approach. A biological age panel addresses a different question: where on the trajectory are you now — and is there time to change course before symptoms appear?

Inflammation as the Engine of Ageing: hs-CRP

Chronic low-grade inflammation is one of the primary drivers of accelerated ageing. It produces no pain or fever, yet silently damages endothelial cells, accelerates atherosclerosis, disrupts insulin signalling and exhausts immune reserves.

C-reactive protein in its high-sensitivity form (hs-CRP) is the most accessible marker of this process. The laboratory normal of up to 5 mg/L is too wide a range for longevity assessment. The functional optimum: below 1 mg/L. A value of 1–3 mg/L corresponds to intermediate cardiovascular risk; above 3 mg/L — high risk, regardless of cholesterol level.

Hs-CRP above 2 mg/L alongside normal cholesterol is one of the most underappreciated findings: vascular risk is already elevated while a standard check-up shows nothing. This is why CRP measurement belongs in any meaningful biological age panel.

Homocysteine: A Marker of Vascular Age

Homocysteine is an amino acid that, when it accumulates, chemically erodes arterial walls from within. Its level reflects B-vitamin metabolism and indirectly signals "vascular age": chronically elevated homocysteine means arteries are ageing faster than the calendar suggests.

The laboratory upper limit is 15 µmol/L. The longevity optimum: below 10 µmol/L (below 8 µmol/L in women under 45). Each additional 5 µmol/L above normal raises stroke risk by 40–50% and approximately doubles myocardial infarction risk. Yet reducing homocysteine is one of the simplest interventions: normalising vitamins B12, B6 and folate is often sufficient.

Metabolic Age: HbA1c and Insulin

Glucose metabolism is one of the most informative thermometers of metabolic health. Disturbances develop over years before symptoms appear and are clearly visible in blood tests.

Glycated haemoglobin (HbA1c) reflects average glucose over 3 months. The laboratory normal is up to 6.0%. The longevity optimum: 4.8–5.4%. A value of 5.5–5.9% is already a risk zone even though it is formally "normal". Above 6.0% — prediabetes, with double the cardiovascular risk.

Fasting insulin is absent from the standard health check yet often explains everything else. In insulin resistance, the pancreas compensates for reduced tissue sensitivity by secreting progressively more insulin while glucose stays normal. The optimum: 3–8 µIU/mL. Insulin above 12 with normal blood sugar signals hidden insulin resistance and accelerated metabolic ageing.

Ferritin: Iron Store and Inflammation Marker

Ferritin in a biological age panel is read from two directions. Too low (below 30 µg/L) signals iron deficiency — reduced energy, impaired cognitive function and weakened immunity. Too high (above 200–250 µg/L in women, above 300 µg/L in men) is a marker of chronic inflammation or iron overload, which causes oxidative tissue damage.

The longevity optimum: 50–150 µg/L in women, 70–200 µg/L in men. In this range, ferritin acts as a buffer without becoming a source of oxidative stress. Ferritin must be interpreted alongside CRP: high ferritin with elevated CRP is an entirely different situation from high ferritin with normal CRP.

Vitamin D: The Longevity Hormone

Vitamin D is more accurately described as a hormone: its receptors are present in every cell of the body. It participates in immune regulation, inflammation control, mitochondrial function, muscle protein synthesis and apoptosis. Vitamin D deficiency accelerates biological ageing through several independent pathways.

The laboratory normal is 30–100 ng/mL. The longevity optimum based on prospective research: 50–80 ng/mL. Values below 20 ng/mL represent severe deficiency with elevated risk of autoimmune disease, cancer and cognitive decline. Below 30 ng/mL — insufficiency, at which the protective effects are not fully realised.

Uric Acid: An Underrated Metabolic Indicator

Uric acid was long considered a marker exclusively of gout. Current evidence shows: chronically elevated uric acid is an independent risk factor for hypertension, kidney disease and cardiovascular events. High uric acid almost invariably accompanies metabolic syndrome and insulin resistance.

The longevity optimum: below 350 µmol/L in women, below 400 µmol/L in men — substantially lower than what many laboratories list as the upper limit of normal. Falling uric acid is one of the markers of success in any anti-ageing programme: it reflects improved diet, reduced visceral fat and restored renal clearance.

How to Read a Biological Age Panel

No single marker works in isolation. Biological age is a pattern, not a single number. Several orientation points:

Green zone (optimal ageing pace): hs-CRP < 1 mg/L · homocysteine < 10 µmol/L · HbA1c 4.8–5.4% · fasting insulin 3–8 µIU/mL · ferritin 50–150 / 70–200 µg/L · vitamin D 50–80 ng/mL · uric acid < 350/400 µmol/L

Yellow zone (accelerated ageing, correctable): hs-CRP 1–3 · homocysteine 10–15 · HbA1c 5.5–5.9% · insulin 8–15 · ferritin < 30 or > 200/300 · vitamin D 20–30 ng/mL · uric acid > 400/450 µmol/L

Red zone (medical consultation needed): any marker persistently in the high-risk range plus two or more yellow markers simultaneously.

For a complete assessment, the panel is supplemented with a complete blood count and lipid panel — adding data on haemoglobin, platelet count, HDL and LDL.

What to Do When Markers Show Accelerated Ageing

One marker off target — a reason to adjust lifestyle. Three or more — a reason to consult a doctor and undergo extended investigation.

General correction principles regardless of the specific marker: reducing visceral fat (the primary source of chronic inflammation); strength and aerobic training (improve insulin sensitivity, lower CRP and uric acid); normalising sleep to 7–9 hours (reduces cortisol and inflammation); correcting B12, folate and B6 deficiencies (normalises homocysteine); supplementing vitamin D when levels fall below 40 ng/mL.

Re-testing the panel after 3–6 months of change is worthwhile. Biological age is neither a verdict nor a constant. Unlike calendar age, it can be moved in the right direction. The molecular mechanisms driving biological age accumulation are explained in the article ageing of the body: causes and mechanisms. A practical longevity programme and starting biomarker panel are in the article how to live long and healthy. An annual lab checklist with optimal target values is in the guide annual lab tests: longevity checklist. Extended lipid profile with ApoB for cardiovascular risk assessment — extended lipid profile and longevity.

This article is for informational purposes only. Interpretation of test results and clinical decisions are the responsibility of a qualified physician.