Nutrition Diet: What Level of B6 is Considered Toxic?

October 25, 2025 •

3 min read

While deficiency is more commonly discussed, excessive vitamin B6 intake from supplements can lead to toxicity, primarily causing neurological damage. Understanding what level of B6 is considered toxic? is crucial for preventing potentially serious, and sometimes irreversible, health issues.

Quick Summary

Excessive, long-term vitamin B6 supplementation can cause toxicity, leading to nerve damage and peripheral neuropathy. Symptoms include numbness, tingling, and poor coordination, typically linked to intake above 100 mg daily over time.

Key Points

UL for adults is 100 mg/day (US): Health authorities in the US set the Tolerable Upper Intake Level for adults at 100 mg daily, but adverse effects can occur at lower doses in some individuals over time.
Toxicity is supplement-induced: All reported cases of B6 toxicity are linked to high-dose, long-term supplementation, not dietary intake.
Peripheral neuropathy is the primary symptom: Excessive B6 damages nerves, causing numbness, tingling, pain, and loss of coordination in the hands and feet.
Recovery varies and can be slow: Symptoms often improve after discontinuing supplements, but recovery can take months or years, and in some cases, nerve damage may be permanent.
Check all supplement labels: B6 is often included in multivitamins and other supplements like magnesium, so it's important to be aware of your total daily intake from all sources.
Consult a doctor immediately if toxicity is suspected: If you experience neuropathy symptoms while taking B6 supplements, stop them at once and seek professional medical guidance.

The Dangers of Excessive Vitamin B6

Vitamin B6, also known as pyridoxine, is a water-soluble vitamin essential for numerous bodily functions, including neurotransmitter synthesis and protein metabolism. While readily available in many foods, making deficiency uncommon, high-dose supplements can accumulate in the body and lead to toxicity over time. This can particularly impact the nervous system.

Understanding the Tolerable Upper Intake Level (UL)

The Tolerable Upper Intake Level (UL) represents the maximum daily intake of a nutrient unlikely to cause adverse effects in most people. For vitamin B6, guidelines differ internationally:

US Recommendations: The UL for adults 19 and older is 100 mg per day. This is significantly higher than the recommended dietary allowance (RDA) of 1.3 mg for most adults.
European Recommendations: The EFSA sets a lower UL for adults at 12 mg/day.

While many reported toxicity cases involve doses far exceeding the UL, often over 1,000 mg daily, some individuals may experience issues at lower doses with prolonged use. Regulatory changes in Australia, for example, require warnings on products with more than 10 mg of B6 due to reports of peripheral neuropathy at intakes below 50 mg.

Symptoms of Vitamin B6 Toxicity

The most serious symptom of B6 toxicity is peripheral neuropathy, which affects nerves outside the brain and spinal cord. This can cause significant sensory and motor problems, including:

Numbness and tingling: Often starting in the hands and feet.
Pain and burning sensations: A pins-and-needles feeling in the extremities.
Ataxia: Difficulty with coordination and balance.
Muscle weakness: Reduced muscle strength.
Skin lesions: Painful skin and increased sensitivity to sunlight.
Gastrointestinal issues: Nausea and heartburn.

Interestingly, symptoms of toxicity can sometimes resemble deficiency because high doses of the supplement form (pyridoxine) can interfere with the body's use of the active form of B6.

Comparison of Daily Intake Levels vs. Toxic Intake

This table compares typical adult vitamin B6 intake levels:


Intake Type	Typical Daily Dose	Primary Source	Associated Risks
Recommended Dietary Allowance (RDA)	1.3 - 1.7 mg	Food sources (e.g., meat, fish, vegetables)	None; supports essential functions.
Tolerable Upper Intake Level (UL)	Up to 100 mg (US)	Supplements (e.g., multivitamins)	Minimal risk for most; potential risk for sensitive individuals with long-term high doses.
Toxic Doses	>100 mg, especially >1,000 mg	High-dose supplements, cumulative intake from multiple sources.	Peripheral neuropathy, nerve damage, ataxia, skin issues.

Causes of High B6 Levels

High B6 levels are overwhelmingly caused by long-term use of high-dose supplements. It is extremely difficult to reach toxic levels from diet alone. Contributing factors include:

Over-the-Counter Supplements: Taken for various conditions, often at doses well above the RDA.
Cumulative Intake: Unknowingly exceeding safe limits by taking multiple supplements containing B6.
Energy Drinks: Some are heavily fortified with B vitamins.
Underlying Conditions: Rare medical conditions can elevate B6 levels.

What to Do If You Suspect B6 Toxicity

If you suspect B6 toxicity, especially if experiencing peripheral neuropathy symptoms while taking supplements, take these steps:

Stop all B6-containing supplements immediately. Check labels for pyridoxine, pyridoxal, or pyridoxamine.
Consult a healthcare provider. They can review your history, perform exams, and may order blood tests to check B6 levels.
Manage symptoms. Supportive care like pain management and therapy may help.
Consider temporarily limiting high-B6 foods if levels are very high, such as fortified cereals, liver, and chickpeas.

Recovery and Prognosis

Recovery from vitamin B6 toxicity is often favorable after stopping supplements. However, the process can be slow, varying with the severity and duration of toxicity. In some cases, particularly with very high doses over extended periods, nerve damage may be permanent. Early detection and stopping B6 are crucial to minimize long-term issues.

Conclusion

The toxic level of vitamin B6 is typically linked to prolonged high-dose supplement use, often exceeding the US UL of 100 mg per day. Toxicity from food is extremely rare. The primary symptom is peripheral neuropathy. If taking B6 supplements, be mindful of your total daily intake. If experiencing neuropathy symptoms, stop the supplements immediately and seek medical advice.

For more information on vitamin B6, including dietary sources, consult the NIH Vitamin B6 Fact Sheet for Health Professionals.

Frequently Asked Questions

It is virtually impossible to consume a toxic level of vitamin B6 from dietary sources alone. The body can effectively regulate B6 absorption from natural foods, and toxicity is caused by the high doses found in supplements.

The initial signs of B6 toxicity often include a burning or tingling sensation, or numbness, in the hands and feet. This is an early indication of peripheral neuropathy, the most common symptom of excess B6.

For many people, nerve damage symptoms from B6 toxicity improve after they stop taking supplements, and sometimes resolve completely over several months or years. However, in some severe cases, especially after long-term, very high-dose intake, the nerve damage may be permanent.

After stopping supplementation, B6 levels begin to normalize as the body eliminates the excess. Neurological symptoms may gradually improve, but recovery can be slow, potentially taking months or even years depending on the severity and duration of the toxicity.

Yes, excessive vitamin B6 can cause ataxia, a lack of muscle control that can lead to a loss of coordination and difficulty with balance and walking. These issues are a result of the nerve damage associated with peripheral neuropathy.

The recommended dietary allowance (RDA) for most adults aged 19–50 is 1.3 mg per day. This amount is easily obtained through a balanced diet, and intake from food alone is not associated with toxicity.

While toxicity is most often linked to very high doses, individual sensitivity can vary. There is growing evidence that some individuals may experience adverse effects like neuropathy at doses lower than the US UL of 100 mg, particularly with long-term supplementation.