Vitamin B6 is a water-soluble vitamin whose coenzyme forms take part in more than 100 enzyme reactions, mostly in protein metabolism, and support brain, blood and immune function1.
Its coenzyme forms, PLP and PMP, run more than 100 enzyme reactions, mostly in amino acid and protein metabolism1.
Needed to make neurotransmitters such as serotonin and dopamine, which plays a role in cognitive development13.
Involved in immune function, for example by promoting lymphocyte and interleukin-2 production1.
Involved in forming hemoglobin, the protein in red blood cells that carries oxygen1.
Takes part in releasing glucose from glycogen and in making new glucose (gluconeogenesis)1.
Phosphorylated food forms are split and free vitamin B6 is absorbed by passive diffusion in the jejunum1. Pyridoxal kinase turns it into PLP, which travels in plasma bound to albumin; much of the body's PLP sits in muscle bound to glycogen phosphorylase, and 4-pyridoxic acid is the main form in urine2. PLP is dephosphorylated before it enters cells3.
| Food and serving | Amount |
|---|---|
| Chickpeas, canned, 1 cup | 1.1 mg |
| Potatoes, boiled, 1 cup | 0.4 mg |
| Banana, 1 medium | 0.4 mg |
| Breakfast cereal, fortified with 25% of the DV, 1 serving | 0.4 mg |
| Marinara sauce, ready to serve, 1 cup | 0.4 mg |
| Bulgur, cooked, 1 cup | 0.2 mg |
| Cottage cheese, 1% low fat, 1 cup | 0.2 mg |
| Winter squash, baked, ½ cup | 0.2 mg |
| Food and serving | Amount |
|---|---|
| Beef liver, pan fried, 3 oz | 0.9 mg |
| Tuna, yellowfin, cooked, 3 oz | 0.9 mg |
| Salmon, sockeye, cooked, 3 oz | 0.6 mg |
| Chicken breast, roasted, 3 oz | 0.5 mg |
| Turkey, meat only, roasted, 3 oz | 0.4 mg |
| Ground beef, 85% lean, broiled, 3 oz | 0.3 mg |
About 75% of the vitamin B6 in a mixed diet is bioavailable; much of the pyridoxine in fruit, vegetables and grains is in glycosylated forms that are absorbed less well1. Amounts per serving from1.
In the U.S., adults get most of their vitamin B6 from fortified cereals, beef, poultry, starchy vegetables and some noncitrus fruits1.
Found in multivitamins, B-complex products and B6-only supplements; about 28–36% of people use a supplement that contains it1.
Much of the body's PLP is held in muscle, bound to the enzyme glycogen phosphorylase2.
The same reference table draws the reference lines on your charts in Ayuvo. Needs differ in pregnancy and breastfeeding, which are not covered here.
| Age | Women | Men | Upper limit |
|---|---|---|---|
| 19–30 | 1.3 mg | 1.3 mg | 100 mg |
| 31–50 | 1.3 mg | 1.3 mg | 100 mg |
| 51–70 | 1.5 mg | 1.7 mg | 100 mg |
| 71+ | 1.5 mg | 1.7 mg | 100 mg |
RDA (Recommended Dietary Allowance) is the daily amount that meets the needs of nearly all healthy people. Per day, for adults1.
Upper limit (UL) is the most per day that is unlikely to cause harm. Applies to food, drinks and supplements combined.
Signs like these have many possible causes. They are a reason to talk to a clinician, not to self-treat.
Isolated vitamin B6 deficiency is uncommon; low B6 usually comes with low levels of other B vitamins such as B12 and folic acid1.
Vitamin B6 from food has not been linked with harm, but long-term high-dose pyridoxine supplements can cause sensory nerve damage; nerve damage is also the basis of the 2023 European upper limit14.
Plasma PLP is the most common measure of vitamin B6 status; B6 can also be measured in red blood cells or urine, or indirectly through enzyme and tryptophan tests1.
| Plasma PLP | What it may mean |
|---|---|
| Above 30 nmol/L | Traditional sign of adequate status in adults |
| Below 20 nmol/L | Low; 20 nmol/L is the adequacy cutoff used to set the recommended amounts |
Labs use different units and ranges. Your clinician reads a result alongside your history and other tests.
Supplements most often contain pyridoxine hydrochloride, and absorption from supplements is similar to food and does not differ much between forms1.
The most common B6 form in supplements; the body absorbs large doses well but quickly removes most of it in the urine1.
The active coenzyme form, used in some supplements1.
Sold as capsules, tablets (including sublingual and chewable ones) and liquids1.
Supplements can interact with medicines. Talk to a clinician or pharmacist before you start one, especially at high doses.
Vitamin B6 from food has not been reported to cause problems. Taking high doses of pyridoxine for months or years can damage sensory nerves and affect control of body movements, and symptoms usually stop if the supplement is stopped early. In 2023 the European Food Safety Authority set a lower upper limit than the U.S. one, based on nerve damage.
Vitamin B6, folic acid and vitamin B12 can lower homocysteine, but most large trials found that B vitamin supplements did not reduce heart attacks or strokes. So far there is little evidence that vitamin B6 supplements lower cardiovascular risk.
Low vitamin B6 is more common in people with kidney disease, autoimmune conditions such as rheumatoid arthritis or celiac disease, and alcohol dependence. Some antiepileptic medicines can also lower it over time.
Food logging does not estimate vitamin B6, so Ayuvo tracks it from supplements you log in Medications, and from Apple Health on iPhone or Health Connect on Android when another app saves it there. Charts by day, week, month and year use the reference lines from this page, personalised by age and sex where they differ. Free, with no account.
Or read the code: Ayuvo is open source
Facts on this page come from these sources, checked on the dates shown. Intake numbers come from Ayuvo's shared reference table, which cites the sources marked for them.
General information, not medical advice. This guide is for healthy adults and does not cover pregnancy, breastfeeding, children or medical conditions. It cannot diagnose or treat anything. Talk to a clinician before starting high-dose supplements, or if you think you may have too little or too much of a nutrient. Spotted an error? Email us.