Vitamin B6: What It Does, How Much Is Too Much, and the Foods That Cover Your Day
Vitamin B6: What It Does, How Much Is Too Much, and the Foods That Cover Your Day
Most people learn one simple rule about vitamins. Fat-soluble ones get stored, so you can build up too much. Water-soluble ones wash out in your urine, so the extra does no harm.
That rule is too simple. Some water-soluble vitamins do get stored, like B12, which the body keeps in large amounts, and folate. And vitamin B6 is one of the water-soluble vitamins you can take too much of. The risk comes from high-dose supplements, never from food, and it is easy to check what you take.
What does vitamin B6 do
Vitamin B6 is a family of six related compounds. Your body turns them into two working forms, pyridoxal 5'-phosphate (PLP) and pyridoxamine 5'-phosphate (PMP), that act as helpers in more than 100 enzyme reactions. Most of those reactions are about protein: breaking it down, building it, and moving its pieces around.
B6 also helps make neurotransmitters, the brain's chemical messengers. It keeps homocysteine, an amino acid in the blood, in a normal range. It helps your body make glucose and release stored glucose, supports immune function, and helps build hemoglobin, the part of red blood cells that carries oxygen.
How much vitamin B6 do you need a day
| Group | Daily need (RDA) |
|---|---|
| Adults 19 to 50 | 1.3 mg |
| Men 51 and older | 1.7 mg |
| Women 51 and older | 1.5 mg |
| Daily Value on labels | 1.7 mg |
Most Americans get this from food. The average intake is about 1.5 mg a day for women and about 2 mg a day for men. B6 is spread across fish, poultry, beef, potatoes, chickpeas, bananas, and fortified cereal, so most people cover it without trying. About 75 percent of the B6 in a mixed diet gets absorbed.
Can you take too much vitamin B6
Yes. B6 is one of the water-soluble vitamins where too much can hurt.
When you take a large dose, your body absorbs it well and quickly sends most of it out in your urine. Most is not all. Taken in high doses every day for months, B6 can damage the sensory nerves, the ones that carry feeling.
The first clear report came in 1983, when doctors described seven adults with trouble walking and severe loss of feeling after taking high-dose pyridoxine every day. Four were severely disabled. All seven improved after they stopped (Schaumburg 1983, PMID 6308447). The classic cases involved 1 to 6 grams (1,000 to 6,000 mg) a day for 12 to 40 months, and the more people took, the worse it tended to be.
A 2023 systematic review of 20 studies reached the same conclusion: high B6 levels, usually from supplements, can cause a mostly sensory nerve damage, and people tend to improve after stopping (Muhamad 2023, PMID 37447150).
No one has been reported harmed by B6 from food.
Vitamin B6 toxicity symptoms
- Numbness, tingling, or pins and needles, often in the hands and feet
- Trouble with balance or walking (ataxia)
- Painful skin lesions and sensitivity to sunlight
- Nausea and heartburn
The nerve symptoms usually stop if the supplements stop as soon as symptoms show up, which is why catching it early matters. If you have any of these and you take B6, bring every bottle to your doctor.
What is the upper limit for vitamin B6
In the United States, the Tolerable Upper Intake Level for adults is 100 mg a day from food and supplements combined. The Food and Nutrition Board set it by looking at patients treated with about 200 mg a day for up to five years who showed no nerve damage, then halving that dose for safety. The board also noted several reports of nerve problems at doses below 500 mg a day.
In 2023, the European Food Safety Authority reviewed the research on B6 and nerve damage and set its limit at 12 mg a day for all adults.
These limits do not apply to people being treated with B6 for a medical condition under a doctor's care.
How to add up the B6 you take
The usual problem is not one bottle. It is stacking. B6 shows up in multivitamins, B-complex supplements, stand-alone B6 pills, and many products sold for energy or workouts. Between 28 and 36 percent of people take a supplement with B6 in it.
1. Line up everything you take: pills, powders, drinks, and fortified foods.
2. Find vitamin B6 on each Supplement Facts or Nutrition Facts panel. It may be listed as pyridoxine or pyridoxine hydrochloride.
3. Add the milligrams.
Plain food labels usually do not list B6 unless it was added, so you are mainly adding up supplements and fortified products.
Who is at risk of low vitamin B6
Running low on B6 alone is uncommon, and it usually comes with low B12 and folate. Groups more likely to run low:
- People with kidney disease, including people on dialysis and after a kidney transplant.
- People with rheumatoid arthritis. B6 supplements can raise the level but do not lower the inflammation.
- People with celiac disease, Crohn's disease, or ulcerative colitis.
- People with alcohol dependence, whose blood levels tend to run very low.
- People taking certain medicines, including some seizure medicines (valproic acid, carbamazepine, phenytoin), theophylline, and cycloserine. B6 can also change blood levels of some seizure medicines, so ask your doctor or pharmacist before adding any.
Signs of low B6 can include small red blood cells (microcytic anemia), scaly lips and cracks at the corners of the mouth, a swollen tongue, a skin rash, depression, confusion, and weaker immune function. A mild shortfall can show no signs for months or years.
Vitamin B6 and sideroblastic anemia
Because B6 helps build hemoglobin, it shows up in one rare inherited anemia. In X-linked sideroblastic anemia, a fault in the gene for the enzyme that starts heme production (ALAS2) leaves iron building up inside young red cells instead of becoming heme. Some people with this form respond to pyridoxine, and for them B6 is the treatment, under a specialist's care (May and Fitzsimons 1994, PMID 7881157; Morimoto 2022, PMID 34781359). It is rare and diagnosed by a hematologist. It is not a reason to take B6 for low energy.
Does vitamin B6 help your heart or memory
B6, folic acid, and B12 lower homocysteine, and high homocysteine is linked to heart disease. But most large trials found that lowering it with B vitamins did not reduce heart events. Two Norwegian trials in 6,837 people with heart disease that included a B6-only group (40 mg a day) found no benefit. A trial in 5,442 women found no effect either.
For memory and thinking, a systematic review of 14 trials found insufficient evidence that B6, alone or with B12 and folic acid, helps.
Best food sources of vitamin B6
| Food | Serving | B6 (mg) |
|---|---|---|
| Chickpeas, canned | 1 cup | 1.1 |
| Tuna, yellowfin, cooked | 3 oz | 0.9 |
| Beef liver, pan fried | 3 oz | 0.9 |
| Salmon, sockeye, cooked | 3 oz | 0.6 |
| Chicken breast, roasted | 3 oz | 0.5 |
| Potatoes, boiled | 1 cup | 0.4 |
| Banana | 1 medium | 0.4 |
| Turkey, roasted | 3 oz | 0.4 |
| Marinara sauce | 1 cup | 0.4 |
| Ground beef, 85% lean | 3 oz | 0.3 |
| Winter squash, baked | 1/2 cup | 0.2 |
| White rice, enriched | 1 cup | 0.1 |
One cup of chickpeas is most of a day by itself. Three ounces of salmon plus a banana is about 1.0 mg.
Putting it on a plate
Our Issue 018 recipe is sheet-pan salmon with crispy chickpeas, potatoes, and lemon spinach. The salmon and chickpeas alone bring about 1.4 mg of B6 per plate, a full day for most adults under 51, with no supplement in sight. Yellowfin tuna carries even more, and chicken breast works too.
The short version
- Vitamin B6 helps run more than 100 reactions, mostly in protein metabolism.
- Most adults need 1.3 mg a day, and most Americans get that from food.
- B6 is a water-soluble vitamin you can take too much of. High-dose supplements taken daily for months can damage sensory nerves.
- The US upper limit is 100 mg a day. Europe set 12 mg in 2023.
- Add up the B6 across everything you take.
- Food B6 has never been reported to cause harm. Chickpeas, fish, poultry, potatoes, and bananas are the best everyday sources.
About the evidence
This article is the evergreen companion to The Vitamin Letters, Issue 018, and draws on Anchor & Apex's curated micronutrient science (Stephanie Clarke) with fresh citation pulls by Giada. Intake targets, intake data, upper limits, risk groups, deficiency signs, trial results, and food values come from the NIH Office of Dietary Supplements vitamin B6 fact sheet (updated 2023), built on the Institute of Medicine Dietary Reference Intakes, the EFSA 2023 scientific opinion on the vitamin B6 upper limit, and USDA FoodData Central. Additional sources: the first case series of pyridoxine neuropathy (Schaumburg 1983, PMID 6308447), a systematic review of B6 and peripheral neuropathy (Muhamad 2023, PMID 37447150), and sideroblastic anemia (May and Fitzsimons 1994, PMID 7881157; Morimoto 2022, PMID 34781359). This is general education, not individualized medical or nutrition advice. Supplement decisions belong with your own clinician.
Work with Shawn. Shawn is a registered dietitian who helps people stop fighting food, whether you are leaving food rules behind, chasing a health goal, or fueling hard training. See how he works at anchorandapex.com/anchor.
Next in the series: niacin, the B vitamin behind the flush.
This article is for educational purposes and does not constitute medical advice. If this is relevant to you, please work with your physician and a registered dietitian on an individualized approach.
Be gentle with yourself out there. You are doing better than you think. ♡
Maggie Cooper
Written by Maggie Cooper · Blog & Website Copywriter · Anchor & Apex
"Smart science, soft landing. Honest words that leave you a little wiser and a lot kinder to yourself."