Helvy
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Vitamins & Minerals
In the UK, the standard clinical (NHS) reference range for Vitamin B12 (Cobalamin) is 197-771 pg/mL, with 500-800 pg/mL considered the performance-optimised range. A result within these ranges suggests typical status; only a qualified clinician can interpret an individual reading.
Vitamin B12 is a water-soluble vitamin essential for DNA synthesis, red blood cell formation, and neurological function. It is exclusively found in animal-derived foods, making deficiency more common in vegetarians and vegans. B12 is stored in the liver, so deficiency can take years to develop but causes significant damage when it does.
Optimal range · UK
500-800 pg/mL
Performance-optimised band · clinical (NHS) range 197-771 pg/mL
Reference ranges for Vitamin B12, not a personal result. Any individual reading should be interpreted by a qualified clinician.
Optimal ranges
| Range | Value |
|---|---|
| Clinical (NHS) reference range | 197-771 pg/mL |
| Performance-optimised range | 500-800 pg/mL |
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
B12 is a cornerstone of energy metabolism and nervous system function. Even mildly low levels can cause fatigue, brain fog, and mood disturbances that are often attributed to stress or ageing. For men who train, B12 is critical for red blood cell production — directly influencing oxygen delivery to muscles. Men over 40 often have reduced absorption due to declining stomach acid production, making supplementation increasingly important regardless of dietary intake.
Symptoms
Low / Deficiency
High / Excess
Dietary sources
Supplementation
Methylcobalamin or hydroxocobalamin are the preferred bioavailable forms. Typical dose: 1,000-2,000 mcg daily sublingual or oral. Sublingual delivery bypasses potential absorption issues in the gut. B12 is water-soluble and non-toxic at high doses — excess is excreted. Often paired with folate (methylfolate) for optimal methylation support.
Testing
Vitamin B12 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 (197-771 pg/mL) and the performance-optimal range (500-800 pg/mL), 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
Vitamin B12 deficiency: recognition and management
Langan RC, Goodbred AJ
American Family Physician (2017)
DOI: 10.7326/0003-4819-138-7-200304010-00013Test for this
Related 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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