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Vitamin B12
A water-soluble vitamin that your liver can store for years. It helps two enzymes do their work: one turns homocysteine into methionine, the other takes part in breaking down certain fatty acids, and your body needs it to make myelin and DNA and for red blood cells to mature. It carries eight authorised EU health claims, EFSA has set no upper limit for it, and it sits in six formulas, from 10 to 500 µg.
WHAT WE ARE ALLOWED TO SAY
Eight claims. All of them authorised.
These are the wordings on the EU register for vitamin B12, and we do not paraphrase them into something that sounds stronger. All eight carry the same condition: the product has to be at least a source of vitamin B12 under Regulation (EC) 1924/2006. Our smallest dose, 10 µg, is 400% of the NRV of 2.5 µg.These are the wordings on the EU register for vitamin B12, and we do not paraphrase them. All eight need the product to be at least a source of it. Our smallest dose is 400% of the NRV.
The homocysteine claim is about normal metabolism. It is not a claim about your heart, even though our file holds a meta-analysis on homocysteine and heart disease, and we do not use it as one. Nor is B12 the headline claim where you might expect it: in B12 + folate that belongs to the B6 next to it, and in Acute energy to the vitamin C. We serve it in the morning because our notes report a slight energising effect, anecdotally. That is a timing note, not a claim.
WHY METHYLCOBALAMIN
The claims are the same. One form skips a step.
The eight claims attach to vitamin B12, not to one form of it, so the form is not a claim argument and we do not use it as one. Our file names methylcobalamin as the form of choice: it is the active form, which our file says needs no conversion, it dissolves in water and it has a neutral taste.
The cheaper form. Our notes record that it carries cyanide, and they rank methylcobalamin and hydroxocobalamin ahead of it, particularly for smokers, for advanced kidney disease and for Leber's optic atrophy.
The active form, which our file says needs no conversion. Every B12 in our six formulas is recorded as methylcobalamin. Our notes put its cost a step above cyanocobalamin.
Our form file lists light as a sensitivity, puts its best pH between 5 and 7, and does not mark it as stable in liquid. Every VION dose is a liquid, and how that is handled between production and your cartridge is not documented yet.
Our figures on how it behaves in your body are uneven. Our notes put absorption at about 50% for a small oral dose with intrinsic factor, the protein from your stomach it needs, and at 1 to 2% without it. They give a plasma half-life of about 6 days, with liver stores that last years, while our pharmacokinetic file says no half-life was found, and the two have not been reconciled yet. It takes days rather than hours to act, and it is not broken down by the CYP liver enzymes. None of this is an authorised claim, and there is no claim that methylcobalamin works better than cyanocobalamin.Our notes put its absorption at about 50% with intrinsic factor and 1 to 2% without it. Its half-life figures have not been reconciled yet. None of this is a claim.
WHERE IT APPEARS
Six of the twenty-nine carry vitamin B12.
Always methylcobalamin, always in the morning dose, and mostly 10 µg next to other B vitamins. Two formulas go higher: Acute energy at 50 µg, and B12 + folate at 500 µg, a higher dose that our ADAPT protocol runs for 12 weeks after a blood test, and then re-checks against your results. Iron is still in development, the other five are pending clinical validation, and each page lists the exclusions of its formula, where there are any.
THE CEILING
No EFSA limit. A 25 µg reference in our file.
EFSA has not set an upper limit for vitamin B12: in 2015 it found no adverse effects documented at high doses. The most conservative reference in our file is the German BfR's proposed maximum for a food supplement, 25 µg a day, and two of our formulas go above it on their own: Acute energy at 50 µg and B12 + folate at 500 µg. Our notes set a cap of 1,000 µg a day, added up across everything you take, to cover people who absorb little, such as older adults and vegetarians. That cap is not written as a rule in the engine yet. Even if all six formulas were in your plan on the same morning, your total from us would be 590 µg.EFSA has set no upper limit for vitamin B12. The German BfR reference is 25 µg a day for a supplement, and two of our formulas go above it. All six together would come to 590 µg.
In three CORE formulas and in Iron, B12 is 10 µg, 400% of the NRV. Our file records 10 µg a day as the minimum effective amount for maintenance, and EFSA's reference intake for adults is 4 µg. That is a reason to include it, not a permission to promise anything.
Our file records very few side effects: rare hypersensitivity, and occasional acne or rosacea with high doses taken for a long time. Having no upper limit is not the same as being safe at any dose, which is why the 500 µg dose runs for 12 weeks and is then checked again against your blood results.
If you take metformin or a proton pump inhibitor such as omeprazole long term, you may be at risk of low B12: talk to your doctor. Our file records no absolute contraindication for B12, and considers it safe in pregnancy and breastfeeding, under 18 at adjusted doses, and with liver, kidney or heart disease. It asks for caution with polycythaemia vera and with cancer, where high B12 levels have been linked to a worse outlook in some solid tumours, without cause and effect being established. With Leber's optic atrophy, a cobalt hypersensitivity or advanced kidney disease, our notes say to avoid cyanocobalamin; ours is methylcobalamin. The formulas that carry it add their own exclusions: Iron is ruled out with haemochromatosis, liver disease or vitamin K antagonist blood thinners; Acute energy with those blood thinners, pregnancy, breastfeeding or if you are under 18; Energy & vitality with liver disease or those blood thinners; Cognition & memory with liver disease; Stress & nervous system with liver, autoimmune, thyroid or heart disease, hyperandrogenism, sedative medication, pregnancy, breastfeeding or if you are under 18. B12 + folate lists no exclusions, but its notes ask for its folate to be watched if you carry a colorectal cancer risk with an MTHFR variant.
WHAT IT REACTS WITH
Documented pairs, not hunches.
Vitamin B12 is one of the 140 ingredients in our library, so it has 139 possible partners. Our pair table documents seven of them, out of the 443 pairs on file: four that work alongside it, and three that need care.
The two work in the same cycle, but high doses of folic acid can correct the anaemia of a B12 deficiency while nerve damage progresses silently. The engine's rule is that folate is never served without B12, and both formulas with folate carry it. Our pair notes prefer methylfolate to folic acid and set total folate at 1,000 µg a day at most.
Above 500 mg a dose, vitamin C may break down B12, though the evidence in the body is mixed and weak, so we keep them 2 hours apart: that applies to Acute immunity and Cold symptom support, which carry 1,000 mg. The 500 mg in Acute energy sits right on that line. Activated charcoal can cut how much B12 you absorb by 30 to 90%, so it never shares a dose and stays at least 3 hours away. No VION formula carries charcoal, so that matters if you take it separately.
No drug pair for B12 is in our drug table yet. Our ingredient notes list medicines that lower how much B12 you absorb: metformin, proton pump inhibitors taken for more than two years, H2 blockers such as famotidine, and colchicine. Nitrous oxide from repeated anaesthesia inactivates it, and chloramphenicol blunts your blood's response to it. If you take any of these, talk to your doctor before starting a formula that carries it.
The four pairs that work alongside it are B6 and iron, which share its formulas, and L-methionine and black garlic, which no formula carries today. Our ingredient notes add a fifth, copper, which they say is needed alongside it for red blood cells to form, but that pair is not in our pair table yet, so it is not counted above. Ginseng, caffeine, magnesium and the adaptogens it shares formulas with are not in our table as pairs with it yet. Across the library, 443 of the 9,730 possible pairs are documented, which is 4.55%. The rest are not "safe", they are simply unchecked, and we would rather write that down than let the number look like a badge.Ginseng, caffeine, magnesium and the adaptogens it shares formulas with are not in our table as pairs with it yet. Across the library, 443 of the 9,730 possible pairs are documented, which is 4.55%. The rest are not safe, they are simply unchecked.
SOURCES
Everything on this page, with its reference.
Reviewed by VION nutrition team · last reviewed 16 September 2026Read the introduction to Vitamin B12 (Cobalamin) →
140 INGREDIENTS · 64 IN USE TODAY
Every one of them has a page like this.
What it is, what we are allowed to say about it, which formulas carry it, what it reacts with and where each of those statements comes from. No proprietary blends, no hidden amounts.