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Vitamin K2
A fat-soluble vitamin that helps one enzyme do its work: activating a small group of proteins, among them the clotting factors your liver makes, osteocalcin in bone and matrix Gla protein in your blood vessels. It carries two authorised EU health claims, one for blood coagulation and one for bones, and the first is the reason no formula carrying it is ever given to someone on warfarin. EFSA has set no upper limit for it, and it sits in three formulas, at 75 or 100 µg.
WHAT WE ARE ALLOWED TO SAY
Two claims. Both of them authorised.
These are the authorised EU wordings for vitamin K, translated word for word from the Spanish text in our file, and we do not paraphrase them into something that sounds stronger. They belong to vitamin K as a whole, not to K2 alone, and both carry the same condition: the product has to be at least a source of vitamin K under Regulation (EC) 1924/2006. Our smallest dose, 75 µg, is 100% of the NRV of 75 µg.These are the authorised EU wordings for vitamin K, translated word for word from the Spanish text in our file. We do not paraphrase them. Both need the product to be at least a source of it. Our smallest dose is 100% of the NRV.
Vitamin K2 has no authorised claim for your heart or your arteries. Our file holds a meta-analysis on vitamin K and calcification of the blood vessels, and our own notes rate that evidence as preliminary, so we do not use it as one. In Cardiovascular, the heart claim belongs to the omega-3 next to it; K2 is there for normal blood coagulation. And for us that coagulation claim is mostly a reason for caution: it is why K2 stays away from anyone on warfarin or acenocoumarol.
WHY MK-7
The claims are the same. The half-life is not.
The two claims attach to vitamin K, not to one form of it, so the form is not a claim argument and we do not use it as one. Our notes name MK-7 in its trans form, made by fermentation with the natto bacterium, as the form of choice over MK-4, mainly because it stays in your body far longer: about 72 hours, against 1 to 8 hours for MK-4.
The two claims apply to it too. Our notes give it a half-life of 1.5 to 3 hours and record it as cheaper than MK-7. Our reference intakes cover vitamin K as a whole, without separating K1 from K2. It is not a form we use.
Also called menatetrenone. Our notes give it a half-life of 1 to 8 hours and record its absorption as low, against high for MK-7. In Japan it is used at 45 mg a day as a medicinal dose, far from anything we do.
The form recorded in all three of our formulas. Our form file lists it as stable in liquid, soluble in oil, neutral in taste and sensitive to light and oxygen. Our notes put its cost above K1.
Our file does not put a number on how much of it you absorb: it only says absorption is high for MK-7 and low for MK-4. It records a half-life of about 72 hours, links it to one liver enzyme, CYP4F2, and says it takes 2 to 4 weeks to act, as it builds up in your tissues. Our notes say to take it with a meal that contains fat, and all three formulas that carry it are served with dinner. None of this is an authorised claim, and there is no claim that MK-7 works better than MK-4.Our file puts no number on how much of it you absorb. It records a half-life of about 72 hours and 2 to 4 weeks to act. None of this is a claim.
WHERE IT APPEARS
Three of the twenty-nine carry vitamin K2.
Always MK-7, always in the night dose with dinner. Two of the three pair it with vitamin D3 and magnesium; the third sits it next to omega-3. All three are pending clinical validation, and all three are ruled out if you take a vitamin K antagonist such as warfarin or acenocoumarol. Each has its own exclusions, listed on its page.
THE CEILING
No EFSA limit. An 80 µg reference in our file.
EFSA has not set an upper limit for vitamin K: in 2017 it found no evidence of adverse effects at the doses studied. The most conservative reference in our file is the German BfR's proposed maximum for a food supplement, 80 µg a day. D3 / K2 goes above it on its own at 100 µg, and Cardiovascular and Bones & joints, both served at night, come to 150 µg together. Our notes set a cap of 360 µg a day, added up across everything you take, the highest supplemental dose at which our file records no blood clots. That cap is not written as a rule in the engine yet. Even if all three formulas were in your plan on the same night, your total from us would be 250 µg.EFSA has set no upper limit for vitamin K. The German BfR reference is 80 µg a day for a supplement, and D3 / K2 goes above it. All three formulas together would come to 250 µg.
Cardiovascular and Bones & joints carry 75 µg, 100% of the NRV, and D3 / K2 carries 100 µg, 133%. Our file records 180 µg a day as the minimum effective amount, the dose used in a three-year trial in healthy women after menopause, and our notes recommend 90 to 180 µg. All three of our doses are below 180 µg, and two are below 90 µg. The two claims still apply, because they only need the product to be a source of vitamin K. That is a reason to include it, not a permission to promise anything.
Our file records no significant reports of toxicity, and no blood clots at supplemental doses up to 360 µg a day. The concern is blood thinners that work against vitamin K: our file holds a study in which doses as low as 10 µg a day of MK-7 affected warfarin in some people. Having no upper limit is not the same as being safe at any dose.
Never with a vitamin K antagonist such as warfarin, acenocoumarol or phenprocoumon, whatever the reason, including an active clotting disorder or a mechanical heart valve: our notes make this an absolute contraindication, and the engine keeps every formula with K2 out of your plan. If you take any anticoagulant, including apixaban, or an antiplatelet, talk to your doctor first, as it may change their effect. Our notes ask for caution with liver disease. They consider it safe in pregnancy and breastfeeding at nutritional doses, which they put at 90 µg; D3 / K2 carries 100 µg, so ask first. They also consider it safe under 18 at the adequate intake, and with kidney disease, heart disease or cancer. Our file flags soy as a likely allergen, because MK-7 is usually made by fermenting soy, and marks it as not vegan; both still have to be checked against our supplier's sheet. The formulas that carry it add their own exclusions: D3 / K2 and Bones & joints are ruled out with high blood calcium or sarcoidosis.
WHAT IT REACTS WITH
Documented pairs, not hunches.
Vitamin K2 is one of the 140 ingredients in our library, so it has 139 possible partners. We have documented ten of them, out of the 443 pairs on file: four that work alongside it, and six that need care.
Vitamin D3 raises how much calcium you take up, and K2 activates the protein that binds it into bone. Our pair file ranks D3 with K2 as a priority combination, and when a plan carries vitamin D3, one of the engine's rules suggests keeping K2 and magnesium in it too. Magnesium is needed by the enzyme K2 works with. Bones & joints carries all four; D3 / K2 carries three.
Konjac glucomannan, psyllium husk and white clay can reduce how much K2 you absorb, so our pair file keeps them at least 2 hours apart. Activated charcoal can cut it by 30 to 90%: it never shares a dose and stays at least 3 hours away. No VION formula carries any of the four, so this matters if you take them separately. Vitamin E above 300 mg a day can work against K2; where the two meet, our file keeps vitamin E at 100 mg a day at most. The only VION formula with vitamin E carries 15 mg.
Vitamin K is a cofactor for the clotting factors that warfarin and acenocoumarol hold down, so K2 works against them and lowers your INR. Any formula carrying it is ruled out if you take one. For apixaban our drug table records a moderate interaction: keep your intake steady and check with your cardiologist at high doses, even though our notes say this class of drug is not affected by vitamin K. Our ingredient notes also list medicines that lower how much vitamin K you absorb or make: bile acid binders such as colestyramine and colestipol, orlistat, and long courses of antibiotics such as cephalosporins or ampicillin. If you take any of these, talk to your doctor before starting a formula that carries it.
Coenzyme Q10 shares Cardiovascular with it, and our file marks that pair for review: it records no restriction between the two, only that both are ruled out with warfarin, since coenzyme Q10 can lower its effect too. Manganese works alongside it in our pair file, but no VION formula carries manganese today. Our ingredient notes mention high-dose vitamin A as a mild competitor, which is not in our pair table yet, and neither are omega-3, olive hydroxytyrosol, collagen and chondroitin, which share its formulas. 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.Omega-3, olive hydroxytyrosol, collagen and chondroitin share formulas with it but 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 2026
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.