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Liver & Bone

Alkaline Phosphatase (ALP)

In the UK, the standard clinical (NHS) reference range for Alkaline Phosphatase (ALP) is 30-130 U/L, with 40-90 U/L considered the performance-optimised range. A result within these ranges suggests typical status; only a qualified clinician can interpret an individual reading.

Alkaline phosphatase is an enzyme present throughout the body but concentrated in liver, bone, intestine, and placenta. Total serum ALP reflects the combined activity of these isoenzymes — most often dominated by the liver and bone forms in adults. It is the second biomarker in the Levine PhenoAge composite, where steadily rising values track biological ageing.

Last reviewed: 11 June 2026


Optimal Ranges

What is the optimal range for ALP?

Clinical (NHS) Range

30-130 U/L

U/L

Performance-Optimised Range

40-90 U/L

U/L

Alkaline Phosphatase (ALP) reference ranges (UK)
RangeValueUnit
Clinical (NHS) reference range30-130 U/LU/L
Performance-optimised range40-90 U/LU/L

The clinical range defines what is considered medically “normal” — broad enough to cover 95% of the population. The performance range reflects where research and clinical experience suggest most people feel and function at their best. A result in either range suggests typical status and is not a diagnosis; any individual reading should be interpreted by a qualified clinician.


Why It Matters

Why ALP matters for performance

Elevated ALP is the earliest blood signal of cholestatic liver problems (where bile flow is blocked) and is also a sensitive marker of bone turnover — useful in osteopenia, fracture risk, and vitamin D deficiency contexts. Low ALP is less common but can flag zinc or magnesium deficiency, hypothyroidism, or rare metabolic conditions. For longevity scoring, a stable ALP in the lower-middle of the reference range correlates with slower biological ageing.


Symptoms

What are the symptoms of low or high ALP?

Low / Deficiency

  • Often asymptomatic — found incidentally
  • Possible bone aches if from low zinc
  • Fatigue if underlying thyroid issue

High / Excess

  • Itching (from cholestasis)
  • Right-upper-quadrant abdominal discomfort
  • Bone pain (if from bone turnover)
  • Pale stools or dark urine (in obstructive picture)

Dietary Sources

Which foods support ALP levels?

ALP itself is endogenous — diet matters via its cofactorsZinc-rich foods: oysters, beef, pumpkin seedsMagnesium-rich foods: leafy greens, dark chocolate, almondsVitamin D from oily fish and sunlightVitamin B6 from poultry, fish, and chickpeas

Supplementation

How do you improve ALP levels?

If ALP is suboptimal-low, investigate zinc, magnesium, and B6 status first — these are the enzymatic cofactors. If ALP is rising, the next step is fractionation (bone vs liver) and a vitamin D check, not a supplement. ALP is read alongside GGT (liver) and calcium (bone) to localise the source.


Testing

How is ALP tested in the UK?

ALP is measured from a blood sample. With Helvy, that means a finger-prick kit taken at home and posted to a UKAS-accredited UK laboratory, with results in around 5 days, reviewed by a qualified clinician. Your result is reported against both the clinical range (30-130 U/L) and the performance-optimal range (40-90 U/L), so you can see not just whether you are “normal” but whether you are optimal. If you make a change, retest after 8-12 weeks to confirm it worked.


Research

Key study

An epigenetic biomarker of aging for lifespan and healthspan

Levine ME, Lu AT, Quach A, et al.

Aging (Albany NY) (2018)

DOI: 10.18632/aging.101414

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This content is for educational purposes only and does not constitute medical advice. Your data suggests areas for optimisation, but any concerns should be discussed with a qualified healthcare professional. If your results flag values outside safe ranges, we recommend consulting your GP.