The Daily Foundation
Vitamin B6
Vitamin B6
P5P
The unsung operator behind your body's most important chemistry. In its active form. No conversion needed. Dosed at 1.4mg every serving.
1.4mg per serving · 233µg per capsule · 6 capsules daily
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Daily Dose at 100% NRV
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Enzymatic Reactions Requiring B6
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Forms of B6. Only One is Active.
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Conversion Steps Required with P5P
What It Does
Three things. All proven.
Energy Metabolism
B6 is a required cofactor in amino acid catabolism and glycogen breakdown. Without adequate B6, your cells cannot efficiently convert stored glycogen to glucose during exercise or process amino acids for energy. It is not optional infrastructure for anyone who trains.
Neurotransmitter Synthesis
B6 as P5P is the direct cofactor in the synthesis of serotonin, dopamine, GABA, noradrenaline and histamine. Every major neurotransmitter pathway in your brain requires B6 to function. Marginal deficiency impairs mood, cognitive processing and sleep quality before any other symptoms appear.
Immune Function & Hormonal Balance
B6 is required for the proliferation and differentiation of immune cells including lymphocytes and natural killer cells. It also plays a role in steroid hormone receptor function, modulating the sensitivity of cells to hormonal signals from testosterone, oestrogen and cortisol.
The Science
The unsung operator behind your body's most important chemistry.
Vitamin B6 is a water-soluble vitamin that exists in six interconvertible forms. Of these, pyridoxal-5-phosphate, commonly written as P5P or PLP, is the biologically active coenzyme form that participates directly in enzymatic reactions. The other forms, pyridoxine, pyridoxamine and their phosphorylated variants, must be converted to P5P before they can function in the body. This conversion requires adequate liver function, zinc status and other cofactors. P5P supplementation bypasses this conversion entirely and delivers the active form directly.
The scope of B6-dependent biochemistry is extraordinary. Over 200 enzymatic reactions require B6 as a cofactor, spanning amino acid metabolism, neurotransmitter synthesis, haemoglobin production, nucleic acid metabolism and glycogen phosphorylase activity. This breadth makes B6 one of the most metabolically critical micronutrients in human physiology, yet it receives far less attention than its functional importance would suggest.
Pyridoxine HCl is the most common form used in supplements because it is cheap, stable and has a long shelf life. P5P is more expensive and less stable. The decision to use P5P in this formula reflects a commitment to bioavailability over cost. For individuals with suboptimal liver function, genetic variants in B6 metabolism, or high physiological demand, the conversion of pyridoxine to P5P is a rate-limiting step that P5P supplementation eliminates entirely.
Technically sufficient. Functionally marginal.
Most adults in developed countries consume enough B6 to avoid clinical deficiency, defined as peripheral neuropathy, dermatitis, glossitis and confirmed by blood testing. This low bar creates a misleading picture. Adequate B6 for avoiding overt deficiency and optimal B6 for peak neurotransmitter synthesis, immune function and metabolic efficiency are different thresholds.
Research using functional markers of B6 status, including plasma PLP concentration and erythrocyte alanine aminotransferase activity, consistently shows that a significant proportion of the population, particularly older adults, athletes, people with inflammatory conditions and those with high alcohol intake, has marginal B6 status that does not register as deficiency on standard assessment but measurably impairs B6-dependent pathways.
Athletes and people in regular training face elevated B6 requirements for the same reasons they face elevated requirements for many micronutrients. Protein catabolism, which is elevated in training populations, substantially increases the demand for B6 as an aminotransferase cofactor. The higher your protein intake and the harder your training, the more B6 you require above the standard reference values that were established for sedentary individuals.
Meeting the NRV is not the same as meeting the requirement of someone who trains hard, eats high protein and demands consistent cognitive output. The bar is higher than it looks.
Why B6-P5P and not pyridoxine HCl?
Pyridoxine HCl is a precursor that requires hepatic conversion to P5P before it becomes biologically active. In most healthy adults this conversion proceeds adequately. In people with reduced liver function, inflammatory conditions, genetic polymorphisms in the PNPO gene that encodes pyridox(am)ine phosphate oxidase, or simply high metabolic demand, this conversion is a meaningful rate-limiting step.
Supplementing with P5P directly provides the active coenzyme to tissues without relying on the conversion pathway. This is particularly relevant for neurotransmitter synthesis, where P5P availability in the brain is the direct rate-limiting factor for serotonin, dopamine and GABA production. Brain P5P levels respond more reliably to P5P supplementation than to equivalent doses of pyridoxine in people with conversion limitations.
There is also an important consideration around high-dose pyridoxine. At doses above 200mg per day, which is well above what is used here but present in some supplement formulations, pyridoxine can paradoxically cause peripheral neuropathy by accumulating as an antimetabolite that antagonises P5P. P5P does not carry this risk at equivalent doses. The 1.4mg P5P dose in this formula is at the NRV and involves no meaningful risk from either form, but the active form is the cleaner choice.
P5P is what your body needs. Pyridoxine is what your body has to convert. Removing that step is not a marketing claim. It is a practical improvement.
B6 is in a lot of foods. Getting enough of the right B6 is the harder question.
Vitamin B6 is broadly distributed across the food supply. Poultry, fish, pork, potatoes, bananas and chickpeas are all meaningful sources. A varied omnivorous diet typically provides 1.5 to 2mg per day, which sits around the NRV of 1.4mg. This looks adequate and for most sedentary adults eating varied whole food diets it probably is.
The practical complications arise in three ways. First, B6 in plant foods exists primarily as pyridoxine glucoside, a form with substantially lower bioavailability than the pyridoxal and pyridoxamine forms found in animal products, sometimes as much as 50% lower. Second, B6 is heat-sensitive and degrades significantly during cooking, canning and food processing. Third, as discussed, the conversion from dietary B6 forms to the active P5P is not equally efficient in all individuals.
The combination of these factors means that theoretical dietary B6 intake and functional B6 availability at the cellular level are different numbers. The 1.4mg P5P in The Daily Foundation is not designed to replace dietary B6. It is designed to ensure that at least one fully bioavailable daily dose of the active form reaches the tissues that need it, regardless of what the rest of the diet provides.
Who should take it? More people than you would expect.
01
Anyone on a high-protein diet or in regular training. Protein catabolism is B6-dependent. Higher protein intake and training volume increases B6 requirement proportionally. Standard NRV guidance was not established with high-volume athletes or high-protein dieters in mind.
02
Anyone concerned about mood, cognitive function or sleep. Serotonin, dopamine and GABA synthesis are all B6-dependent. Marginal B6 status impairs these pathways before it impairs anything else. The neurological effects of suboptimal B6 are functionally significant and frequently unrecognised.
03
Women managing hormonal health. B6 modulates steroid hormone receptor sensitivity and is involved in oestrogen metabolism. Clinical trials have used B6 at therapeutic doses for premenstrual syndrome with significant positive results. At the NRV level it supports the baseline hormonal infrastructure.
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Anyone with cardiovascular risk factors. B6 is required for homocysteine metabolism alongside B12 and folate. Elevated homocysteine is an independent cardiovascular risk factor. Adequate B6 status is a component of the methylation cycle that keeps homocysteine in check.
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Anyone eating a predominantly plant-based diet. Plant-based B6 is primarily in the glucoside form with lower bioavailability. P5P supplementation provides the active coenzyme directly without relying on conversion from less bioavailable plant-derived precursors.
Safe at 1.4mg. The high-dose caveat worth knowing.
At 1.4mg, the P5P dose in this formula is exactly at the NRV. The tolerable upper intake level for vitamin B6 supplementation, set by the European Food Safety Authority, is 25mg per day. The gap between the dose in this formula and the upper safety limit is enormous. There is no meaningful risk from peripheral neuropathy, the adverse effect associated with excessive B6 intake, at this dose.
The neuropathy risk associated with vitamin B6 supplementation has been reported almost exclusively with chronic high-dose pyridoxine supplementation in the range of 200mg to 2,000mg per day. This is 140 to 1,400 times the dose in this formula. Context matters. The risk is real at those doses but completely irrelevant to the NRV-level supplementation represented here.
P5P itself has an even cleaner high-dose safety profile than pyridoxine because it does not accumulate as an antimetabolite in the way that large amounts of pyridoxine can. At 1.4mg P5P, there is no credible safety concern in healthy adults.
1.4mg. The upper safety limit is 25mg. The neuropathy risk people have read about occurs at 200mg or more. These are not the same discussion.
At a glance
Form
Pyridoxal-5-Phosphate (P5P)
Dose Per Capsule
233µg
Daily Serving
1.4mg (6 capsules)
NRV
100%
Best Taken
With food. Consistent daily timing supports neurotransmitter rhythm.
Works With
Vitamin B12 and all other ingredients in The Daily Foundation
What the Research Shows
Immunity
B6 restriction impairs immune function within weeks. Supplementation reverses it rapidly.
Meydani et al. placed healthy elderly adults on a B6-restricted diet and documented significant reductions in lymphocyte proliferation and interleukin-2 production. B6 supplementation restored these markers to normal. The study established that even mild B6 restriction produces measurable immune impairment in a matter of weeks.
Mood
B6 supplementation produced significant improvements in PMS-related mood symptoms.
A randomised crossover trial published in the Journal of the Royal College of General Practitioners found significantly greater improvements in depression, irritability and fatigue in the B6 group versus placebo. The mechanism is serotonin and dopamine synthesis, both of which require P5P as a direct cofactor at critical steps in their production pathway.
Form
Pyridoxine HCl requires conversion. P5P does not. That distinction matters for a meaningful portion of users.
The conversion of pyridoxine HCl to P5P requires the enzyme pyridoxal kinase and pyridoxine 5-phosphate oxidase, both dependent on adequate riboflavin and zinc. Genetic variants reducing enzyme activity are common. P5P supplementation bypasses every step in this chain. It crosses the intestinal wall and is immediately available as the active coenzyme in every cell that needs it.
Homocysteine
B6 addresses elevated homocysteine through a pathway that B12 and folate cannot.
B6 converts homocysteine to cysteine via the transsulfuration pathway. B12 and folate remethylate homocysteine via a separate pathway. These two routes are complementary, not redundant. Elevated homocysteine is independently associated with cardiovascular disease, cognitive decline and all-cause mortality. Having both B6 and B12 in the same formula addresses both conversion pathways simultaneously.
Why active form
The active form costs more to produce. Every other supplement uses the inactive form. We do not.
Pyridoxine hydrochloride is inexpensive, stable and widely available. It is what 99% of B6 supplements on the market contain. It is not the form that does the work in your cells. P5P is. The cost difference between using pyridoxine HCl and P5P at 1.4mg per daily serving is negligible at a per-unit level. The decision to use P5P anyway is a formulation decision made in the interest of the consumer rather than the margin. That is what this brand is built on.
Over one hundred enzymatic reactions. One daily serving.
