Guide
Vitamin B12 and nerves: why a B12 test comes before a supplement
Vitamin B12 and nerves are linked: NIH says a B12 shortage can cause numbness and tingling in the hands and feet, even without anemia. A clinician can order a B12 test. B12 is not one of the six named ingredients in Flow Nerves, so the capsule is not a B12 fix. Sudden one-sided numbness is a 911 call.
Written by the Flow Nerves label deskUpdated
The link
Can low vitamin B12 cause nerve problems?
Yes. NIH says a vitamin B12 shortage can cause numbness and tingling in the hands and feet, and that this can happen without anemia (NIH ODS, Vitamin B12).
That last point matters. A normal blood count does not rule B12 out. NINDS also lists B12 deficiency among the causes of peripheral neuropathy (NINDS, Peripheral neuropathy). Mayo Clinic lists low B vitamins too (Mayo Clinic, Peripheral neuropathy).
The same agency pages list diabetes, alcohol, some medicines and pressure on a nerve. B12 is one cause among several, which is why the order is: find the cause, then decide on a product.
What the health agencies say can cause nerve symptoms in the hands and feet
Cause 1 of 5
Diabetes
The leading cause of peripheral neuropathy in the U.S.; about two-thirds of people with diabetes have some nerve problem (NINDS)
(NINDS, Peripheral neuropathy) (Mayo Clinic, Peripheral neuropathy) (NIH ODS, Vitamin B12)
Cause 2 of 5
Vitamin B12 shortage
Can cause numbness and tingling in hands and feet, even without anemia; metformin and acid reducers can lower B12 absorption (NIH)
(NINDS, Peripheral neuropathy) (Mayo Clinic, Peripheral neuropathy) (NIH ODS, Vitamin B12)
Cause 3 of 5
Alcohol, medicines, toxins
Alcohol use disorder, some cancer, heart, infection and seizure medicines, and toxins (NINDS, Mayo Clinic)
(NINDS, Peripheral neuropathy) (Mayo Clinic, Peripheral neuropathy) (NIH ODS, Vitamin B12)
Cause 4 of 5
Pressure on a nerve
A cast, crutches, repetitive motion or an injury (Mayo Clinic)
(NINDS, Peripheral neuropathy) (Mayo Clinic, Peripheral neuropathy) (NIH ODS, Vitamin B12)
Cause 5 of 5
Other conditions
Kidney, liver or thyroid disease, infections and autoimmune disease; sometimes no cause is found (Mayo Clinic)
(NINDS, Peripheral neuropathy) (Mayo Clinic, Peripheral neuropathy) (NIH ODS, Vitamin B12)
This is background from agency pages. A supplement cannot tell you which cause applies to you; a clinician's exam and tests can.
Who is at risk
Who is more likely to have low B12?
NIH names older adults, vegans and vegetarians, people with pernicious anemia or digestive disorders, and people who take metformin or acid reducers (NIH ODS, Vitamin B12).
| Group | Why it matters, per NIH |
|---|---|
| Older adults | Named as an at-risk group |
| Vegans and vegetarians | Named as an at-risk group |
| Pernicious anemia, digestive disorders or surgery | Named as an at-risk group |
| Metformin or acid reducers | Can lower B12 absorption |
If you take metformin or an acid reducer, keep taking it exactly as prescribed. Ask your clinician or pharmacist whether a B12 check makes sense for you.
Testing
Do you need a B12 test for numb or tingling feet?
Ask. A clinician can order a B12 test and decide what the result means for you, which a capsule cannot do.
Mayo Clinic says to seek medical care right away if you notice tingling, weakness or pain in your hands or feet (Mayo Clinic, Peripheral neuropathy). Tell the clinician about every supplement and medicine you take, and keep a record (NIH ODS, Dietary Supplements: What You Need to Know).
Sudden numbness or weakness, especially on one side, trouble speaking, seeing or walking, chest pain or trouble breathing: call 911. CDC lists the first group as stroke signs (CDC, Stroke signs and symptoms). A B12 question can wait for the visit; these cannot.
Vitamins
Is a nerve supplement vitamin the answer?
Not by itself. The agency pages say to find the cause, and a vitamin is only one of many possible causes.
NIH lists the recommended daily amount of B12 for adults as 2.4 mcg (NIH ODS, Vitamin B12). We do not tell readers whether to take B12, how much or in what form, because that depends on a test and on the person. Taking more of a vitamin is not a shortcut either: NIH says more might not be better (NIH ODS, Dietary Supplements: What You Need to Know), and NINDS lists too much vitamin B6 among causes of neuropathy (NINDS, Peripheral neuropathy).
If you already take a B-complex, magnesium or another nerve product, do not add a second one without asking a pharmacist. Doubling up is how people end up with more of an ingredient than they meant to take.
Flow Nerves capsule: 30 a bottle1 capsule a day per the seller's FAQ · 2, 3 or 6 bottles · 2 bottles at $79 each · other prices at checkout
See the priceThe capsule
Does Flow Nerves contain vitamin B12?
No. B12 is not one of the six named ingredients in Flow Nerves, so the capsule is not a B12 fix.
The seller names magnesium glycinate, alpha lipoic acid, butcher's broom root extract, L-carnitine, turmeric extract and coenzyme Q10 in a proprietary blend and prints no amount for any of them. We hold no Supplement Facts panel, so we cannot say what the real panel prints (Flow Nerves seller brief). Flow Nerves is a once-daily capsule, not a gummy or a liquid.
The bottle front reads “Nerve Support*”. We found no trial that tested that claim on this capsule. Ask your doctor or pharmacist first if you take warfarin or another blood thinner, insulin or diabetes medicine, thyroid hormone, antibiotics, seizure medicine or chemotherapy. Turmeric has liver injury reports in LiverTox; dark urine or yellow skin or eyes means stop and get care (LiverTox, Turmeric).
Next steps
What should you do first about possible B12 nerve symptoms?
Get the cause checked, ask about B12, and tell your team what you take.
- Find the causePeripheral neuropathy has more than 100 types, and diabetes is the leading cause in the U.S. (NINDS). A clinician decides which applies. (NINDS, Peripheral neuropathy)
- Ask about vitamin B12B12 deficiency can cause numbness and tingling in hands and feet without anemia; metformin and acid reducers can lower absorption (NIH). (NIH ODS, Vitamin B12)
- Check blood sugarNIDDK describes nerve damage as a diabetes complication; testing and care come before any supplement. (NIDDK, Diabetic neuropathy)
- Review alcohol and medicinesMayo Clinic lists alcohol use disorder and some medicines, especially chemotherapy, among causes. (Mayo Clinic, Peripheral neuropathy)
- Take pressure off the nerveCasts, crutches and repetitive motion can compress nerves (Mayo Clinic). (Mayo Clinic, Peripheral neuropathy)
- Tell your team what you takeNIH says to tell every provider about every supplement and keep a record; more might not be better. (NIH ODS, Dietary Supplements: What You Need to Know)
More on this in the when to see a clinician guide and the foot tingling causes guide. The ingredients page lists the six names in the capsule.
FAQ
B12 and nerve questions
Can you have B12 deficiency without anemia?
Yes. NIH says a B12 shortage can cause numbness and tingling in the hands and feet without anemia. A normal blood count alone does not rule it out, so ask a clinician about a B12 test.
What is the B12 deficiency neuropathy link?
NINDS lists B12 deficiency among causes of peripheral neuropathy, and NIH links it to numbness and tingling. A clinician decides whether it applies to you. We found no source that Flow Nerves addresses it.
Does metformin affect vitamin B12?
NIH says metformin and acid reducers can lower B12 absorption. Keep taking prescribed medicine exactly as directed and ask your clinician or pharmacist whether a B12 check fits.
How much B12 should an adult get?
NIH lists the recommended daily amount for adults as 2.4 mcg. Whether you need a supplement is a question for a clinician and a test, not a number from this site.
Can I take Flow Nerves instead of a B12 test?
No. Flow Nerves is a capsule, not a test, and B12 is not among its six named ingredients. A capsule cannot tell you why your hands or feet tingle.
Who wrote this
Written and reviewed by
Pages built from the bottle render, the seller's brief and linked NIH, FDA, CDC, FTC and peer-reviewed sources.
Last updated . Read our editorial standards and how we check reviews. This website is the information site of a licensed U.S. retail desk for Flow Nerves. It is not the manufacturer, and we have not been given the name of the maker. We earn money when you buy through our order links.
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