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Home Learn Using the best form of Vitamin K: vitamin K1 vs MK-7


Using the best form of Vitamin K: vitamin K1 vs MK-7

Table of contents

What forms of vitamin K are there?

In supplements, vitamin K generally comes in the following forms:

  • Vitamin K1
  • Vitamin K2
  • Menaquinone-4 (MK-4)
  • Menaquinone-7 (MK-7)

The difference?

Vitamin K1 (phylloquinone) and vitamin K2 (menaquinone) are essentially the only two types of vitamin K. These two forms of vitamin K are significantly different from a chemical perspective, but all MK-type vitamin K supplements are derivatives of vitamin K2.

Menaquinone has a unique chemical structure with varying numbers of repeating chains at the end. Depending on how many chains menaquinone has, it is assigned a particular “MK number.” MK-4 is menaquinone with four chains, MK-7 is menaquinone with seven chains, and so on.

Due to difficulties with formulation, menaquinone and its derivatives have not been commonly used in supplements until recently. Even though stable menaquinone supplements like MK-7 have been on the market for some time now, some estimates suggest that vitamin K1 still makes up over 90% of the global vitamin K supplement supply.

However, vitamin K1 has a bioavailability score of 20% or lower, which means that the liver and organs filter out almost all of this nutrient before it can be put to any use. Supplements with low bioavailability also usually cause side effects because they put unnecessary strain on the body’s filtration mechanisms.

MK-7 and other derivatives of menaquinone are generally considered to be superior. They are more similar to the form vitamin K naturally takes in the body, which makes them more bioavailable and easier to process. Recent production advancements have made vitamin K2 supplement production affordable and reliable.


  • Vitamin K1 is not very bioavailable
  • MK-4 and MK-7 are forms of vitamin K2, which resembles the form of vitamin K that’s present   in your body

Why is vitamin K in MK-7 form better?

Your body can use any form of menaquinone with roughly the same bioavailability. The only tricky part is making sure that the vitamin K you eat is easy to convert to MK-4, which is the specific form that menaquinone takes in the body.

A study was conducted to determine the bioavailability of MK-4 and MK-7. This research found that MK-4 does not increase your tissue levels of menaquinone, but MK-7 increases your tissue levels of menaquinone in the body at nearly a 1:1 ratio. Therefore, MK-7 is a much better supplier of MK-4 than MK-4 is itself, and since all that’s necessary to change MK-7 into MK-4 is knocking off a few chains, your body can convert MK-7 into bioavailable menaquinone almost effortlessly.

Research has also been done into MK molecules with even longer chains, and it’s possible that MK-9 may have even better bioavailability than MK-7. At this stage, however, MK-7 is the most stable and bioavailable form of vitamin K on the market, and it lacks the side effects associated with vitamin K1.

Vitamin K is necessary for coagulation, and it interacts with a variety of internal organs. Overloading the body with vitamin K1 or making this vitamin hard to process could lead to dangerous bodily imbalances, and taking the most bioavailable form of vitamin K, MK-7, helps your body perform its vital functions smoothly. 


  • Vitamin K1 disrupts your bodily processes and may cause side effects
  • MK-7 seamlessly transforms into bioavailable vitamin K, helping you maintain homeostasis

Why do we use vitamin K MK-7 instead of other forms?

Vitamin K is a finicky essential nutrient. If the levels of vitamin K in your body aren’t exactly right, you might experience coagulation issues. Vitamin K1, however, throws your body out of whack with its poor bioavailability. As we researched the ingredients that would go into our Feel Multivitamin™, switching to MK-7 was an obvious choice. As we learn more about vitamin K and the best way to deliver it in your body, count on your daily Feel Multivitamin™ to evolve in tandem with the latest industry trends.

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About the author
Katie Hipwell - Katie is an AfN Registered Nutritionist (RNutr) with a specialism in food and is Head of Nutrition at Feel. Katie has worked in the food supplement industry for 10 years. She has completed a Master's degree in Human Nutrition and an undergraduate degree in BSc Sport and Exercise Nutrition.
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