What is an unsafe amount of vitamin B6 and how to avoid toxicity?

December 8, 2025 •

4 min read

According to the National Institutes of Health, while vitamin B6 deficiency is rare in the U.S., excessive intake from supplements can lead to nerve damage. This guide explains what is an unsafe amount of vitamin B6 and outlines the symptoms of toxicity to help you stay safe.

Quick Summary

Vitamin B6 toxicity typically results from long-term high-dose supplement use and can cause peripheral neuropathy. The Tolerable Upper Intake Level for adults is 100 mg daily, but adverse effects have been reported at lower supplemental doses, highlighting the need for caution. Toxicity from food sources is extremely unlikely.

Key Points

100 mg UL for adults: The Tolerable Upper Intake Level for adults is 100 mg of supplemental vitamin B6 daily, but lower doses can also cause toxicity.
Toxicity is from supplements, not food: It is nearly impossible to consume an unsafe amount of vitamin B6 from a balanced diet alone; toxicity is linked to high-dose supplement use.
Peripheral neuropathy is the main risk: The most serious side effect is nerve damage causing numbness, tingling, and poor coordination, which can become permanent.
Symptoms can mimic deficiency: In a paradoxical effect, the inactive supplemental form of B6 (pyridoxine) can interfere with the body's active form, leading to nerve damage that can present similarly to deficiency symptoms.
Regulatory limits vary internationally: While the US has a UL of 100 mg, other regions like the EU and Australia have set lower maximum daily doses, emphasizing the evolving understanding of risk.
Discontinuation is the primary treatment: The first step to manage toxicity is to stop all B6 supplements, which often leads to the resolution of symptoms, although recovery can take a long time.
Check all labels for B6: Vitamin B6 (pyridoxine) is often hidden in multivitamins, B-complexes, and other supplements, such as magnesium, and can be consumed unknowingly across multiple products.

Understanding the Tolerable Upper Intake Level (UL)

For adults aged 19 and over, the Tolerable Upper Intake Level (UL) for vitamin B6 from supplements is set at 100 milligrams (mg) per day. The UL represents the maximum daily intake of a nutrient that is unlikely to cause adverse health effects in almost all individuals in the general population. It is crucial to understand that exceeding this limit, especially through long-term supplement use, significantly increases the risk of toxicity. Unlike fat-soluble vitamins that can accumulate in the body, vitamin B6 is water-soluble, meaning any excess is typically excreted in the urine. However, excessive and prolonged supplemental intake can overwhelm the body's processing capacity, leading to toxic buildup and adverse effects, particularly on the nervous system. The form of B6 found in most supplements, pyridoxine, is thought to play a role in this toxicity by competitively inhibiting the active form of the vitamin, pyridoxal-5'-phosphate (PLP).

Symptoms and Risks of Vitamin B6 Toxicity

The most common and serious adverse effect of excessive vitamin B6 is peripheral neuropathy, which is damage to the nerves outside the brain and spinal cord.

Neurological symptoms

Numbness, tingling, or burning sensations in the hands and feet.
Difficulty walking or unsteady gait (ataxia).
Reduced ability to sense pain or temperature changes.
Muscle weakness and poor coordination.

Other possible side effects

Painful skin lesions.
Gastrointestinal issues like nausea and heartburn.
Increased sensitivity to sunlight (photosensitivity).

These symptoms can be particularly insidious because they may develop gradually and are not always immediately linked to supplement intake. While symptoms often improve after discontinuing the supplements, in severe cases of prolonged, high-dose exposure, the nerve damage can be permanent.

Comparison of B6 Intake Limits by Regulatory Body


Regulatory Body	Standard Adult Limit	Associated Risk	Notes
US Institute of Medicine	100 mg/day (UL)	Peripheral neuropathy at prolonged, high doses.	UL for adults aged 19 and older; lower limits for children.
European Food Safety Authority (EFSA)	12 mg/day (UL)	Peripheral neuropathy at doses even lower than 50 mg/day.	Reflects updated understanding that toxicity can occur at lower doses.
Therapeutic Goods Administration (TGA), Australia	100 mg/day (Max Dose)	Warning required on labels for doses over 10 mg/day.	Regulatory changes reflect new evidence of toxicity at lower doses.

Sources of Vitamin B6: Diet vs. Supplements

It is virtually impossible to reach toxic levels of vitamin B6 from food alone. The richest food sources, such as chickpeas, beef liver, and fish, contain a small fraction of the amount found in high-dose supplements. Supplemental intake, particularly chronic use of high-dose products, is the primary cause of toxicity. This is a key distinction, as many people do not realize the significant difference in concentration between food sources and supplements. Complicating matters is that some people take multiple supplements, such as a multivitamin and a magnesium complex, which can unknowingly increase their total daily intake of vitamin B6 well beyond recommended limits. Checking all supplement labels for the different chemical forms of vitamin B6 (e.g., pyridoxine hydrochloride) is essential.

What to do if you suspect vitamin B6 toxicity

If you are taking B6 supplements and experience symptoms like numbness, tingling, or an unsteady gait, it is important to take immediate action. The first step is to stop taking all supplements containing vitamin B6 and consult a healthcare professional. They can assess your symptoms, review your supplement history, and conduct blood tests to measure your vitamin B6 levels. In most cases, symptoms will improve over time after stopping the supplements, though recovery can be slow. In some instances, particularly with prolonged high-dose intake, the nerve damage may be permanent. Medical supervision is important to manage symptoms and monitor progress.

Conclusion

While vitamin B6 is an essential nutrient, excessive intake through supplements can lead to serious health problems, primarily peripheral neuropathy. The Tolerable Upper Intake Level for adults is 100 mg per day, though some international guidelines and case studies indicate potential risks at much lower doses. Toxicity from food sources is not a concern, as excessive amounts cannot be consumed through diet alone. To stay safe, it is vital to check all supplement labels for B6 content and avoid long-term use of high-dose products without medical supervision. Always consult a healthcare provider if you experience symptoms of toxicity. Being informed about the risks is the best way to prevent harm and ensure you benefit from this vital nutrient without compromising your health. For further information on the risks and regulation changes in Australia, see this report from the Therapeutic Goods Administration (TGA).

List of Food Sources for Vitamin B6

Chickpeas: Rich source, with a single cup providing over half of the daily value.
Beef Liver: Organ meats are excellent sources of B6.
Tuna and Salmon: High in B6, making them good choices for seafood lovers.
Fortified Cereals: Many breakfast cereals have added B6.
Potatoes: A cup of boiled potatoes offers a significant amount of B6.
Bananas: A convenient and popular source of the vitamin.
Poultry: Chicken and turkey are good sources.
Starchy Vegetables: Winter squash and other starchy vegetables contribute to B6 intake.

Risks of Supplementation

Supplements often contain high doses that far exceed the body's daily needs, unlike B6 found naturally in food.
The inactive form of B6, pyridoxine, commonly used in supplements, can interfere with the body's active form, leading to neurotoxic effects.
Many people are unaware they are taking B6, as it is often included in multivitamin and mineral preparations, such as magnesium supplements.
The risk of peripheral neuropathy varies by individual and can occur at daily doses well below 100 mg, making vigilance necessary even with seemingly moderate supplementation.
Prolonged high-dose use increases the severity and potential permanence of nerve damage.

Frequently Asked Questions

For adults aged 19 and older, the Tolerable Upper Intake Level for vitamin B6 is 100 mg per day from supplements. This does not include dietary intake, as food sources are not associated with toxicity.

No, it is extremely unlikely to get vitamin B6 toxicity from food sources. The amount of B6 in a varied and balanced diet is well within safe limits, and the body efficiently processes and excretes the excess.

The most common early signs are neurological symptoms, particularly peripheral neuropathy. This manifests as numbness, tingling, or a burning sensation, usually in the hands and feet.

Peripheral neuropathy is a type of nerve damage that occurs when high doses of supplemental B6 are consumed over time. It can lead to numbness, pain, and poor coordination in the extremities.

If you suspect you have toxicity, you should stop taking any supplements containing vitamin B6 immediately and consult a healthcare provider. They will evaluate your symptoms and provide guidance.

You must read the nutrition facts and ingredients list on all supplement bottles. Vitamin B6 can be listed as pyridoxine, pyridoxal, or pyridoxamine.

The prognosis depends on the severity and duration of the toxicity. While symptoms often improve or resolve after stopping supplementation, prolonged, high-dose exposure can lead to irreversible nerve damage in some cases.