A Nutrition Guide to Understanding What are the symptoms of too much vitamin B6?

October 13, 2025 •

4 min read

While vitamin B6 is essential for numerous bodily functions, excessive intake from supplements, not food sources, is the only reported cause of toxicity. Understanding what are the symptoms of too much vitamin B6 is crucial for anyone taking supplements to avoid potential nerve damage and other health complications.

Quick Summary

Excessive intake of vitamin B6, primarily from high-dose supplements, can cause a condition known as peripheral neuropathy, which leads to nerve damage. Symptoms can include numbness, tingling, pain, lack of coordination, and skin lesions. The condition often improves upon discontinuing supplements, though nerve damage can be permanent in some cases.

Key Points

Toxicity is from Supplements, not Food: Excessive vitamin B6 intake and toxicity are caused by high-dose supplements over time, not through consumption of B6-rich foods.
Peripheral Neuropathy is the Main Risk: The most significant symptom of B6 toxicity is nerve damage known as peripheral neuropathy, which affects the nerves outside the brain and spinal cord.
Key Neurological Symptoms: Common neurological signs include numbness, tingling (especially in hands and feet), loss of coordination (ataxia), and muscle weakness.
Other Side Effects: Beyond nerve damage, symptoms can include skin lesions, photosensitivity, nausea, and heartburn.
Check all Supplement Labels: Unknowingly taking multiple supplements that contain B6 is a common cause of toxicity, so it is vital to check the total dosage from all sources.
Recovery is Possible: In many cases, symptoms improve after discontinuing high-dose B6 supplements, though recovery can be slow and nerve damage can be permanent in severe instances.

Understanding Vitamin B6 Toxicity

Vitamin B6 is a crucial water-soluble vitamin involved in over 100 enzymatic reactions in the body, including metabolism and the creation of neurotransmitters. However, while dietary intake from a balanced diet is very safe, a condition called hypervitaminosis B6 can result from chronic, high-dose supplementation. This toxicity can lead to serious neurological issues, most notably a type of nerve damage called peripheral neuropathy. The precise amount of B6 intake at which symptoms appear varies widely among individuals.

Causes of Vitamin B6 Overdose

It is vital to distinguish between sources of vitamin B6 when considering toxicity. The body can effectively excrete excess B6 consumed through food, making toxicity from dietary sources extremely rare. The danger lies exclusively in over-the-counter supplements, which often contain significantly higher amounts than the body needs. Many individuals may unknowingly consume excessive amounts by taking a combination of supplements, such as a multivitamin, a B-complex formula, and a magnesium or zinc supplement, all containing pyridoxine. This makes it essential for supplement users to carefully check all labels for total B6 content.

Primary risk factors

High-dose supplementation: Taking single or multiple supplements containing high levels of vitamin B6 is the main cause of toxicity.
Long-term use: The condition often develops over a sustained period of excessive intake, rather than a single large dose.
Combined supplements: A person may unknowingly exceed safe limits by taking multiple products that each contain vitamin B6.

What are the symptoms of too much vitamin B6?

The most common and significant symptoms of vitamin B6 toxicity involve the nervous system due to peripheral neuropathy, a condition where peripheral nerves are damaged. The symptoms often begin subtly and can worsen over time with continued high intake. They can paradoxically resemble symptoms of a deficiency, making diagnosis challenging without a proper medical history of supplement usage.

Here are the key symptoms to watch for:

Numbness and tingling: A feeling of "pins and needles" or numbness, most often in the hands and feet, following a pattern known as "stocking-glove" distribution.
Painful, disfiguring skin lesions: Severe, non-specific skin problems can occur with very high amounts of B6.
Lack of coordination (ataxia): Difficulty with walking and unsteady gait due to loss of control over muscle movements.
Reduced sensation: A diminished ability to sense pain or extreme temperatures.
Muscle weakness: A general feeling of muscle weakness in the extremities.
Gastrointestinal issues: Heartburn, nausea, and stomach pain can be side effects.
Photosensitivity: An increased sensitivity of the skin to sunlight.

Comparison: Vitamin B6 Toxicity vs. Deficiency

Due to the paradoxical nature of B6 toxicity interfering with the active form of the vitamin, some symptoms can mimic deficiency. The following table highlights the key differences and similarities.


Symptom	Vitamin B6 Deficiency	Vitamin B6 Toxicity
Primary Cause	Inadequate dietary intake; certain medications; chronic illness	Chronic high-dose supplementation
Neurological Issues	Peripheral neuropathy, confusion, depression, seizures (rarely)	Peripheral neuropathy (numbness, tingling), ataxia, unsteady gait
Skin Problems	Pellagra-like syndrome: seborrheic dermatitis, glossitis, cheilosis	Painful, disfiguring skin lesions; photosensitivity
Other Effects	Anemia, weakened immune system	Nausea, heartburn, stomach pain
Onset	Gradual, chronic; often associated with other B vitamin deficiencies	Develops over a sustained period of high supplement intake

Diagnosis and Management of Toxicity

If you are taking supplements and experience any of the symptoms associated with B6 toxicity, it is important to speak with a healthcare provider. Diagnosis typically involves a comprehensive medical history, focusing on your supplement intake, and a physical examination to assess neurological function. Blood tests can measure vitamin B6 levels, and electrodiagnostic studies like an EMG may be used to confirm peripheral neuropathy.

The primary management strategy is to immediately stop taking the high-dose B6 supplement. For most people, symptoms will gradually improve once supplementation is discontinued, although recovery can be slow. In severe cases, particularly after prolonged high intake, some nerve damage may be permanent. Medical supervision is crucial during this process.

Conclusion

Vitamin B6 toxicity is a preventable condition caused by long-term, high-dose supplementation, not normal dietary intake. Recognizing what are the symptoms of too much vitamin B6, such as peripheral neuropathy, numbness, and ataxia, is essential for supplement users. The most important step to prevent toxicity is to carefully monitor your total daily supplement intake and to consult a healthcare professional before starting high-dose regimens. By prioritizing a balanced diet and being cautious with supplements, you can avoid the risks associated with excessive B6 and protect your neurological health. The Brain Foundation has published recent insights on B6 toxicity and nerve function for those interested in further research and understanding.

Frequently Asked Questions

No, it is highly unlikely to develop vitamin B6 toxicity from food sources. The condition is associated exclusively with chronic, high-dose supplementation, as the body can safely process and excrete excess B6 from diet.

The primary symptom is peripheral neuropathy, a type of nerve damage that causes symptoms like numbness, tingling, and pain, most often in the hands and feet.

High intake levels from supplements, particularly taken over a prolonged period, are associated with toxicity. However, the precise level at which symptoms appear can vary between individuals.

Yes, they can be paradoxically similar. Both can cause peripheral neuropathy and skin issues. This is because high levels of the inactive form of B6 in supplements can interfere with the body's active form, mimicking a deficiency.

If you experience symptoms of overdose, stop taking any B6 supplements immediately and consult a healthcare professional. They can review your supplement intake, conduct necessary tests, and advise on the next steps.

In many cases, the symptoms improve after discontinuing high-dose supplementation, but recovery can be slow. In some severe or long-lasting cases, the nerve damage may be permanent.

Avoid taking multiple supplements containing B6 and do not exceed recommended daily upper limits unless advised by a doctor. Always check the labels of any multivitamins or B-complex supplements you take.