Vitamin B6 levels: what's normal, high and low
A B vitamin involved in protein metabolism, neurotransmitter synthesis, and immune function.
Medically reviewed by Youmna DiStefano, MD · Last reviewed September 2026
The short answer
Vitamin B6 is measured with a standard blood draw; no fasting is needed. A typical reference range is 20.0 – 125 nmol/L. At TestWell it's $51.99 all-in as Vitamin B6 (Pyridoxine), results in 3–5 business days, drawn at Quest or Labcorp. An out-of-range result is a prompt to look closer, not a diagnosis.
- Units
- nmol/L / ng/mL
- Sample
- Blood draw
- Fasting
- Not required
- Results
- 3–5 business days
- Price
- $51.99
- Labs
- Quest or Labcorp · BioReference in NY/NJ
Vitamin B6 Reference Range
These are the typical adult reference ranges used by major US labs. Your report will include the specific range used by the lab that processed your sample.
| Population | Range |
|---|---|
| age 18+ | 20.0 – 125 nmol/L |
Reference ranges are educational. Always interpret your result with the specific range printed on your lab report and discuss anything outside the range with a clinician.
Have a result in hand? analyze it with your AI assistant using these reviewed ranges, or run it through our explainer. Tools: look up another marker's range · convert lab units
What your Vitamin B6 result may mean
Usually reflects supplement use. Excess can cause nerve damage at high doses.
What a high Vitamin B6 means: causes, symptoms, next steps ↓Can reflect alcohol use, certain medications, or absorption issues.
What a low Vitamin B6 means: causes, symptoms, next steps ↓Educational only — not a diagnosis. Many factors can influence a single result. Discuss anything that concerns you with a healthcare provider.
What does a high Vitamin B6 mean?
High vitamin B6 almost always comes from supplements — B-complex, energy drinks, 'nerve support' formulas and some multivitamins deliver many times the daily requirement — and matters because excess B6 can itself cause the nerve damage people take it to prevent: numbness and tingling in the feet and hands. Stopping the supplement is the treatment; levels fall within weeks.
Common causes of a high Vitamin B6
- B6 or B-complex supplements, energy drinks, fortified products
- Some 'hair, skin and nail' and 'nerve' formulations
- Rarely, blood disorders that raise circulating B6
Ordered from most to least common.
Symptoms that can go with it
- Often none
- Tingling, numbness or burning in the feet and hands, unsteadiness when toxic
What clinicians usually check next
- Inventory every supplement and drink for pyridoxine content
- Stop the sources and retest in 6–8 weeks
- Neurological review if symptoms are present
How much B6 is too much?
The tolerable upper intake for adults is 100 mg/day; neuropathy has been reported with long-term intake above that and occasionally below it. Most people who test high are getting 50–200 mg a day from supplements or energy drinks without realizing it.
Educational only — not a diagnosis. A single result outside the range is a prompt to look closer with a clinician.
What does a low Vitamin B6 mean?
Low vitamin B6 occurs with alcohol use, kidney disease, malabsorption, autoimmune and inflammatory conditions, and several medications — isoniazid, hydralazine, some anticonvulsants, oral contraceptives. It contributes to anemia, dermatitis, mood symptoms and raised homocysteine. Diet alone rarely causes it in the US except with very restricted eating.
Common causes of a low Vitamin B6
- Alcohol use disorder
- Medications: isoniazid, hydralazine, penicillamine, levodopa-carbidopa, some anticonvulsants, oral contraceptives
- Malabsorption, celiac disease, kidney disease on dialysis
- Chronic inflammation and autoimmune disease
- Restricted diets, older age
Ordered from most to least common.
Symptoms that can go with it
- Fatigue, irritability, low mood
- Cracks at the corners of the mouth, scaly rash, sore tongue
- Tingling, confusion in severe deficiency
What clinicians usually check next
- CBC (microcytic anemia can result), homocysteine
- Medication and alcohol review
- Retest 8–12 weeks after correcting the cause
Follow-up tests at TestWell: CBC with Differential ($21.99), Homocysteine ($27.99).
Should I supplement if my B6 is low?
Correcting a documented deficiency is reasonable at modest doses; the trap is high-dose long-term use, which causes neuropathy. A clinician sets the dose and duration.
Educational only — not a diagnosis. A single result outside the range is a prompt to look closer with a clinician.
How do you get a Vitamin B6 test?
Order online, a licensed physician reviews the requisition, and you walk into a nearby lab for the draw. Vitamin B6 is available on its own or inside these panels — panels cost less per marker when you want the fuller picture.
| Option | Includes | Price |
|---|---|---|
| Vitamin B6 (Pyridoxine) | This marker only | $51.99 |
Quest vs. Labcorp for Vitamin B6: which lab should you pick?
Both are CLIA-certified national labs and the result is clinically equivalent, so pick whichever location is closer. Your report will print that lab's own reference range, which can differ slightly from the table above.
| Lab | Available | Price |
|---|---|---|
| Quest Diagnostics | Yes | $51.99 |
| Labcorp | Yes | $51.99 |
| BioReference (NY & NJ) | Yes | $51.99 |
Need help choosing a location? Use the lab finder to see draw sites near your ZIP.
Related Vitamins & Nutrients biomarkers
Markers commonly tested alongside Vitamin B6.
Frequently asked
What does a high Vitamin B6 mean?
High vitamin B6 almost always comes from supplements — B-complex, energy drinks, 'nerve support' formulas and some multivitamins deliver many times the daily requirement — and matters because excess B6 can itself cause the nerve damage people take it to prevent: numbness and tingling in the feet and hands. Stopping the supplement is the treatment; levels fall within weeks.
How much B6 is too much?
The tolerable upper intake for adults is 100 mg/day; neuropathy has been reported with long-term intake above that and occasionally below it. Most people who test high are getting 50–200 mg a day from supplements or energy drinks without realizing it.
What does a low Vitamin B6 mean?
Low vitamin B6 occurs with alcohol use, kidney disease, malabsorption, autoimmune and inflammatory conditions, and several medications — isoniazid, hydralazine, some anticonvulsants, oral contraceptives. It contributes to anemia, dermatitis, mood symptoms and raised homocysteine. Diet alone rarely causes it in the US except with very restricted eating.
Should I supplement if my B6 is low?
Correcting a documented deficiency is reasonable at modest doses; the trap is high-dose long-term use, which causes neuropathy. A clinician sets the dose and duration.
Do I need a doctor's order to test my vitamin b6?
No. TestWell's licensed physician network reviews and approves your order — usually within minutes. You can place an order online without an in-person visit or a referral from your own doctor.
How long does it take to get Vitamin B6 results?
Most Vitamin B6 results are available in 1–3 business days after your specimen arrives at the lab. You'll get an email the moment your results are ready, with everything viewable in your TestWell portal.
How much does a Vitamin B6 test cost?
Our Vitamin B6 (Pyridoxine) starts at $51.99. That's the all-in price — no copays, no insurance hoops, no surprise bills. HSA and FSA cards are accepted.
Do I need to fast before my Vitamin B6 test?
Fasting is not required for the Vitamin B6 test. You can have your blood drawn any time of day.
Which lab will process my Vitamin B6 test?
Your test will be processed by Quest Diagnostics, Labcorp, or BioReference depending on which is closest to you and which lab carries the test. All three are CLIA-certified and trusted by hospitals nationwide. You'll choose your lab during checkout from 4,000+ locations.
Ready to test your vitamin b6?
Order in two minutes, get physician-approved, and visit a lab the same day. Starts at $51.99.