Helvy
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Metabolic
In the UK, the standard clinical (NHS) reference range for ALT (Alanine Aminotransferase) is 0-41 U/L, with 10-26 U/L considered the performance-optimised range. A result within these ranges suggests typical status; only a qualified clinician can interpret an individual reading.
ALT (alanine aminotransferase) is an enzyme found primarily in liver cells. When the liver is damaged or inflamed, ALT leaks into the bloodstream — making it one of the most sensitive markers of liver health. ALT is more specific to the liver than AST, which is also found in muscle and heart tissue.
Optimal range · UK
10-26 U/L
Performance-optimised band · clinical (NHS) range 0-41 U/L
Reference ranges for ALT, not a personal result. Any individual reading should be interpreted by a qualified clinician.
Optimal ranges
| Range | Value |
|---|---|
| Clinical (NHS) reference range | 0-41 U/L |
| Performance-optimised range | 10-26 U/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
Your liver is the body's detoxification centre, metabolising everything from alcohol and paracetamol to protein and hormones. Elevated ALT often appears long before symptoms — catching liver stress early is critical. For active men, ALT can be mildly elevated after intense exercise (particularly resistance training), so timing matters. More concerning elevations indicate fatty liver disease (NAFLD), which affects an estimated 25-30% of UK adults and is the leading cause of liver disease in the developed world. NAFLD is strongly linked to insulin resistance and visceral fat, making ALT a valuable metabolic screening marker.
Symptoms
Low / Deficiency
High / Excess
Dietary sources
Supplementation
There are no supplements that directly lower ALT — the goal is to address the underlying cause. For fatty liver: weight loss of 5-10% body weight is the most effective intervention, combined with reduced sugar intake and regular exercise. Milk thistle (silymarin) is widely marketed for liver health but evidence is mixed; it may offer modest benefit in specific liver conditions. NAC (N-acetylcysteine) supports glutathione production and is used clinically for paracetamol overdose but evidence for general liver protection is limited. The best approach is lifestyle: moderate alcohol, healthy weight, regular exercise, and adequate sleep.
Testing
ALT 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 (0-41 U/L) and the performance-optimal range (10-26 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
Global epidemiology of nonalcoholic fatty liver disease — meta-analytic assessment of prevalence, incidence, and outcomes
Younossi ZM, Koenig AB, Abdelatif D, et al.
Hepatology (2016)
DOI: 10.1002/hep.28431Related biomarkers
Related guides
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.
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