Vitamin B6 deficiency: which symptoms point to it and which do not

17. September 2025 ca. 29 Minuten

What to expect in this article

1. What vitamin B6 actually does in the body
2. How much vitamin B6 the body needs and where the upper limit lies
3. Which symptoms have been described for vitamin B6 deficiency
4. Why a deficiency affecting only B6 is rare
5. Four steps to help you assess your suspicion
6. Who is at increased risk and why
7. The other direction: when too much vitamin B6 becomes a problem
8. Where vitamin B6 comes from in everyday life
9. What you can have measured at home for this question
10. Three ways to investigate a suspicion, compared
11. What the PLP lab result tells you and what it does not
12. Who should consider getting tested—and who should not
13. Limitations: what remains unclear about this topic
14. What matters in the end
Frequently asked questions
Sources

What vitamin B6 actually does in the body

Vitamin B6 is not a single substance, but a group. Pyridoxine, pyridoxal, and pyridoxamine are part of it, and the body converts them into the same active form: pyridoxal 5-phosphate, abbreviated as PLP. This abbreviation will matter later because it is measured in the lab.

In the cell, PLP works as a helper for enzymes. Enzymes are the tools of metabolism, and a helper is what a tool needs to engage. Without PLP, certain tools stop working, even when they are present.

The largest area of activity is protein metabolism. PLP is involved almost every time the body transforms, breaks down, or converts amino acids into one another. That is why the need for vitamin B6 increases with the amount of protein in the diet - a relationship that few other vitamins demonstrate as clearly.

Two other areas explain why the complaints described vary so much. PLP is needed to make heme, the iron-containing component of the red blood pigment. It is also needed to produce several neurotransmitters, because these messenger substances are made from amino acids.

This leads to a rule that runs through the whole article: A substance that works in so many places does not cause a typical complaint when it is in short supply. It causes many nonspecific ones. Anyone who reads a single symptom and concludes that it points to vitamin B6 is working backward, and the calculation does not work in reverse.

Why the body does not build up reserves

Vitamin B6 is water-soluble. The body excretes what it does not need through the kidneys instead of storing it. That is why intake needs to be regular, and why one generous meal cannot provide a buffer for the week.

For a long time, water solubility was seen as reassuring, even when high amounts came from supplements. That reassurance no longer holds, and the chapter on the other side explains why.

How much vitamin B6 the body needs and where the upper limit lies

Before looking at symptoms, it is worth putting the figures in context. At a glance, they show that this topic has two ends, and that they are closer together than most people expect.

The German Nutrition Society recommends an intake of 1.6 milligrams per day for adult men and 1.4 milligrams per day for adult women (based on the 2019 assessment). These values apply to all age groups from 19 onward; the recommended amounts are higher for pregnant and breastfeeding women.

At the other end is the tolerable total intake, known in technical terms as the Tolerable Upper Intake Level. It describes the amount that, from a risk assessment perspective, is not expected to cause adverse effects over a long period. In 2023, the European Food Safety Authority revised this value, lowering it for adults from 25 to 12 milligrams per day.

There is a third figure in between, and it is the most practically important. In 2024, the German Federal Institute for Risk Assessment proposed a maximum amount for food supplements: 0.9 milligrams per recommended daily serving for people aged 15 and older. This figure is deliberately below the recommended intake because a supplement is added to the diet, not a replacement for it.

Vitamin B6 in three figures

Sources: German Nutrition Society, basis for recommendations established in 2019 · European Food Safety Authority, 2023 · German Federal Institute for Risk Assessment, Opinion 008/2024

Together, these three figures tell us something none of them can tell us alone. The gap between what the body needs and what is considered safe is less than tenfold. For many other water-soluble vitamins, this gap is several times larger. Vitamin B6 has a narrow margin.

Why a maximum amount can be below the recommendation

The proposed limit of 0.9 milligrams seems contradictory at first glance. It’s below the recommended intake. The reason comes down to how it’s calculated: a maximum amount for supplements describes not what you need, but how much room remains on top of the usual intake from food without exceeding the tolerable total intake.

So if you’re wondering why a supplement containing 25 milligrams is on the shelf, you’re asking the right question. The answer is in the section about the other direction, and it’s uncomfortable.

Symptoms described in connection with vitamin B6 deficiency

The Office of Dietary Supplements at the National Institutes of Health lists the symptoms associated with vitamin B6 deficiency. The list is short and deliberately matter-of-fact. It includes microcytic anemia, abnormalities on an electroencephalogram, skin inflammation with cheilosis and glossitis, depression and confusion, and impaired immune function.

These terms need translating before they’re useful. Cheilosis refers to cracked, inflamed corners of the mouth; glossitis means a swollen, reddened tongue. Microcytic anemia is anemia in which red blood cells are smaller than usual. All three are findings diagnosed by a doctor, not sensations you can confidently interpret on your own.

What stands out on the skin and mucous membranes

Skin is a sensitive indicator of nutrient issues because it renews quickly and needs a constant supply of nutrients. A scaly, often reddened skin inflammation is described, frequently on the face and scalp. Cracked corners of the mouth and an inflamed tongue can also occur.

The catch: exactly the same symptoms are also described with iron deficiency, zinc deficiency, riboflavin deficiency, and vitamin B12 deficiency. Cracked corners of the mouth do not point to a particular vitamin. They indicate that something is wrong with overall nutrient intake - or that there is another cause entirely, such as a fungal infection.

What is described about the nervous system

Nerve symptoms are especially confusing, for a reason few guides mention. Both severe deficiency and long-term excess are associated with symptoms affecting the peripheral nerves. So tingling in the hands and feet can point in either direction.

For your own assessment, this means that taking a high-dose vitamin B supplement for tingling fingers without knowing what is causing the tingling could make things worse rather than better. This possibility belongs at the start of any consideration, not at the end.

For infants, the Office of Dietary Supplements describes a distinct set of symptoms: irritability, unusually acute hearing, and seizures. This calls for medical attention, not a self-test.

What stands out about mood and blood tests

Low mood and confusion appear in the same list. The connection makes biochemical sense because several neurotransmitters are made from amino acids, and this conversion requires PLP. But making sense does not mean it can be reversed: low mood does not imply a vitamin deficiency.

Microcytic anemia is the finding most likely to be useful because it shows up in a blood test. However, small red blood cells point to iron deficiency far more often than to vitamin B6 deficiency. Anyone with this finding should first check the most obvious possibility.

Why a deficiency affecting only B6 is rare

This section is why this article looks different from most on the subject. The Office of Dietary Supplements at the National Institutes of Health notes: “Isolated vitamin B6 deficiency is uncommon; inadequate vitamin B6 status is usually associated with low concentrations of other B-complex vitamins, such as vitamin B12 and folic acid.” In other words: isolated vitamin B6 deficiency is unusual; inadequate intake is usually associated with low concentrations of other B vitamins, such as vitamin B12 and folic acid.

This one sentence reframes the entire symptom list. If vitamin B6 deficiency almost never occurs on its own, then the question “Am I getting too little vitamin B6?” is already the wrong one. The useful question is: Is something wrong with my overall nutrient intake, and if so, what is the cause?

The difference is not a matter of wording. It determines the next step. Someone looking for a single level buys a supplement with a single ingredient. Someone asking about the pattern looks at several levels together - and is more likely to find the underlying causes that actually explain something.

There is one exception, and it is important enough to deserve its own line. Certain medications specifically affect vitamin B6 metabolism. In those cases, a largely isolated deficiency is possible. The risk chapter lists which ones.

Four steps to sort out your suspicions

The order of these four steps is not arbitrary. Each step rules out explanations that would otherwise obscure the ones that follow. These steps prepare you for a conversation with a doctor; they do not replace it.

Who is at increased risk and why

Vitamin B6 deficiency rarely has a single cause. Usually, increased use and impaired absorption occur together. The following groups are therefore not diagnoses, but reasons to take a closer look.

Impaired kidney function

People with impaired kidney function, especially those undergoing dialysis, are among the best-documented groups. The reason is clear: a water-soluble substance passes through the kidneys, and a procedure that cleans the blood removes it too. In these cases, nutritional intake is medically supervised.

Autoimmune diseases and chronic inflammation

Lower vitamin B6 levels are observed in inflammatory and autoimmune diseases. However, the direction of the relationship is not clear: the low level may be a result of the inflammation, rather than its cause. Anyone reading about this connection should understand the difference, since it determines whether supplementation would make any difference at all.

Digestive tract disorders

Chronic inflammatory bowel diseases and celiac disease interfere with nutrient absorption in the small intestine. In these cases, impaired absorption coincides with a frequently increased need. Anyone with such a diagnosis is already discussing their nutritional needs regularly with a doctor; self-testing is not the right approach.

Certain medications

Some active ingredients directly affect vitamin B6 metabolism. The best-known is an active ingredient used to treat tuberculosis, for which taking vitamin B6 alongside it is standard medical practice. Certain medications for epilepsy and inflammatory joint diseases are also mentioned in this context.

The key point is not medical, but practical: the doctor who prescribed the medication knows about these interactions. They should be discussed with them, not addressed through self-treatment.

A very one-sided diet and chronic alcohol use

Chronic alcohol use has several effects at once: it impairs absorption in the gut, speeds up breakdown, and is often accompanied by a one-sided diet. This is the situation in which supplies of several B vitamins become insufficient at the same time—and exactly the pattern described by the Office of Dietary Supplements.

The other side: when too much vitamin B6 becomes a problem

An article about vitamin B6 deficiency that leaves out this side of the issue is incomplete. People looking up deficiency symptoms usually look for a supplement right afterward—and that is where this vitamin carries the greater documented risk.

This has been known for decades. The Office of Dietary Supplements at the National Institutes of Health describes how long-term daily intake of one to six grams of pyridoxine over twelve to forty months can cause severe and progressive sensory neuropathy, characterized by ataxia—that is, loss of control over body movements. The severity depends on the dose.

These amounts in grams seem far removed from what’s in a capsule. That’s why the development over the past few years is the really interesting part: the assessment of when it becomes critical has shifted downward, not upward.

In this statement, the abbreviation NEM stands for food supplements. The figure of 0.9 milligrams is a proposal from the German Federal Institute for Risk Assessment, not a legally binding upper limit. That’s precisely why it’s informative: it describes what would be considered acceptable from a risk-assessment perspective, regardless of what is actually sold.

Why the European assessment was revised downward in 2023

In 2000, the European Commission’s Scientific Committee on Food established a tolerable total intake for vitamin B6, with the risk of peripheral sensory neuropathy in mind. This figure was 25 milligrams per day for adults.

The European Food Safety Authority reassessed this in 2023 and halved the figure to 12 milligrams per day. The endpoint remained the same: damage to the peripheral nerves. What changed was the assessment of the amount at which the risk begins.

A reduction by half is not an everyday occurrence in risk assessment. It shows that the evidence has grown in one direction, and that direction was not reassuring.

What this means in everyday life

It’s practically impossible to get too much vitamin B6 from ordinary foods. The risk comes from supplements, fortified products, and several sources adding up without you noticing: a vitamin B complex in the morning, a fortified drink in the afternoon, a protein powder after training.

We’re deliberately not giving our own dosage recommendation here. What’s right for you depends on your nutritional status, your medications, and your kidney function. A doctor knows these three things; an advice article doesn’t. What we can tell you is what figures the institutions have published, and those are listed above.

One final point that’s easy to overlook: According to the Office of Dietary Supplements, symptoms generally improve once you stop taking the supplement when neurological symptoms appear. So if you notice tingling while taking a high-dose supplement, you have a very concrete reason to talk to a doctor soon.

Where vitamin B6 comes from in everyday life

Vitamin B6 is widely distributed in the diet, and that’s the second reason why an isolated deficiency is rare. It’s found in both animal and plant foods, and there’s no single source without which nutrient intake would collapse.

Rich sources include fish, poultry and organ meats on the animal side. Plant sources include legumes, potatoes, whole grains, nuts and some vegetables. Bananas and avocados are often mentioned, but contribute less than their reputation suggests.

There are two caveats. First, vitamin B6 is heat-sensitive and water-soluble; when food is cooked for a long time, some of it passes into the cooking water. If you use the cooking water, for example in soups and stews, you lose less. Second, vitamin B6 from plant sources is partly absorbed less efficiently than from animal sources because it occurs in bound form in plants.

This doesn’t mean you need to follow a dietary prescription. It’s just a straightforward observation: if you eat a very one-sided diet, eat very little, or follow a diet without planning it carefully, there’s a good reason to look at your intake of several B vitamins together. Vitamin B12 follows its own logic, which we describe in the article on vitamin B12 deficiency – there, we discuss stores that last for years and plant-based diets; here, we’re talking about a nutrient that needs to be replenished daily.

What you can have measured at home for this question

Here comes the most honest paragraph in this article, and it reflects poorly on our own product. At mybody®x (MYBODY Lab GmbH), there is no test that measures vitamin B6.

The VitalCheck Complete is the test in the range that comes closest to answering that question. It measures 18 levels from a capillary blood sample: vitamin D3, vitamin B12 and folic acid; iron status from ferritin, iron and transferrin; calcium, magnesium, phosphate, selenium and zinc; as well as cholesterol, long-term blood sugar and CRP. Vitamin B6 is not among them. If you need a PLP measurement, you won’t get one here.

The reason this test still appears in this article has to do with the section on rarity. If vitamin B6 deficiency usually occurs alongside low levels of other B vitamins, then vitamin B12 and folic acid are the two levels that come closest to that pattern. They don’t answer the question about B6. They answer the question of whether anything is unusual about nutrient status at all.

Being open about this gap costs us this sale in some cases. Keeping it quiet would cost us something more valuable. Someone who buys a test expecting to learn their vitamin B6 level opens the results and can’t find it—and that loss of trust cannot be won back with a discount.

Anyone who actually needs a PLP test must go through a primary care practice or a laboratory with a physician’s order. The chapter on the lab value explains when this is necessary.

Three ways to investigate the concern, compared

There isn’t just one right way to answer this question, but three, each addressing a different question. The comparison shows which suits which starting point—and where each one has its limits.

The table shows one thing above all: If you’re looking exclusively for your vitamin B6 level, there’s only one route, and it requires a doctor’s order. If you want to assess your overall nutrient intake, there are three. This distinction is the whole difference between a worthwhile test purchase and a disappointing one.

What the PLP lab result does and doesn’t tell you

When vitamin B6 is measured, it’s usually measured as pyridoxal-5-phosphate in blood plasma. The Office of Dietary Supplements describes plasma PLP as the most common measure of vitamin B6 status. This wording is more cautious than it sounds: it says that this is the usual measure, not that it fully reflects the levels in body tissues.

As for the thresholds: concentrations above 30 nanomoles per liter were traditionally considered a sign of adequate levels in adults. In deriving the reference values, however, the Food and Nutrition Board used 20 nanomoles per liter as the key indicator of adequate levels.

Two different thresholds for the same question – that’s not carelessness, but the normal state of affairs in laboratory medicine. Reference ranges depend on the method, the laboratory, and the question for which the value was derived. So the figures on your own test result always matter most, not a number from an article.

There is another catch, and it affects precisely the people in whom low levels are measured most often. During inflammation, plasma PLP levels fall even when intake is adequate. A low level can then be a side effect of inflammation, not its cause. Anyone who doesn’t know the difference may supplement to correct a number that will normalize on its own once the inflammation subsides.

The same caution applies to other minerals, by the way. We have described in more detail, using magnesium and the nervous system as an example, why a blood value only ever gives a partial picture.

Who should consider testing - and who should not

Based on everything so far, the decision can honestly go either way. The right-hand column contains genuine reasons not to proceed, not merely less compelling benefits.

Limitations: what remains unclear about this topic

There are three things this article does not clarify, and they belong here in plain sight rather than in a footnote.

First: The sources reviewed here do not allow us to give a reliable figure for how widespread inadequate vitamin B6 intake is in Germany. The figures in circulation come mainly from a 2008 dietary survey and describe estimated intake from food, not measured blood levels. So we are not giving a percentage rather than presenting an old estimate as a current finding.

Second: A blood value describes a single point in time. It says nothing about what your levels were over the past six months, or about the state of your tissues. This is not a weakness of any particular provider, but a property of this measurement.

Third: Whether supplementation makes a difference in an individual case depends on causes that a measurement cannot reveal - medications, digestive tract conditions, and kidney function. A test measures and provides context. It does not treat or diagnose.

What matters in the end

People searching for vitamin B6 deficiency symptoms are usually looking for permission: permission to buy a supplement and consider the matter settled. This article doesn’t grant it, and the reason comes down to three figures. Between the recommended intake of 1.6 milligrams, the tolerable total intake of 12 milligrams, and the proposed maximum amount of 0.9 milligrams in supplements, there is a narrower range than for most other water-soluble vitamins.

This leads to something that hasn’t been stated in this article so far: with vitamin B6, doing nothing is a serious option. For most nutrient-related questions, “paying more attention” is almost always the right answer. Here, it applies in only one direction. Anyone taking high-dose supplements without a measured need is exchanging an unproven problem for a documented one.

So the specific next step isn’t to buy anything, but to check your own cupboard: What are you already taking, and how much vitamin B6 does the package list? For a surprising number of people, that one figure answers the question that brought them to this article.

And if the symptoms persist and the packaging explains nothing, the next step is to measure several levels together or consult a doctor. If you’re not sure which route is right for your question: the consultation is free, and nothing is being sold to you.

Frequently asked questions

Sources

1. German Federal Institute for Risk Assessment: 2024 update – proposed maximum levels for vitamin B6 in foods, including food supplements, Opinion 008/2024 dated February 22, 2024 – bfr.bund.de
2. European Food Safety Authority (EFSA): Scientific opinion on the tolerable upper intake level for vitamin B6, EFSA Journal 2023;21(5):8006 – efsa.onlinelibrary.wiley.com
3. German Nutrition Society: Reference Values for Nutrient Intake, Vitamin B6 (2019 derivation) – dge.de
4. National Institutes of Health, Office of Dietary Supplements: Vitamin B6 – Fact Sheet for Health Professionals (accessed 2026) – ods.od.nih.gov

The proposed maximum amount of 0.9 milligrams per recommended daily serving, the verbatim institute quotation, and the information about the Scientific Committee on Food's earlier derivation in 2000 are from [1]. The reduction of the tolerable total intake for adults from 25 to 12 milligrams per day in 2023 is reported in [1] and documented in the original source in [2]. The recommended intakes of 1.6 and 1.4 milligrams per day are from [3]. The symptom list, the statement about the rarity of an isolated deficiency, the information on plasma PLP with thresholds of 30 and 20 nanomoles per liter, and the information on sensory neuropathy at one to six grams of pyridoxine daily for twelve to forty months are from [4]. Information on price, values, sample type, and laboratory comes from the mybody®x product page, accessed on August 27, 2026; processing times follow the standard policy for blood tests. All sources were accessed and reviewed on August 27, 2026.