Vitamin K

Forms of vitamin K

There is more than one form of vitamin K. The most used are: K1, K2 MK4 and K2 MK7. 

Vitamin K1 (phylloquinone, phytomenadione, or phytonadione) is plant derived. It is used in our bodies as a clotting factor. It is easily optained from food and is recycled by the body. Deficiencies are rare.

The vitamin K2’s that are usually meant when talking about bone strength and other things associated with calcium are K2 MK4 and K2 MK7. 

Vitamin K2 MK4 comes from animals in its natural form. In supplements it is synthetic, but exactly the same as the natural molecule. It has a short half life (meaning it doesn’t stay in the body for very long) and needs to be taken 3 times daily. K2 MK4 is called menatetrenone and also menaquinone-4.

Vitamin K2 MK7 comes from fermentation and is found in hard cheeses for instance. K2 MK7 can be taken once a day because it has a long half life. K2 MK7 is called menaquinone-7.

Both K2 MK4 and K2 MK7 can be used by our body to help shuttle calcium to the right places. K2 MK7 stays in the body longer then K2 MK4 and is a lot cheaper too. This is why people often use K2 MK7 over K2 MK4. But Weston Price did his extended research using natural K2 MK4 from whole foods.


Often the term “vitamin K” is used for either K1 or K2 MK4 or K2 MK7. But K1 and K2 have very different roles in the body. Also, a lot of sites do not distinguish between K2 MK4 and K2 MK7. But I haven’t found any studies yet to back this up. Also, the dosages for the two are very different.

Studies A two-year Japanese study found that vitamin K2 (MK-4) reduced the incidence of vertebral (spine) fractures by 52% in 120 patients with osteoporosis, compared with patients who did not receive this nutrient.

Dr. Kate Rhéaume-Bleue: Vitamin K2 and the Calcium Paradox

This video provides a very good explanation of how K2 works in the body, what foods to eat, interactions with medication, etc.
She promotes K2 MK7, because it stays in the blood way longer than K2 MK4, but MK4 is the kind that is supposed to be most natural to your body.
There’s also her book: Vitamin K2 and the Calcium Paradox. This book also promotes K2 MK7. Anything you need to know about vitamin K2 is in this book.

How much to take

(They use K2 MK7 in this site) For every increase of 10 micrograms in the amount of vitamin K2 consumed daily, the risk of developing coronary heart disease (CHD) drops by 9 percent. This statistic was noted as a result of a cohort study from the Netherlands evaluating the dietary vitamin K intakes of 16,057 post-menopausal women and their association with the incidence of CHD.  Many people/doctors seem unaware of this data.  When I see a low Vitamin D levels I usually tell the person with bad bones, a bad heart or bad teeth to increase their vitamin K2 200mcgs for every 1000 IU of D3 they are supplementing.
In the japanese study mentioned above, they used K2 MK4 in dosages of 15 mg a day (3 x 5 mg).
So K2 MK7 needs to be taken in mcg dosages, where as K2 MK4 needs to be taken in mg dosages.


There is no known toxicity for vitamin K2

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