What Happens if You Have Too Much B6 in Your Blood?

November 30, 2025 •

4 min read

While vitamin B6 is essential for over 100 enzyme reactions, studies show that toxicity is caused exclusively by excessive supplement intake, not by dietary sources. This condition, known as hypervitaminosis B6, occurs when you have too much B6 in your blood, leading to a variety of adverse health effects.

Quick Summary

Taking excessive vitamin B6 supplements can cause toxicity, resulting in nerve damage called peripheral neuropathy. Symptoms include numbness, tingling, and pain in the hands and feet, along with potential muscle weakness and coordination issues. Discontinuing supplementation is the standard treatment, with recovery often taking several months.

Key Points

Cause: Vitamin B6 toxicity is caused by taking excessive amounts of supplements, not from food sources.
Primary Symptom: The most common result is peripheral neuropathy, causing nerve damage in the hands and feet.
Neurological Effects: Symptoms include numbness, tingling, pain, muscle weakness, and a lack of coordination (ataxia).
Treatment: The standard treatment is to stop taking all B6 supplements, which allows symptoms to gradually improve.
Recovery: Recovery time varies, with improvement taking several months, and some permanent nerve damage possible in severe cases.
Varying Sensitivity: Some individuals may develop symptoms at lower doses, making awareness of supplement content critical.
Safe Limits: The U.S. tolerable upper intake level for adults is 100 mg per day, though some authorities recommend lower limits.

Understanding Vitamin B6 Toxicity

Vitamin B6, or pyridoxine, is a water-soluble vitamin vital for brain function, metabolism, and immune health. However, unlike other water-soluble vitamins that are easily flushed from the body, excess B6 from supplements can accumulate and cause harm. This over-accumulation, known as hypervitaminosis B6, leads to nerve damage and other serious side effects. Cases of toxicity are virtually always linked to high-dose supplements, not a diet rich in B6-containing foods like fish, poultry, and vegetables.

The Link Between Supplements and Toxicity

Most people get enough vitamin B6 from their regular diet and do not require supplementation. However, many over-the-counter supplements, including standalone B6 products, B-complex vitamins, and even some magnesium formulas, can contain high concentrations of pyridoxine. Long-term use of these high-dose products, sometimes without the user's knowledge, is the primary cause of toxicity.

For instance, an Australian study found that some patients developed peripheral neuropathy from B6 toxicity while taking less than 50mg per day. This suggests individual sensitivity can vary, and consistent, moderate doses may still pose a risk over time. Regulatory bodies in some countries have responded by reducing the maximum daily dose permitted in supplements and requiring stronger warning labels.

Symptoms of High B6 Levels

The most common and significant symptom of too much B6 is peripheral neuropathy, which involves nerve damage in the extremities. Symptoms can range in severity and include:

Numbness and tingling: A characteristic 'pins and needles' or 'stocking-glove' sensation in the hands and feet.
Pain and burning: Sensations of pain, burning, or tingling in the affected limbs.
Ataxia: A lack of muscle control and coordination, which can cause an unsteady gait and difficulty walking.
Muscle weakness: A loss of strength, particularly in the hands and feet.
Photosensitivity: An increased sensitivity of the skin to sunlight.
Skin lesions: In some cases, painful and disfiguring skin patches have been reported.
Gastrointestinal issues: Heartburn and nausea can also occur.

Diagnosing and Treating High B6 Levels

Diagnosis typically involves a review of the patient's medical history, including all supplements being taken, followed by a neurological exam. Blood tests can also measure vitamin B6 levels, though they don't always perfectly correlate with the severity of symptoms.

Treatment is straightforward but requires patience, as the nerve damage can take time to heal. The cornerstone of treatment is:

Cessation of Supplements: Immediately stopping all supplements containing B6 is the most critical step.
Symptomatic Management: Pain medication can help manage neuropathic pain, while physical and occupational therapy may assist in regaining muscle strength and coordination.
Time and Support: For many, symptoms will improve gradually over months after discontinuing the supplement, but some permanent nerve damage can occur.

B6 Toxicity vs. Deficiency

Ironically, the symptoms of B6 toxicity can sometimes mimic those of a B6 deficiency, particularly the neurological symptoms, due to the way excess pyridoxine can inhibit the active form of the vitamin. This makes accurate diagnosis by a healthcare professional crucial. The table below compares the key distinctions.


Feature	B6 Toxicity (Hypervitaminosis B6)	B6 Deficiency
Cause	Primarily from excessive intake of supplements containing pyridoxine.	Inadequate dietary intake or impaired absorption.
Neurological Symptoms	Peripheral neuropathy, causing numbness, tingling, pain, and ataxia.	Confusion, depression, seizures (in infants), and irritability.
Non-Neurological Symptoms	Photosensitivity, painful skin lesions, nausea, and heartburn.	Skin rashes (dermatitis), inflammation of the lips and tongue, and anemia.
Blood Test Result	Elevated levels of vitamin B6.	Very low levels of vitamin B6.
Treatment	Immediately stop taking supplements.	Increase dietary B6 intake or take supplements as advised by a doctor.

Understanding Safe Limits

The tolerable upper intake level (UL) for vitamin B6 for adults is set at 100 mg per day in the U.S. and some other regions. However, some regulatory bodies and research suggest that lower doses can also lead to toxicity in susceptible individuals. It is always best to consult a healthcare provider before starting any high-dose vitamin regimen. Food-based sources of vitamin B6, such as salmon, chicken, chickpeas, bananas, and potatoes, do not pose a risk of toxicity. For those taking multiple supplements, it is especially important to read labels carefully to avoid unknowingly exceeding safe daily limits.

Conclusion

While an essential nutrient, excessive intake of supplemental vitamin B6 can have serious consequences, particularly damage to the nervous system. The key takeaway is that toxicity is caused by supplements, not food sources, and symptoms typically improve once supplementation is stopped, though recovery can be slow and sometimes incomplete. If you experience symptoms like numbness or tingling and are taking B6 supplements, consult a doctor immediately. It is crucial to be aware of the total vitamin B6 content in all your supplements to prevent this avoidable health issue.

Visit the NIH Office of Dietary Supplements for more information on vitamin B6

Frequently Asked Questions

The primary cause is the long-term, high-dose consumption of vitamin B6 from dietary supplements. Getting too much B6 from food is extremely rare.

Initial symptoms often include neurological issues such as numbness, tingling, or a burning sensation in the hands and feet. This is due to nerve damage known as peripheral neuropathy.

In most cases, symptoms of peripheral neuropathy improve after a person stops taking high-dose B6 supplements. However, recovery can be slow, and in some severe or prolonged cases, the nerve damage may be permanent.

For adults, the tolerable upper intake level is set at 100 mg per day in the U.S.. However, toxicity has been reported in individuals taking less than 50 mg per day, indicating that individual risk varies.

B-complex supplements are a common source of excess B6. Many contain doses that, when combined with other supplements or taken over time, can lead to toxicity. It is important to check the dosage on all labels.

If you experience symptoms like numbness or tingling and take B6 supplements, you should stop taking the supplements and consult a healthcare professional for a proper diagnosis and management plan.

No, there are no reported cases of B6 toxicity from dietary intake alone. The excess vitamin is efficiently processed and excreted when consumed from food.