Helvy
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Vitamins & Minerals
In the UK, the standard clinical (NHS) reference range for Vitamin B6 (Pyridoxine) is 20-125 nmol/L, with 50-125 nmol/L considered the performance-optimised range. A result within these ranges suggests typical status; only a qualified clinician can interpret an individual reading.
Vitamin B6 (pyridoxal 5'-phosphate in its active form) is a water-soluble vitamin involved in over 150 enzymatic reactions. It is critical for amino acid metabolism, neurotransmitter synthesis (serotonin, dopamine, GABA), haemoglobin formation, and immune function. Unlike fat-soluble vitamins, B6 is not stored in significant quantities and must be replenished regularly through diet.
Optimal range · UK
50-125 nmol/L
Performance-optimised band · clinical (NHS) range 20-125 nmol/L
Reference ranges for Vitamin B6, not a personal result. Any individual reading should be interpreted by a qualified clinician.
Optimal ranges
| Range | Value |
|---|---|
| Clinical (NHS) reference range | 20-125 nmol/L |
| Performance-optimised range | 50-125 nmol/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
B6 is a cofactor in the production of key neurotransmitters — serotonin for mood, dopamine for motivation, and GABA for calm focus. Deficiency can directly impair mental performance and sleep quality. For active men, B6 supports the conversion of glycogen to glucose during exercise and is involved in steroid hormone modulation (it helps reduce excess oestrogen by supporting liver clearance). B6 also works with folate and B12 to regulate homocysteine — deficiency in any of the three raises cardiovascular risk.
Symptoms
Low / Deficiency
High / Excess
Dietary sources
Supplementation
Most B6 supplements use pyridoxine hydrochloride, but pyridoxal 5'-phosphate (P5P) is the active coenzyme form and may be better absorbed by those with liver impairment or genetic variants affecting conversion. Standard supplemental dose is 10-50mg daily. The UK tolerable upper limit is 200mg/day (long-term), but chronic doses above 100mg can cause reversible nerve damage. B6 is best taken as part of a B-complex rather than in isolation, as B vitamins work synergistically. Taking B6 in the morning may support daytime neurotransmitter production without disrupting sleep.
Testing
Vitamin B6 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 (20-125 nmol/L) and the performance-optimal range (50-125 nmol/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
Vitamin B6 and its role in cell metabolism and physiology
Parra M, Stahl S, Hellmann H
Cells (2018)
DOI: 10.3390/cells7070084Related biomarkers
Related guides
Vitamin B6 Blood Test UK
What it measures & the toxicity risk
Tingling & Numbness Blood Test UK
B6 toxicity is a classic cause of pins and needles
Homocysteine Blood Test UK
B6, B12 & folate clear it
Vitamin Deficiency Blood Test UK
Which vitamins to check & why
Sleep Blood Test UK
B6 supports melatonin production
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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