How Is My Everlab Biological Age Calculated?

At Everlab, we don't just look at how many years you've been alive (your chronological age). We measure how your body is actually functioning. To do this, we use the PhenoAge algorithm.

The PhenoAge model is internationally validated and widely used in longevity research. It estimates your biological age by combining your chronological age with nine specific blood biomarkers that are strongly linked to ageing and long-term health outcomes.

How the Algorithm Works

PhenoAge does not use "normal versus abnormal" cut-offs. It uses your exact values. A result sitting at the higher end of the optimal reference range contributes differently from one at the lower end, even though both may be reported as within range. This means your biological age can shift in either direction between blood draws without any individual result becoming flagged as abnormal.

Every biomarker has a fixed weight and a direction of influence. Seven of the nine markers push biological age higher when they rise, meaning lower levels are protective. The remaining two, albumin and lymphocyte percentage, push biological age lower when they rise, meaning higher levels are protective.

Chronological age provides the largest single input and anchors the calculation. The nine biomarkers then raise or lower your biological age relative to what is expected for someone your chronological age.

The Nine Biomarkers and How They Influence Your Score

Significant influence

Red cell distribution width (RDW): Higher levels increase biological age. RDW measures the variability in size of your circulating red blood cells and is one of the strongest individual predictors of all-cause mortality in healthy adults, which is why PhenoAge weights it heavily. Higher RDW means the bone marrow is producing red cells of less uniform size, often associated with chronic inflammation, oxidative stress, and reduced bone marrow efficiency.

Fasting glucose (Fasting BSL): Higher levels increase biological age. Fasting glucose reflects insulin sensitivity and glucose regulation at rest. A higher fasting glucose, even within the normal range, indicates earlier metabolic dysregulation and is associated with increased cardiovascular risk, vascular damage, and accelerated cellular ageing.

Serum creatinine: Higher levels increase biological age. Creatinine is a breakdown product of muscle metabolism cleared by the kidneys. Higher creatinine usually reflects reduced kidney filtration, one of the most reliable markers of biological ageing because kidney function declines progressively with age and predicts cardiovascular and all-cause mortality. One caveat: creatinine is also raised by high muscle mass and recent protein intake, so in muscular individuals it can overestimate biological age. In most people, lower creatinine signifies better preserved kidney function.

Moderate influence

Mean corpuscular volume (MCV): Higher levels increase biological age. MCV is the average size of your red blood cells. Higher MCV is associated with reduced cellular turnover efficiency, B12 or folate insufficiency, alcohol intake, thyroid dysfunction, or bone marrow stress. Even at the upper end of the normal range, higher MCV is associated with greater mortality risk in population studies.

Serum albumin: Lower levels increase biological age. Albumin is the main protein in your blood, produced by the liver. It reflects liver function, nutritional status, and the absence of inflammation. Higher albumin signifies good liver function, adequate protein nutrition, and low inflammatory burden, all of which are associated with longer life. Lower albumin signifies the opposite, even when still technically within range.

Ultra-sensitivity C-reactive protein (hsCRP): Higher levels increase biological age. hsCRP reflects systemic inflammation, which accelerates vascular ageing, insulin resistance, and tissue damage over time.

Total white cell count: Higher levels increase biological age. Your total white cell count is calculated from five white cell types: neutrophils (the largest group, responsible for immediate response to bacterial infection), lymphocytes (immune cells that provide long-term protection), monocytes, eosinophils, and basophils. A higher count indicates greater ongoing immune activity, often from chronic low-grade inflammation, visceral adiposity, stress, or acute infection. Persistent elevation, even within range, is associated with increased cardiovascular events and mortality.

Lymphocyte percentage: Lower levels increase biological age. Lymphocyte percentage reflects the extent to which your adaptive immune system (the part that builds long-term, targeted protection) is contributing to the total white cell count. A higher percentage signifies a healthy adaptive immune compartment and a lower acute inflammatory response. A lower percentage often reflects acute stress, inflammation, and immune exhaustion, all associated with worse health outcomes. This is why lymphocyte percentage is protective in the algorithm.

Slight influence

Alkaline phosphatase (ALP): Higher levels increase biological age. ALP is produced primarily in the liver and bone. Higher levels can reflect increased bone turnover and liver stress, and are associated with increased cardiovascular and all-cause mortality. Lower ALP signifies lower liver inflammation and slower bone turnover.

Why Your Biological Age Can Fluctuate

Because PhenoAge uses your exact biomarker values rather than pass/fail thresholds, every marker naturally fluctuates between blood draws depending on hydration, recent illness, exercise, time of day, fasting status, sleep, and stress. Your calculated biological age can shift in either direction without any individual result becoming abnormal.

This is normal and expected. It is also why we recommend standardising your testing conditions to get the most consistent, comparable results over time.

For the most reliable comparison between tests:

• Use the same laboratory each time.
• Test at the same time of day.
• Fast before your blood draw (as directed by your Care team).
• Arrive well hydrated.
• Avoid intense exercise for 24 to 72 hours before the test.
• Wait at least two weeks after any acute illness before testing.

Why Can't I See My Biological Age Yet?

If your biological age is not yet visible in your Everlab app, it is usually for one of two reasons.

Pending results: All nine biomarkers must be processed to calculate an accurate score. If you haven't completed your pathology or results are still pending, the calculation cannot be finalised.

Awaiting your review: Your biological age is typically released following your Review Consultation with your practitioner, where they walk you through what the results mean for your personalised health plan.

A Dynamic Measurement

Your biological age is not a fixed number. It updates as you complete new testing throughout your health plan, allowing you to track the real-time impact of your lifestyle changes and interventions over time.