Man in yellow shirt experiencing B6 toxicity symptoms

Vitamin B6 toxicity: what it is and what causes it

Medically reviewed on January 23, 2023 by Morgan Spicer, Medical Communications Manager. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

Table of contents - [Vitamin B6: A quick overview](#b6-overview) - [Can you take too much vitamin B6?](#can-you-take-too-much) - [What happens if your B6 is too high?](#too-high) - [Can vitamin B6 toxicity be reversed?](#reversing-toxicity) - [How to get enough B6 without risking toxicity](#get-enough-b6) - [B vitamin nutrition with Everlywell](#everlywell) - [Related content](#related)

If you’ve recently started taking a vitamin B6 supplement, or you’re adding vitamin B6-rich foods to your diet, you may have questions about vitamin B6 toxicity.

How much vitamin B6 is too much? The US Food and Nutrition Board’s published Tolerable Upper Intake Levels for Vitamin B6 state that adults over the age of 19 shouldn’t consume more than 100 mg of vitamin B6 per day (even if they’re pregnant or breastfeeding) [1].

But, what happens when you take too much vitamin B6? How can you avoid vitamin B6 toxicity in the first place? Let’s dive deeper.

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Vitamin B6: A quick overview

Vitamin B6 is a water-soluble vitamin humans need to maintain healthy bodily functions [2]. Vitamin B6 is called essential because we cannot synthesize it on our own. This means we have to consume it either in the food we eat or as a supplement. Vitamin B6 takes three main forms, each of which have a variety of functions in the body:

  • Pyridoxine
  • Pyridoxal
  • Pyridoxamine

While vitamin B6 is mostly used for protein metabolism in the body, it’s also involved in several biological processes such as [1]:

  • Amino acid metabolism
  • Neurotransmitter synthesis
  • Hemoglobin formation
  • Immune function
  • Regulation of homocysteine (a compound found in the blood)

If you eat a healthy, diverse diet filled with fruits, vegetables, fish, and legumes, you are most likely gaining a substantial amount of vitamin B6 levels through your diet. However, if you’d like to increase your B6 intake, consider adding these foods to your plate [1]:

  • Chickpeas
  • Yellowfin tuna
  • Salmon
  • Potatoes
  • Fortified breakfast cereal
  • Bananas
  • Marinara sauce
  • Cottage cheese

Can you take too much vitamin B6?

When it comes to vitamin B6 toxicity, yes, you can ingest too much vitamin B6. But the current scientific findings suggest that toxic levels are more possible through supplementation and far less possible through food.

There are two things to note about vitamin B6 toxicity [1]:

  • There are no reports in the current scientific literature of negative health impacts from eating too much vitamin B6. In other words, using only food as a source of vitamin B6 doesn’t appear to present risks.
  • You have to significantly exceed the Food and Nutrition Board’s Tolerable Upper Intake Levels (ULs) to experience the toxic effects of B6.

The latter point should ease most of your worries about B6 toxicity. Further, the National Institute of Health notes that toxicity typically only occurs when [1]:

  • Doses exceed 1 gram (1,000 milligrams) per day
  • People specifically supplement with oral pyridoxine (one specific form of B6)
  • 1+ gram doses are administered daily for at least 12 months

The typical vitamin B6 supplement dosages typically average between 50 and 100 milligrams. To reach toxic levels, you’d have to take 10+ doses per day multiple days in a row.

What happens if your B6 is too high?

In the unlikely chance that you experience toxic levels of vitamin B6, you may experience the following symptoms [1]:

  • Nausea
  • Heartburn
  • Painful skin lesions
  • Sensitivity to light
  • Numbness in the limbs [5]
  • Pain in the hands and feet [5]
  • Ataxia (loss of control over your body or eye movements) [3]
  • Intense sensory neuropathy (nervous system damage) [4]

If you reach toxic levels of B6 and are taking other medications, your symptoms may differ in severity. For example [1]:

  • Combining cycloserine (an antibiotic typically used to treat tuberculosis) with B6 supplements can cause seizures.
  • Some epilepsy drugs (e.g., valproic acid, carbamazepine, and phenytoin) can cause vitamin B6 to catalyze faster than normal. Since B6 is one of the vitamins responsible for breaking down homocysteine, this combination effect could lead to higher homocysteine concentrations in the blood, which could increase seizure risk.

If you experience any of the symptoms above, you should contact a healthcare provider right away.

Can vitamin B6 toxicity be reversed?

While reaching toxic levels of vitamin B6 is difficult to do, if you do experience high levels, stop taking vitamin B6 immediately to halt the negative vitamin B6 side effects and symptoms. The more severe symptoms involving the nervous system may take longer than the milder ones to subside.

The National Institute of Health notes that [1]:

  • B6 toxicity symptoms are dose-dependent – The more your B6 dose exceeds your UL, the worse your toxicity symptoms will be—and, potentially, the longer it will take them to subside.
  • Toxicity symptoms typically subside on their own – As long as people stop taking oral supplements as soon as they notice toxic effects, their symptoms will stop.

If you suspect that you’re experiencing B6 toxicity, it’s critical that you stop taking the supplements right away. It could be the key to alleviating your symptoms.

How to get enough B6 without risking toxicity

So, how do you make sure you’re getting enough B6 without risking vitamin B6 toxicity? Here are some tips:

  • Incorporate food-based B6 sources – Before resorting to oral supplements, consider adding more B6-rich foods to your diet. Since B6 concentrations in food are typically small, the risk of B6 toxicity through food is low.
  • Be careful with dosages – If you take an oral B6 supplement, read the manufacturer’s label before taking your first dose. Most importantly, try not to exceed the Food and Nutrition Board’s UL recommendation for your age.
  • Talk to your healthcare provider – If you still have reservations about taking a B6 supplement (or adding B6-rich foods to your diet), talk through your concerns with a healthcare provider. They may be able to provide additional information and precautions to put you at ease.

B vitamin nutrition with Everlywell

While vitamin B6 toxicity is possible, it’s unlikely unless you’re taking extremely high oral doses of a B6 supplement (10+ doses per day). That said, we recommend consulting a healthcare provider before adding any supplement (including vitamin B12, vitamin D, vitamin C, vitamin B, etc.) to your routine.

With Everlywell's vitamin B6 supplements, it's easy to get this key nutrient (as well as various other vitamins and supplements). Learn more about Everlywell's vitamin B options today.

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References

  1. Office of dietary supplements - vitamin B6. NIH Office of Dietary Supplements. URL. Published June 2, 2022. Accessed January 4, 2023.
  2. Vitamin B6: Medlineplus supplements. MedlinePlus. URL. Published April 12, 2022. Accessed January 4, 2023.
  3. Hafiz S, De Jesus O. Ataxia - statpearls - NCBI bookshelf. National Library of Medicine. URL. Published April 5, 2022. Accessed January 4, 2023.
  4. Peripheral neuropathy fact sheet. National Institute of Neurological Disorders and Stroke. URL. Published August 2018. Accessed January 4, 2023.
  5. Hemminger A, Wills BK. Vitamin B6 toxicity - statpearls - NCBI bookshelf. NIH. URL. Published April 14, 2022. Accessed January 9, 2023.
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