Stop guessing. Know your numbers

How your body handles sugar and stores energy — the base of long-term metabolic health.

• Fasting glucose

  mmol/L

  Your blood-sugar level after not eating overnight. A persistently raised fasting glucose is one of the earliest signs that the body is struggling to manage sugar, well before type-2 diabetes develops.

  Feeds your Metabolic Fitness score→What this means →

• HbA1c

  mmol/mol

  Glycated haemoglobin

  A single number that reflects your average blood sugar over the previous two to three months, so it smooths out day-to-day spikes. It's the standard marker for tracking long-term glucose control.

  Feeds your Metabolic Fitness score→What this means →

• Fasting insulin

  mIU/L

  HOMA-IR

  The amount of insulin circulating after a fast. Read alongside glucose, it flags insulin resistance early — often years before glucose itself starts to drift upward.

  Feeds your Metabolic Fitness score→What this means →

• Triglycerides

  mmol/L

  The main form of fat circulating in your blood. Raised triglycerides often travel with insulin resistance and are part of the wider picture of metabolic and heart health.

  Feeds your Metabolic Fitness score→

The particles and fats that drive cardiovascular risk — the numbers behind your heart age.

• Total cholesterol

  mmol/L

  The sum of the cholesterol carried across all your lipoprotein particles. It's a useful headline number, but the balance between the types below matters far more than the total alone.

  Feeds your Heart Age score→

• LDL cholesterol

  mmol/L

  LDL-C · 'Bad' cholesterol

  The cholesterol carried on low-density lipoproteins, the particles most associated with fatty build-up in artery walls. Lowering it is one of the best-evidenced ways to reduce cardiovascular risk.

  Feeds your Heart Age score→

• HDL cholesterol

  mmol/L

  HDL-C · 'Good' cholesterol

  Cholesterol carried on high-density lipoproteins, which help move cholesterol back to the liver. Higher levels are generally more favourable, though the relationship is more nuanced than 'more is always better'.

  Feeds your Heart Age score→

• ApoB

  g/L

  Apolipoprotein B

  There is one ApoB molecule on every atherogenic particle, so measuring it counts those particles directly — which can pin down cardiovascular risk more precisely than standard cholesterol alone.

  Feeds your Heart Age score→What this means →

• Lp(a)

  nmol/L

  Lipoprotein(a)

  A largely genetic particle that stays fairly stable through life, so a single measurement can reveal lifelong elevated heart-attack and stroke risk that ordinary cholesterol testing misses entirely.

  Feeds your Heart Age score→What this means →

Low-grade inflammation markers linked to how your body ages over time.

• hs-CRP

  mg/L

  High-sensitivity C-reactive protein

  A protein that rises with inflammation in the body. The high-sensitivity version picks up the low, chronic levels linked to cardiovascular and metabolic risk, rather than the big spikes of an acute infection.

  Feeds your Phenotypic Age score→

• Homocysteine

  µmol/L

  An amino acid that builds up when B-vitamin metabolism isn't working well. Raised levels are associated with cardiovascular risk and are often modifiable with folate and B12.

  What this means →

How your two main filtering organs are coping — quiet but important markers.

• Albumin

  g/L

  The most abundant protein in blood, produced by the liver. It reflects liver function and overall nutritional status, and tends to decline with age and ill health.

  Feeds your Phenotypic Age score→

• Creatinine

  µmol/L

  eGFR

  A muscle waste product cleared by the kidneys, so its level (and the eGFR estimated from it) is the standard way to check how well your kidneys are filtering.

  Feeds your Phenotypic Age score→

• ALT

  U/L

  Alanine aminotransferase

  An enzyme concentrated in the liver. When liver cells are under strain — from fatty liver, alcohol or other causes — more ALT leaks into the blood, making it a useful liver-health check.

• Alkaline phosphatase

  U/L

  ALP

  An enzyme found mainly in the liver and bones. It's used alongside the other liver markers to build a picture of liver and bone health.

  Feeds your Phenotypic Age score→

The make-up of your blood cells — oxygen delivery, immune status and more.

• White blood cell count

  ×10⁹/L

  WBC

  The total number of infection-fighting cells in your blood. Both high and low counts are informative, and the level is one of the markers used in biological-age scoring.

  Feeds your Phenotypic Age score→

• Lymphocyte percentage

  %

  The proportion of your white blood cells that are lymphocytes — the cells central to immune memory. The balance shifts with age, infection and immune health.

  Feeds your Phenotypic Age score→

• Mean corpuscular volume

  fL

  MCV

  The average size of your red blood cells. Cells that are unusually large or small can point to nutrient deficiencies (such as B12 or iron) and feed into biological-age estimates.

  Feeds your Phenotypic Age score→

• Red cell distribution width

  %

  RDW

  A measure of how much your red blood cells vary in size. A wider spread has emerged as a surprisingly strong marker of overall health and biological ageing.

  Feeds your Phenotypic Age score→

Signals that shape energy, mood, recovery and body composition.

• Testosterone

  nmol/L

  A hormone that influences muscle, bone, mood, energy and libido in all sexes (at different levels). It's commonly checked when energy, recovery or body composition aren't responding to training.

• TSH

  mIU/L

  Thyroid-stimulating hormone

  The signal your brain sends to control the thyroid, which sets your metabolic rate. It's the first-line check for an under- or over-active thyroid, a common cause of fatigue and weight change.

• Cortisol

  nmol/L

  The body's principal stress hormone, which also follows a daily rhythm. Measured in the morning, it gives a snapshot of your stress-response and adrenal signalling.

Common deficiencies that quietly sap energy, sleep and performance.

• Vitamin D

  nmol/L

  25-hydroxyvitamin D

  A vitamin (really a hormone) important for bone, immune and muscle health. Deficiency is very common, especially in winter, and is one of the more worthwhile things to know and correct.

• Vitamin B12

  pmol/L

  A vitamin needed for healthy nerves and red blood cells. Low levels cause fatigue and can be more common in plant-based diets and with age.

• Ferritin

  µg/L

  A measure of stored iron. Low ferritin is a leading cause of tiredness and poor training performance — particularly in menstruating and endurance athletes — while very high levels warrant a look too.

• Folate

  nmol/L

  Vitamin B9

  A B-vitamin that partners with B12 to make red blood cells and support nerve function. It also helps keep homocysteine in check.