What is Vitamin B6 Toxicity and What Causes it?

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

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

There are two important 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 food alone as a source of vitamin B6 does not appear to present significant risks.
• You generally have to significantly exceed the Food and Nutrition Board’s Tolerable Upper Intake Levels (ULs) to experience the toxic effects of vitamin B6.

The latter point should help ease most concerns about B6 toxicity. Additionally, the National Institutes 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 vitamin B6)
• High doses are taken daily for at least 12 months

Most vitamin B6 supplements typically contain between 50 and 100 milligrams per serving. To reach toxic levels, a person would generally need to take 10 or more doses per day consistently over an extended period.

In the unlikely event that you experience toxic levels of vitamin B6, you may develop 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 body or eye movements)^[3]
• Intense sensory neuropathy (nervous system damage)^[4]

If you reach toxic levels of vitamin B6 while taking other medications, your symptoms may vary in severity. For example^[1]:

• Combining cycloserine (an antibiotic commonly used to treat tuberculosis) with vitamin B6 supplements may increase the risk of seizures.
• Some epilepsy medications, including valproic acid, carbamazepine, and phenytoin, may cause vitamin B6 to metabolize faster than normal. Because vitamin B6 helps break down homocysteine, this interaction could lead to higher homocysteine levels in the blood, which may increase seizure risk.

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

While reaching toxic levels of vitamin B6 is uncommon, if you do experience elevated levels, stop taking vitamin B6 supplements immediately to help halt negative side effects and symptoms. More severe symptoms involving the nervous system may take longer to resolve than milder symptoms.

The National Institutes of Health notes that^[1]:

• B6 toxicity symptoms are dose-dependent – The more your vitamin B6 intake exceeds the Tolerable Upper Intake Level (UL), the more severe your symptoms may become and the longer they may take to subside.
• Toxicity symptoms typically improve on their own – In most cases, symptoms resolve after a person stops taking oral vitamin B6 supplements.

If you suspect that you’re experiencing vitamin B6 toxicity, it’s important to stop taking supplements right away. Doing so may help alleviate your symptoms and prevent them from worsening.

So, how can you make sure you’re getting enough vitamin B6 without increasing your risk of vitamin B6 toxicity? Here are a few tips:

• Incorporate food-based sources of vitamin B6 – Before turning to oral supplements, consider adding more vitamin B6-rich foods to your diet. Because vitamin B6 concentrations in food are generally low, the risk of toxicity from food sources alone is minimal.
• Be mindful of supplement dosages – If you take a vitamin B6 supplement, read the manufacturer’s label carefully before your first dose. Most importantly, avoid exceeding the Food and Nutrition Board’s recommended Tolerable Upper Intake Level (UL) for your age group.
• Talk with your healthcare provider – If you still have concerns about taking a vitamin B6 supplement or increasing vitamin B6-rich foods in your diet, speak with a healthcare provider. They can help answer your questions and recommend precautions based on your individual health needs.

While vitamin B6 toxicity is possible, it’s unlikely unless you’re taking extremely high oral doses of a vitamin B6 supplement over an extended period of time. Still, it’s a good idea to consult a healthcare provider before adding any supplement—including vitamin B6, vitamin B12, vitamin C, or vitamin D—to your routine.

With Everlywell’s vitamin B6 supplements, it’s easy to add this key nutrient to your wellness routine. You can also explore Everlywell’s full selection of vitamins and supplements to support your overall health goals.

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