VIt K2 MK4 or MK7? Which is better?

I am confused about which of these formulas to take. I cannot seem to find anything definitive. I had another discussion about their effects, but I didn't ask about which is better to treat osteoporosis?

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My understanding is that if you want to keep the calcium from building up in your arteries and other organs, MK-7 is the one to take. This comes in much smaller quantites and the usual dose seems to be one 45mcg tablet, once or twice a day.

Although MK-4 may also help to protect your vessels it unfortunately has a short half life of just a couple of hrs. Whereas MK-7 last above one day, so you don't need to keep taking it throughout the day.

On the other hand if you want to take K2 as a treatment for OP, as they do in Japan, they take MK-4 at a dose of 45mg per day. Again because of the short half life, I would assume that this 45mg is split into smaller amounts throughout the day. A part from the cost, I would be wary of taking such a large quantity without my doctors approval and supervision. They don't appear to have problems with it in Japan, but their doctors are used to treating patients who take it, whereas in the UK my doctor doesn't appove of me taking either MK-4 or MK-7, because they are have not gone through the drug testing procedure, so have not been passed by NICE.

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Wasn't the MK-7 a model of photon torpedo used in the Star Trek movie to give Spock a space burial? Just kidding.

If you are already getting enough vit K in your diet, supplementation seems to be counter-intuitive. Unlike vitamin D, do we have any tests to measure your vit K levels and whether or not they are too low , too high or just right? Too much of anything good is generally bad for us. So how do we know what a safe dose of MK=7 is?

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I believe the only double blind studies on Vitamin K2 were done on K2, M4 (Menatetrenone). I think they were initially done in 1993 and 1994 by the Japanese company Eisai who then got a patent from the Ministry of Japan and it is now sold in Japan and throughout Asia under the name Glakay. I have the product from Japan and it is in 15mg tabs that are supposed to be taken three times a day. Under the name Glakay it is labeled Menatetrenone. Maybe K2, M7 is also good but I don't know if any studies have been done.

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The vitamin K found in green veg. is vitamin K1 and the body converts a SMALL quantity of this K1 into K2, but you would need to eat a vast quantity of green veg to make sufficient K2.

In the UK I don't think there are any tests to measure vit K2. Infact my GP had never even heard of it!

If you look on the Dr Mercola web site you will find information about K2 MK-7.

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Are these safe for teens? My son's endo has him on Ca and vit d3 daily but that's all. Any info out there for teens?

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Vitamin K2 in the form of MK7 is used to remove calcium from the arteries but not as good for bone strength as MK4. MK7 unclogs arteries but can cause palpitations, agitation, and in some cases muscle cramps. On the other hand, MK4 helps build bones by getting calcium into them and preventing bones from breaking down.

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Hi decana,

Thank you for starting good discussions.

I agree with LynH. The 45 mg of Mk4 is a high pharmacological dosage (typically 45 mg/day divided into multiple doses), which should NOT be taken without a doctor's supervision. For example, I am taking Mk4, but only 1 mg to 5 mg per day (one or 2 drops in the morning and 1 or 2 drops in the evening). As for Mk7, I try to get it from eating natto, 2 to 3 times per week. If I can't, I would take either Super K or LEF's low dose, but only twice per week.

In case you have not been following "Side effects of Vitamin K-2 M7 & M4?" which was initiated by you, on March 13. There are 49 useful replies now, including a table of food sources. Getting our nutrients naturally from food is the best.

Please go to ide-effects-of-vitamin-k-2-m7-and-m4/?ref=as&asat=26516153

There's also an old discussion last year which you may want to read >>> ontroversy-on-vitamin-k-either-k2-4-or-k2-7/
By nathji · July 12, 2011 at 5:21 am · 60 replies

Hi shag5,

If your son is taking Calcium and Vit. D3, it would be good to get some Vit. K2. One of the main reasons is to prevent calcification. As for safety, getting nutrients from food should be safe (unless there's certain food allergies). Pls see table referenced above. As for taking supplemental K2, it would be best to consult with the Doc, who is supposed to know your son's condition.

Hope this is helpful. Take care.

> Sylvia < < < < <

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Generally if you have serious bone loss or heart disease with artery calcification, the best for to take is the MK-4 form of Vitamin K2. This has been used in Japan since 1995 as treatment for both bone loss and heart disease. Its also the vitamin form that the human body produces for its own use. Consider the treatment level 15 mg dose three times a day primarily if you have serious medical risk of bone fracture or heart disease. Most healthy people can see progress on taking 1 mg to 5 mg of MK-4 one to three times daily along with a generous vitamin D supplement of 4000 IU to 8000 IU. The MK-4 form is shown in research to scavenge calcium from the arteries and generally help the body control its use of calcium, so it is a major positive health influence.

The MK-7 form of Vitamin K2 is also helpful but occasionally has a stimulative and heart pounding side effects that are harmless but very annoying. Typical MK-7 pills are 100 mcg while Natto has 800 mcg to 1100 mcg per serving. Much research in Japan has pointed to women having lower bone loss due to their intake of natto, so the MK-7 form is helpful but not normally produced by the human body.

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Carlson Labs also makes a K2 capsule menatetranone 15 mg. I bought mine from iHerb and it's not too spendy.


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Ooops, I mis-spoke. My Mk4 from Carlson's is only 5 mg.

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The other good thing is that these supplements help a lot of other conditions. I've had very rough skin on my knuckles for years. They often crack and bleed and are very painful, so I have to put salve on them and wear bandaids, sometimes on several fingers at once. Well the K2 I'm taking--Vitacost Ultra Vitamin K with advanced K2 Complex and Carlson's Menatetrenone (MK4)--has corrected that problem in about a week, and has also greatly improved my chronic sinus infection. And I just thought I was helping my bones! MK7 did not have those effects.

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LynnH - came across this monograph today. Very informative re the Vit-Ks - warning, long...'smile' : ig2

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After extensive reading on the Ks, I don't feel anybody has an answer as to which K is best for bones and what is a safe dosage. I think this may be discovered only in coming years. I am now (hesitantly taking 50 mcg of MKR-7 made from Natto-daily). I think that is small enough to be safe and maybe just enough to help the calcium and D get absorbed. Since the blood calcium levels don't really tell us how well the calcium is getting absorbed by the bones, I think it makes sense to take the K form that keeps calcium out of the arteries. (MKR-7): That HAS to be good for the bones.

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I think all the evidence points to the MK-4 type as being the better one. It is what we produce naturally, and all the studies show that it does good stuff that MK-7 does not. There have been no side effects even of very high doses of MK-4.

It is often stated that mk-7 is better as it stays in the blood for longer - but this actually means that your bones, organs etc are absorbing MK-4 *faster*, and preferentially.

There is a good paper here - it is by Thorne, who makes MK-4, but it cites a lot of papers comparing mk-4 and 7, and in all cases mk4 is the winner.

MK-4 is the only type that seems to have benefits for teeth - this was the original observation of Weston Price, back in the 30's (though he didn't know it was vit K2, just that "activator X" as he called it, had these beneficial effects)

You can read what some professional researchers have to say about MK-4 here: html

and here; eurological-diseases-including-parkinsons-alzheimers-and-multiple-sclerosis /

and Chris Masterjohn's great article on the Weston Price and K2;

and here; at-vitamin.html

MK-4 is the only form of K2 that is found in the brain, and it seems to offer protection against neurodegenrative diseases (alzhemiers, parkinsons, MSetc) anti-cancer properties, and improves mitochondrial functioning -which may explain the protection against MS etc, as they are mitochondrial diseases.

The high levels of MK-4 in grass fed butter and eggs, and goose liver (think foie gras) go a long way to explaining the "french paradox" of their high fat diet and low atheroscelrosis - they nail all the best sources of MK-4!

There is lots of evidence, as Chris Masterjohn writes, about the synergistic effects of the fat soluble vitamins - A, D E and K2, so make sure you are getting enough of all of them (and magnesium) - your mitochondria, especially in your brain - will thank you

And, if you wanted to know everything about K2, read the book "vit k2 and the calcium paradox" that came out last year.

wishing you best health!


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Good one Paul - excellent information. Must get that book -

Molly C

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Paul, Welcome to Inspire, and thanks for the great post!

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This just arrived in my inbox from Susan Brown at "Better bones." It's quite interesting.

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I too have just finished reading Susan Brown e mail. Very interesting.

Some time ago Dr. Cees Vermeer was interviewed by Dr. Mercola and he said then that vit K2 MK-7 was important to stop the calcium building up in the blood vessels and that it reduced the heart attack risk, linked to calcium supplements. At that time the importance of MK-7 inrelation to bones and OP wasn't mentioned. We were all pointed in the direction of MK-4 which is the routine Japanese OP treatment, as being the bone 'repair' one to take. It's good to hear that the MK-7 has also been shown to act on bones.

Although I take both at the moment, I have been thinking about stopping the MK-4 for various reasons and this article tips the scales in favour of MK-7 as far as I am concerned.

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@ Lyn H,

The Susan brown article says nothing about MK-7 being better than MK-4, it merely says that MK-7 helps prevent arterial calcification. MK-4 does this too, and you get the OP and brain benefits as a bonus.

here's a link to a study showing how MK-4 reversed calcification in rats - it will do the same in people (but we don;t do such drastic tests on people!)

Another study, on mouse arteries concluded;
"DT-diaphorase of the vitamin K-cycle, showed increased gene expression with a 4.8-fold higher specific activity in MK4 treated cells. Osteoprotegrin gene expression was down regulated and osteoprotegrin protein secretion from the MK4 treated cells was lowered 1.8-fold. These findings suggest that MK4 acts as an anti-calcification component in the vessel wall."

The key thing is that K2 activates the GLA protein in the arteries - the fact that MK-7 hangs around in the blood for 20x longer than MK-4 suggests it takes that much longer to be absorbed into GLA proteins.

You need to be careful reading these things, as the supplement makers mostly make MK-7 (from natto) as it is easier to make than MK-4. so the articles a re *very* carefully written to say how good MK-7 is, without ever directly comparing it to MK-4. I cannot find any clinical study, on rats or people, that directly compares mk4 and mk7.

You have to gather these comparisons yourself - and when you do (and I have done) you find that MK-4 seems to do everything that MK-7 does, and then some.

Better still, get your MK4 from pastured eggs, dairy and (goose/duck) pate, and cheeses, though if you truly need a therapeutic dose, then you likely need supplements. Those food sources, also contain plenty of A&D, and choline, to go with the K2. This is why I think it is better to get our nutrients from food wherever possible, there are all sorts of other good things in there, and they taste better too.

Don;t forget to make sure you are getting enough magnesium - another risk factor for atherosclerosis and calcification - most people don't.

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Hi PaulN,

Thank you for the excellent info. I agree with you that Mk4 is critical to our health -- our bones, brain, skin, teeth, etc. As indicated by the studies via your links, Mk4 has been shown to also reverse calcification. Other studies have shown Mk7 to be beneficial in preventing atherosclerosis. We can benefit by taking both Mk4 and Mk7. However, some folks have adverse side effects from taking > 90 mcg of Mk7 per day. Mk4 seems to agree with everyone, at 5 to 10 mg per day. Taking Mk4 is important if we want better bones, since Mk7 doesn't seem to do everything Mk4 does. For example, in a cellular level, the following compares mk4 and mk7.

The investigators found that Mk4 strongly activates transcription of two specific genes in osteoblast cells. The genes are GDF15 and STC2 and they’re involved in bone and cartilage formation. Their results show that Mk7 did not activate these genes. Pls see the Journal of Molecular Endocrinology

Hi LynH,

Pls think again about stopping the MK4. It offers so much. Looking at the global level, for a nation which consumes about 236,000 tons of natto every year, osteoporosis should not be a concern. However, pls see the colorful fracture map below:

Ref. FRAX map developed by J. A. Kanis et al. on behalf of International Osteoporosis Foundation (IOF) Epidemiology/Quality of Life Working Group "A systematic review of hip fracture incidence and probability of fracture worldwide" Osteoporosis International 2012.

btw, MK4 has been approved by the Ministry of Health for the prevention and treatment of osteoporosis since 1995.

Pls note that Japan is far superior to the U.S. regarding atherosclerosis mortality statistics. We are at 11%, and Japan is at 0.8% (ref. Although Mk7 cannot do everything Mk4 does, it is great for preventing and reversing calcification. Natto provides 1000 mcg of Mk7 per 100 g. Most servings are easily over 250 mcg.

In net, if we can eat natto and Foie Gras often, we'll be in good shape ;-)

Best regards,

> Sylvia < < < < < ps. PaulN, Good point about getting enough magnesium also. < < < < <

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