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What is Vitamin B6 Toxicity?
Vitamin B6 is an essential nutrient that plays a vital role in numerous bodily functions. However, excessive intake of vitamin B6, typically from supplements, can lead to a condition called peripheral neuropathy.
In 2025, there has been increasing news coverage of this issue, with reports highlighting the potential dangers of high-dose B6 supplementation and the resulting health complications.
This article is from Brain Foundation Australia
What is vitamin B6?
Vitamin B6 is a water-soluble vitamin and an essential nutrient for human function. It is needed for protein and carbohydrate metabolism, the formation of red blood cells, and certain brain cells. It also influences brain development, immune system health, and steroid hormone activity (1).
Vitamin B6 includes 6 compounds – pyridoxal, pyridoxine, pyridoxamine and their respective 5′ phosphates (2). The 5′-phosphate form of pyridoxal (PLP) is the active coenzyme form, and also the most common type of B6 found in human tissue. PLP levels are used to measure B6 blood levels in the body.
The recommended daily intake for adults is between 1.3 – 1.7mg (2). It is found in foods such as (1):
- Cereal grains
- Meat and poultry (particularly organ meats such as beef liver)
- Legumes
- Fish and shellfish
- Leafy green vegetables
- Nuts
- Fruits
Clinical deficiency is rare because most people get enough B6 from their diet. However, people who are more at risk of deficiency include those who drink excessive amounts of alcohol, women, the elderly, and people with thyroid disease (1).
Vitamin B6 in supplements
Vitamin B6 is commonly found in supplements such as multivitamins, migraine products, nerve health products, and energy drinks. Some of these are primarily B6 supplements, but many others include the vitamin as an additive. One example of this is magnesium supplements, which often include B6 because it is believed to help with magnesium absorption (although this is debated) (9,10). It may be labelled as pyridoxine, pyridoxal or pyridoxamine, depending on which form of the vitamin is included.
Most people do not need B6 supplements. As with other vitamins, it’s only necessary to take a supplement if you are deficient. Always speak to your doctor before starting any new supplements to ensure they are appropriate for you.
Understanding vitamin B6 toxicity
Vitamin B6 toxicity is associated with consuming high doses of B6 for an extended period of time. In some cases, lower doses can also cause toxicity over time. All reported cases have been linked to supplements – natural food-based sources of B6 will not cause toxicity (3,4).
Supplements containing vitamin B6 often greatly exceed the recommended daily intake, leading to a buildup of B6 in the body. The primary concern with B6 toxicity is its effect on the nervous system.
High levels of vitamin B6 can damage nerves, leading to a condition called peripheral neuropathy (3). Peripheral neuropathy happens when there is damage to the nerves located outside of the brain and spinal cord (peripheral nerves).
Symptoms & diagnosis
The main symptoms of vitamin B6 toxicity and peripheral neuropathy include (3):
- Numbness and tingling – frequently in the hands and feet, but may be present in other areas. Sometimes described as a ‘stocking-glove’ sensation.
- Difficulty walking or unsteady gait
- Pain or burning sensations
- Muscle weakness
- Loss of coordination
This list of symptoms is not exhaustive, and other less common symptoms may be present (e.g. nerve pain, cognitive changes, heart rate issues, muscle twitches and more). Further research and case studies are needed to confirm the prevalence of particular symptoms.
You should see a doctor if you experience any of these symptoms, especially if you are taking supplements containing vitamin B6. Keep in mind that vitamin B6 can be added to other supplements (such as magnesium) and is often listed by one of its chemical names – pyridoxine, pyridoxal, or pyridoxamine. It’s important to check the label of all vitamins and supplements that you’re taking.