At a glance
A water-soluble B vitamin and coenzyme in more than a hundred metabolic reactions, especially in protein metabolism.
In Vykea: pyridoxal-5-phosphate (P5P) (8 mg per sachet)
One of the few water-soluble vitamins with an established tolerable upper intake level (12 mg per day).

Vitamin B6 is a water-soluble B vitamin. The term covers several closely related compounds that can be converted into one another in the body. As a coenzyme, vitamin B6 is involved in more than a hundred enzymatic reactions, especially in protein metabolism, the formation of messenger substances and the breakdown of homocysteine. In Omnia All-In-One we use pyridoxal-5-phosphate, the already active coenzyme form of vitamin B6 (P5P for short), at 8 mg per sachet. This entry explains the forms, food sources, functions, requirements, laboratory testing, possible signs of deficiency and interactions of vitamin B6.

The collective term vitamin B6 covers three related basic structures: pyridoxine (also called pyridoxol), pyridoxal and pyridoxamine. Each of these three compounds also occurs as a phosphate ester, i.e. as pyridoxine-5-phosphate, pyridoxal-5-phosphate and pyridoxamine-5-phosphate. Food supplements and many fortified foods traditionally use pyridoxine hydrochloride, a stable and inexpensive form.

The actual metabolically active coenzyme form of the vitamin is pyridoxal-5-phosphate (P5P). All other forms must first be converted to P5P in the body, mainly in the liver, before they can perform their tasks as a coenzyme. This conversion requires vitamin B2 (riboflavin) and zinc, among others, as helpers.

In plant foods, vitamin B6 is often present as pyridoxine glucoside, which is less available than the forms from animal foods. As a supplement, P5P is directly available as the active coenzyme form and does not need to go through the preceding conversion step. Omnia uses pyridoxal-5-phosphate.

Vitamin B6 is widely found in plant and animal foods. Good sources are wholegrain cereals and wholegrain products, pulses, potatoes and various vegetables, such as cabbage and red peppers. Among fruit, bananas and avocados in particular provide significant amounts. Among animal foods, meat (especially pork and poultry), fish such as sardines, mackerel and salmon, as well as eggs and dairy products contribute. Nuts, such as hazelnuts and walnuts, are also a good source.

Vitamin B6 is sensitive to heat and light. Significant losses can therefore occur during cooking, long storage and soaking of foods. On average, the forms from animal foods are better absorbed than the plant glucosides.

Pyridoxal-5-phosphate acts as a coenzyme in a very large number of metabolic reactions, especially in amino acid and protein metabolism:

The next section shows which of these functions are authorised as health claims.

The following health claims are authorised for vitamin B6 in the EU:

These claims apply to vitamin B6 in general and therefore also to the form used in Omnia, pyridoxal-5-phosphate.

The following values are taken from the D-A-CH reference values of the German Nutrition Society (DGE), revised in 2019, and are given in milligrams of vitamin B6 per day.

The nutrient reference value for labelling (NRV) is 1.4 mg per day. In its 2023 reassessment, the European Food Safety Authority (EFSA) gives a tolerable upper intake level of 12 mg vitamin B6 per day for adults and for pregnant and breastfeeding women. Lower values apply to children and adolescents, depending on body weight.

The requirement for vitamin B6 is closely linked to protein intake, as the vitamin is needed in amino acid metabolism. Higher requirements or poorer status can occur in the following situations: during pregnancy and breastfeeding, in older people, when absorption from the gut is impaired (for example with chronic inflammatory bowel disease), with liver or kidney disease, with regular alcohol consumption and smoking, and with a very high-protein diet. Certain medicines also increase requirements (see the Interactions section).

In people who exercise regularly or do heavy physical work, requirements may also be somewhat higher, as vitamin B6 is involved in energy and protein metabolism. In Germany, the supply to the general population through a normal mixed diet is considered satisfactory on average, but individual groups may be inadequately supplied.

Vitamin B6 does not play its role in homocysteine metabolism alone, but in interplay with folate (vitamin B9) and vitamin B12. In this metabolism, the three B vitamins serve two different but closely interlinked pathways through which the intermediate homocysteine is broken down.

In one pathway, remethylation, homocysteine is converted back into the amino acid methionine. Here, the active form of folate, 5-methyltetrahydrofolate, supplies the necessary methyl group, and vitamin B12 acts as a cofactor for the enzyme methionine synthase. In the other pathway, transsulfuration, homocysteine is broken down for good: it is converted via cystathionine to cysteine. It is precisely in this second pathway that vitamin B6, in its active coenzyme form pyridoxal-5-phosphate (P5P), plays a key role, because P5P serves as the coenzyme of the two key enzymes of transsulfuration, cystathionine beta-synthase and cystathionine gamma-lyase.

Recent scientific reviews describe the two pathways as a coordinated system: an adequate supply of all three B vitamins is the prerequisite for homocysteine to be processed via remethylation and transsulfuration. If one of the vitamins is lacking, the corresponding breakdown step can stall. For this reason, the specialist literature regards elevated homocysteine levels as a non-specific indication of a possible inadequate supply of folate, vitamin B12 or vitamin B6. These are general relationships from nutritional science at metabolic level and not a promise of effect for any individual product.

You can find more about the partner vitamins in their own entries on Folate and Vitamin B12.

Vitamin B6 status is determined by a doctor from a blood sample. The most informative laboratory value is considered to be the concentration of pyridoxal-5-phosphate (P5P) in plasma, as P5P reflects the active coenzyme form. The specialist literature regards a plasma level below about 20 nmol/l (around 5 µg/l) as an indication of inadequate supply.

Status can also be assessed indirectly via the activity of certain B6-dependent enzymes in the red blood cells, for example via the activation coefficient of aspartate aminotransferase. Elevated homocysteine levels can also indicate inadequate supply, but are not specific, as they also occur with a deficiency of folate or vitamin B12.

Note: Interpreting the values and any supplementation should be left to a doctor.

An isolated vitamin B6 deficiency is rare with a balanced diet and more often occurs together with a deficiency of other B vitamins. The signs are initially non-specific and can overlap with those of other deficiency states.

Described signs include skin changes such as inflamed, scaly redness on the face (seborrhoeic dermatitis), inflammation of the corners of the mouth and the oral mucosa, and an inflamed, reddened tongue. Neurological symptoms such as abnormal sensations, irritability, mood changes and sleep disturbances are also possible. With pronounced and longer-lasting deficiency, anaemia (microcytic anaemia) can occur, as vitamin B6 is involved in the formation of the red blood pigment. In rare cases, seizures have been described in infants with severe deficiency.

Such signs are not conclusive and can have many causes.

Note: Investigation and diagnosis should be left to a doctor.

Some medicines can lower vitamin B6 status or interact with the vitamin. These include certain tuberculosis drugs (for example isoniazid), penicillamine, hydralazine, some anti-epileptic drugs, oral contraceptives and treatment with the active ingredient levodopa for Parkinson's disease. Conversely, vitamin B6 can affect the action of some of these medicines. Vitamin B6 can also alter the availability of levodopa if it is not combined with an additional inhibitor.

Note: If you take such medicines, you should check with a doctor before taking additional vitamin B6.

In metabolism, vitamin B6 works closely with other B vitamins: folate and vitamin B12 are needed together with vitamin B6 for the breakdown of homocysteine, and vitamin B2 and zinc are involved in conversion into the active form P5P.

Vitamin B6 is water-soluble, so any excess is mainly excreted via the kidneys. Nevertheless, it is one of the few water-soluble vitamins for which a tolerable upper intake level has been set. The reason: in the scientific literature, very high doses over long periods have been associated with nerve damage, particularly sensory nerve damage in the limbs (polyneuropathy), which often regresses after intake is stopped. EFSA revised its assessment in 2023 and set the tolerable upper intake level for adults at 12 mg per day.

This upper limit applies to total vitamin B6 intake from all forms, including pyridoxal-5-phosphate (P5P). The form chosen does not change the upper limit. A daily dose of Omnia provides 8 mg of vitamin B6, which is around two thirds of the tolerable upper intake level for adults. You should therefore include vitamin B6 from other food supplements in your calculation, and do not take additional high-dose B6 supplements without consulting a doctor.

Note: Targeted or higher-dose use of vitamin B6 should be left to a doctor.

Vitamin B6 is contained in Omnia All-In-One:

The amount stated refers to the vitamin B6 content. The % of NRV is based on the labelling value of 1.4 mg. In Omnia, vitamin B6 is combined with vitamins B2 and B12 and folate, with which it works together in homocysteine metabolism and in activation to the coenzyme form. One daily dose corresponds to one sachet.

Food supplements are not a substitute for a balanced, varied diet and a healthy lifestyle.

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