How much B6 is too much in one day?

December 24, 2025 •

3 min read

The Tolerable Upper Intake Level (UL) for vitamin B6 in adults is 100 mg per day, according to the Food and Nutrition Board at the National Institutes of Health. Excessive intake from supplements, not food, is the primary cause of toxicity and potential nerve damage.

Quick Summary

Taking too much vitamin B6 from supplements can lead to toxicity, with 100 mg per day being the established upper limit for adults. High doses, particularly for extended periods, can cause peripheral neuropathy, including nerve pain, numbness, and tingling. Symptoms may improve after discontinuing supplements, but permanent damage is possible in some cases.

Key Points

Adult Upper Limit: The Tolerable Upper Intake Level (UL) for vitamin B6 in adults is 100 mg per day, primarily from supplements.
Primary Risk: Toxicity, which includes nerve damage, results from high-dose, long-term supplementation, not dietary intake.
Neurological Symptoms: Peripheral neuropathy is the most common sign of toxicity, causing tingling, numbness, pain, and loss of coordination.
Check Supplement Labels: B6 is often present in multivitamins, B-complex formulas, and magnesium supplements, so check all product labels.
Symptom Reversal: In many cases, peripheral neuropathy symptoms improve after discontinuing high-dose B6, but full recovery can be slow, and damage may sometimes be permanent.
Dietary Safety: It is virtually impossible to consume a toxic amount of B6 from food sources alone.

Understanding the Tolerable Upper Intake Level (UL)

For most healthy adults, the Tolerable Upper Intake Level (UL) for vitamin B6 is 100 mg per day. The UL represents the maximum daily intake unlikely to cause adverse health effects in the general population. While toxicity from food sources is rare, exceeding this limit via supplements can pose significant health risks. This is because the body regulates B6 from food more effectively than it does from high-dose supplements, which can lead to accumulation in the system over time.

Why Supplements are the Main Concern

Unlike dietary sources, which provide B6 in manageable, bioavailable forms, supplements often contain high concentrations of pyridoxine hydrochloride. This synthetic form can build up in the body and become toxic. Many people inadvertently take excessive amounts by combining multiple supplements, such as a multivitamin, a B-complex, and a magnesium supplement, all of which may contain B6. Recent regulatory changes in some regions, like those by the TGA in Australia, have lowered the maximum permitted daily dose in individual products and require warnings on labels for products containing more than 10mg.

Symptoms of Vitamin B6 Toxicity

The most prominent and concerning side effect of long-term, high-dose B6 supplementation is peripheral neuropathy, a type of nerve damage. Symptoms can vary in severity and may include:

Numbness and tingling: Often in a 'stocking-glove' pattern, starting in the hands and feet and moving upward.
Pain or burning sensations: Nerve damage can cause a burning or sharp, shooting pain in the extremities.
Loss of coordination: Known as ataxia, this can manifest as an unsteady gait or poor balance, making walking difficult.
Muscle weakness: A decrease in motor control can lead to muscle weakness.
Photosensitivity: In some cases, dosages above 200mg per day have been linked to increased sensitivity to sunlight, causing blistering or rashes.
Gastrointestinal issues: Symptoms such as nausea and heartburn can occur with very high doses.

Potential Reversibility and Long-Term Outlook

For many individuals, the symptoms of B6 toxicity improve once supplementation is stopped. However, recovery can be slow, sometimes taking months or even years. In certain instances, especially with very high doses taken over long periods, the nerve damage may be permanent. This underscores the importance of monitoring intake and consulting a healthcare professional.

Comparison of B6 Intake Levels


Intake Level	Effects & Associated Risks	Who Needs to Know?
Recommended Daily Allowance (RDA)	Between 1.2 and 1.7 mg for most adults. Obtained easily through diet.	All adults seeking to meet daily nutritional needs without supplementation.
Therapeutic Doses	25-100 mg/day for specific conditions (e.g., deficiency, morning sickness), but only under medical supervision.	Individuals with diagnosed conditions or those seeking treatment for specific health issues.
Upper Limit (UL) for Adults	100 mg/day. Prolonged intake at or near this level carries some risk of toxicity, though it is generally considered safe.	Supplement users who need to monitor their total daily intake from all sources.
Over 100 mg/day (Prolonged)	Increased risk of peripheral neuropathy, photosensitivity, and other side effects. Risk increases with dose and duration.	Anyone taking high-dose, single-ingredient B6 supplements or multiple B-vitamin products.
500-1000+ mg/day (Prolonged)	Substantial risk of severe peripheral neuropathy, motor control loss (ataxia), and potentially irreversible nerve damage.	Individuals taking extremely high, mega-doses of B6 supplements.

Dietary Sources vs. Supplements

It is nearly impossible to reach toxic levels of vitamin B6 through diet alone, as the body can process food-based sources efficiently. Some of the best food sources of B6 include fish, organ meats, potatoes, starchy vegetables, and non-citrus fruits. Conversely, supplements, even low-dose ones, are the typical culprits behind toxicity, especially when combined with other products containing B6. Awareness of this difference is crucial for preventing accidental overdose.

Conclusion

For adults, the safe upper limit for vitamin B6 is 100 mg per day. The risk of toxicity, primarily peripheral neuropathy, is linked to high-dose supplementation over extended periods, not to B6 from food. Common symptoms include numbness, tingling, and poor coordination, which may be reversible upon stopping the supplement, though some nerve damage can be permanent. It is essential for anyone taking multiple supplements to check labels for hidden B6 content and consult a healthcare provider to ensure their total daily intake does not exceed the safe limit. Managing B6 intake responsibly can prevent serious health complications while supporting overall well-being. For further information on recommended nutrient intakes, consult the National Institutes of Health website.

Frequently Asked Questions

For most adults aged 19–50, the RDA for vitamin B6 is 1.3 mg per day. This increases slightly for older adults and during pregnancy and lactation.

No, it is highly unlikely to get a toxic amount of vitamin B6 from food sources. The body regulates and processes B6 from dietary sources effectively.

Initial symptoms often include numbness, tingling, or a 'pins and needles' sensation, particularly in the hands and feet. This is an early sign of peripheral neuropathy.

Toxicity usually develops over a period of months to years, especially with prolonged, high-dose supplementation. It is not an acute reaction from a single high dose.

If you experience symptoms like numbness or tingling and suspect high B6 intake, stop taking the supplements and consult a healthcare professional. They can confirm the diagnosis and provide guidance.

In many cases, symptoms of peripheral neuropathy improve or resolve completely after discontinuing the high-dose B6. However, in some situations, especially with extremely high doses over long periods, the nerve damage can be permanent.

Yes, high levels of B6 can lead to a loss of muscle control and coordination, known as ataxia, which can cause an unsteady gait and poor balance.