Vitamin K1 vs K2 - The Differences Explained

What is Vitamin k? Vitamin K1 vs. K2? What is the difference between Vitamin K1 and K2?

Vitamin K1 vs K2: What’s the Difference?

About 92% of the US population has a vitamin deficiency[1]. While many people prioritize vitamins B12, C, and D, vitamin K is too often an after-thought.

The key benefit of vitamin k resides in its ability to activate proteins responsible for three critical functions -

  1. Forming blood clots
  2. Sustaining and growing bones
  3. Preventing calcification of our arteries

If you have ever experienced major fundamental health problems, the chances are you are already aware of what vitamin k brings to the table, the fundamentals. Without vitamin k coursing through our veins, our lifespans would not be what they are today. 

Despite vitamin K1 and vitamin K2 being very different in how our bodies source, absorb, and transport the vitamins, both K1 and K2 can complete the protein activation task. It's important to know that both K1 and K2 have their strengths in terms of benefits.

In this article, we aim to address these questions -

  • What are the differences between vitamin K1 vs. K2?
  • What are the benefits of Vitamin K1?
  • What are the benefits of Vitamin K2?
  • How can you add these two vitamins to your diet?
  • Does AGN Roots Contain Vitamin K1 or K2?

    What is Vitamin K, Exactly?

    Most people associate vitamin K with three key benefits -

    1. Vitamin K helps the body form blood clots
    2. Vitamin K improves bone strength, density, and growth
    3. Vitamin K helps prevent calcium deposits from forming within your arteries

    Although vitamin K1 and K2 are both fat-soluble and share similarities in structure, they function very differently in how the body uses them. Vitamin K serves as a stand-alone supplement on over-the-counter shelves worldwide and continues to gain notoriety, especially with the elderly community looking to take full advantage of the bone density benefits. For people, ages 20 and up, the adequate intake for vitamin K is 120 mcg for men and 90 mcg for women[2].

    What is Vitamin K1, Exactly?

    Vitamin K1 is known as phylloquinone and is contained naturally within leafy-green vegetables and other plant foods.

    Phylloquinone pronounced - fi·luh·kwi·nown

    What is Vitamin K2, Exactly?

    Vitamin K2, on the other hand, is not found in leafy green plants but rather in animal products (fats) and is predominantly made by food fermentation. The bacteria in our gut produce our primary source of vitamin K2; however, the exact details of vitamin k2 synthesis from bacteria (microbiota) seem to elude many scientific studies.

    The vitamin K2 subtypes are called menaquinones (MKs), ranging from MK-4 to MK-13.

    Menaquinone pronounced - men·​a·​quin·​one

    Comparing Vitamin K1 vs. K2

    What exactly is the difference between vitamin K1 vs K2?

    Both vitamin K1 and K2 share a standard ring structure referred to as a menadione. This commonality between the vitamin k group structure is why vitamin K1 and K2 share similar metabolic pathways in their activation of the benefit-creating proteins that go to work on our bodies for the better.

    The only differentiation between vitamin k1 and k2 resides in the length and degree of saturation of the side chains called isoprenoid residues. As the isoprenoid residues grow in number, the length of the side chains grow which gives meaning to the nomenclature MK-4 to MK-13.

    Vitamin K2 MK-4 has four isoprenoid residues, whereas vitamin K2 MK-7 has seven.  These vitamin K2 structures represent the most common. 

    How is Vitamin K Absorbed?

    Vitamin K1 and K2 are absorbed into your tissues differently from one another. 

    Vitamin K1 in leafy-green form isn't absorbed by the body very efficiently at all. The body only uses a small percentage of the vitamin K1 it sources from the consumption of plants. 

    Phylloquinone is tightly bound to the plant's chloroplasts, making its bioavailability minimal. By taking vitamin K1 in its free form (oils or dietary supplements), the bioavailability can drastically improve upwards of 80%.

    When it comes to vitamin K2 absorption, the science community doesn't quite understand how the body absorbs Vitamin K2; other than that, most of it found in the body seems to come from the body's production. 

    Fun Fact: The MK-4 (vitamin K2) conversion process utilizes phylloquinone (vitamin k1) and does not involve bacteria going to work as the other versions of vitamin K2.

    How is Vitamin K Transported?

    Both Vitamin K1 and K2 end up with the liver, ultimately used in the construction of lipoproteins.

    Although K1 is likely to stay with the liver and pay most homage to the blood clotting benefits, K2 will end back into the bloodstream to carry out its work on bone health and calcium build-up prevention due to its longer side-chains.

    While your body might use K1 for a few hours (8 hours) before the body consumes the shorter vitamin half-life, K2 may linger for a few days, depending on its side-chain length. MK-13 will last longer than Mk-4, providing much more stable concentrations of K2 present in the circulating blood supply.

    Should I Take Vitamin K2 with Calcium?

    The answer is YES if you can find the right balance. By taking Vitamin K2 with calcium, it may seem like you are pulling on opposite ends of the same rope; however, by finding that sweet spot, you can capture the benefits of both 

    1. Actively fight osteoporosis with your calcium supplement
    2. Prevent the calcium from building up on the lining of your arteries with your vitamin K2 supplement

      What are the Advantages of Vitamin K2?

      As discussed above, the benefits received from Vitamin K2 result from its longer side-chains than K1. The molecular structure endemic to vitamin K2 allows for a more consistent supply of the vitamin in the bloodstream. In turn, the constant supply of Vitamin K allows for consistent activation of the matrix GLA protein (MGP), responsible for preventing vascular mineralization. In contrast to Vitamin K1, whose shorter molecular structure and therefore half-life doesn't allow for vitamin K concentrations to thrive after departing the liver.

      How Does Vitamin K2 Help Bone Growth?

      First lets run through how bones are made & repaired.  A few simple steps -

      1. The body releases calcium from our bones over time as a function of our individual metabolic needs. When the body can't replace this loss of calcium, we call this condition "Osteoporosis."
      2. The body now needs to replace this calcium loss. This process that regulates skeleton growth revolves around Osteoblasts.
      3. Osteoblasts are cells responsible for creating new bones and stem from our bone marrow. Osteoblasts produce an inactive calcium-binding protein call Osteocalcin that collects calcium from the blood.
      4. Osteocalcin, when activated, allows calcium from the blood to bind with the mineral component of our bones, creating hardened bone growth.
      5. How do we activate our Osteocalcin? You are aware of this answer already - Vitamin K2.

      Vitamin K2, when paired with newly made osteocalcin, allows the inactive osteocalcin to bind, which is how bones are grown. Osteocalcin is responsible for scavenging calcium from circulating blood flow and securing it to our bones' mineral elements. Without K2, however, the osteocalcin will remain inactive and fail to complete its mission. In a sense, this is how osteoporosis starts, bones begin to shed and break down over time, and the bones fail to regenerate at an equal rate.

      What are the Heart Health Benefits of Vitamin K?

      In May of last year (2020), the British Medical Journal published the results of an observational research study concluding that a higher intake of vitamin K2 is associated with a lower risk of coronary heart disease (CHD) and dramatically improves health outcomes [10].

      This research details that K2, not so much K1, reduced CHD risk-benefit correlation. As described in detail above, the molecular structure of K2 allows it to do a much better job of moving beyond the liver to support our other systems, such as bones and vasculature.

      What are the Bone Health Benefits of Vitamin K?

      About 54 million Americans (1 in 6) struggle with declining bone mass, a condition known as osteoporosis. Women are disproportionally impacted compared to men, with age being a significant factor. Osteoporosis occurs when the skeleton cannot regenerate bone over time while the body still naturally sheds. Consistent reduction in bone density often results in frail bones set on a path to fail[3].

      Potential risk factors include:

      • Your age (risk increases as you get older)
      • Sex (women are at higher risk)
      • Family history
      • Body frame size
      • Race
      • Too much of the thyroid hormone
      • Overactive parathyroid or adrenal gland
      • Lowered sex hormone levels
      • Low calcium intake
      • Eating disorders
      • Gastrointestinal surgery 
      • Long-term use of oral or injected corticosteroid medications
      • Medical conditions (cancer, upon, IBS, celiac disease, rheumatoid arthritis, etc.)

      If you're at risk of developing osteoporosis, talk to your doctor. They might suggest you increase your vitamin K1 and K2 intake.

      Your body needs vitamin K to activate the proteins necessary for bone growth. Low levels of both vitamins could increase your risk of bone fractures. Not only this but by ensuring you are getting enough vitamin k, you can drastically amplify your calcium intake with little fears of stiffening arteries from calcification.

      What are the Blood Clotting Benefits of Vitamin K?

      Vitamin K within our blood serves as a coenzyme for Carboxylase, the primary enzyme needed for hemostasis.

      Hemostasis is our blood's coagulation process; coagulation is a term that describes our blood transforming from a flowing liquid to a slow-moving gel. In a state where a physiological response is warranted to prevent further hemorrhaging, vitamin K can come to the rescue.

      There are patients with blood clotting disorders who require medication like warfarin (anticoagulant). These medications keep the blood from clotting too quickly. Whether you should continue supplementing vitamin K while taking blood thinners or anticoagulants is entirely up to you and your doctor.

      Vitamin K1 vs. K2 in Your Diet

      Remember, women should get about 90 mcg of vitamin K a day, while men should get 120 mcg/day. You can add vitamin K to your diet with a mix of leafy greens and animal products.

      You can add a fat source to your meal to improve vitamin K2 absorption. Try using egg yolks or olive oil to make it easier for your body to absorb the vitamin.

      Make sure to speak with your doctor before making any significant changes to your diet. If you are curious to know your current vitamin k levels, blood work is an available option.

      What is the Daily Recommended Dosage of Vitamin K?

      The answer to this question is dependent on both gender and life stage.

      The average daily recommended quantity of Vitamin k is as follows - 

      Age Ranges Recommended Amount (mcg)
      < 6 months 2.0 micrograms
      7 to 12 months 2.5 micrograms
      1 to 3 years 30 micrograms
      4 to 8 years 55 micrograms
      9 to 13 years 60 micrograms
      14 - 18 years 75 micrograms
      > 19 years (Men) 120 micrograms
      > 19 years (Women) 90 micrograms
      Lactating or Pregnant Adults 90 micrograms

      Vitamin K1

      Remember, vitamin K1 is produced by plants, including leafy greens. In fact, K1 plays a role in stimulating the photosynthesis reaction in plants, which is why it's found in the leaves of plants. 

      A few food sources of K1 include:

      • Kale
      • Spinach
      • Turnip greens
      • Collard greens
      • Brussels sprouts
      • Broccoli

      What Foods Contain Vitamin K2?

      Vitamin K2 is mostly microbial. The food source can differ based on the subtype. Below is a table to summarize: 

       Vitamin K2 Subtype Food Sources Containing Vitamin K2
      MK-4 Sauerkraut, Natto (fermented beans), Cheese (hard & soft), eggs, whole milk
      MK-5 Sauerkraut, Natto (fermented beans), Cheese (edam, curd cheese), whole milk
      MK-7 Sauerkraut, Natto (fermented beans), Cheese - Blue cheese, Cheddar, Leicester, Butter Milk
      MK-8 Sauerkraut, Natto (fermented beans), Cheese - Blue cheese, Caerphilly, Cheddar, Leicester, Cheshire, Butter Milk
      MK-9 Sauerkraut, Natto (fermented beans), Cheese - Blue cheese, Caerphilly, Cheddar, Leicester, Cheshire, Appenzeller, Comte, Emmental, Jarlsberg, Raclette, Butter Milk
      MK-10 Cheese - Blue cheese, Cheddar, Leicester, Cheshire, Edam, Emmental
      MK-11 Full fat dairy products


      Does AGN Roots Grass-Fed Whey Contain Vitamin K2?

      Yes, AGN Roots Grass-Fed Whey contains a healthy serving of vitamin k (K2) as a proportion of the fat  in the product which is little to nothing. There is .232 micro-grams of vitamin k2 in every serving of AGN Roots Grass-Fed Whey Isolate.

      Vitamin K Deficiency

      About 8 to 31% of adults have a vitamin K deficiency. Vitamin K deficiency can cause significant bleeding, cardiovascular disease, poor bone development, and osteoporosis[9].

      While vitamin K deficiency is rare, it can occur if you have severe malabsorption or malnutrition. It's common with patients who take warfarin as well.

      Fat malabsorption occurs when your body struggles to absorb fat. Some medical conditions can cause malabsorption, which can increase your chance of deficiency.

      These conditions include:

      • An intestinal or biliary tract disorder (bile duct, gallbladder, liver)
      • Cystic fibrosis
      • Celiac disease

      Bariatric surgery or having part of your intestine removed can increase your risk, too.

      Some newborn babies can also develop vitamin K deficiency.

      This often occurs when their mother's breast milk doesn't contain adequate levels of vitamin K. It's possible their liver is unable to use the vitamin, too.

      Your risk of vitamin K deficiency could increase if you currently take anticoagulants or blood thinners. These can inhibit vitamin K activation while preventing blood clots.

      Are you taking any medications, such as antibiotics, that interfere with vitamin K production? Speak with your doctor. They might want to switch you to a different medication.

      You can also develop a deficiency if you're taking high doses of vitamin A and E.

      Learn More Here: Best Whey Protein for Bariatric Surgery

      What are the Symptoms of Vitamin K2 Deficiency?

      If you have a vitamin K deficiency, you might experience symptoms like:

      • Excessive bleeding
      • Bruising easily
      • Stool that appears black or contains blood
      • Bleeding in mucous membranes
      • Small blood clots underneath the fingernails

      You might not experience these symptoms unless you're accidentally cut. 

      If you're pregnant, your doctor can look for signs of a vitamin K deficiency in your newborn or infant.

      These symptoms can include bleeding:

      • If the baby is circumcised
      • From where the umbilical cord was removed
      • In the nose, skin, gastrointestinal tract, or other areas
      • Sudden brain bleeds
      • Sudden brain bleeds are potentially life-threatening.

      If you have a vitamin K deficiency, your doctor will perform a coagulation test. They'll take a blood sample, then determine how long it takes to clot. If your blood takes longer than 13.5 seconds, you might have a deficiency.

      Vitamin K1 vs K2 Recap -

      What's the difference between vitamin K1 vs. K2?

      The differences lie in how they're absorbed and transported. The potential health benefits they can offer differ as well. Regardless of their differences, you need both vitamins to improve your health and wellbeing.

      Want to add more vitamin K to your diet? Consider using grass-fed whey protein as a smoothie base.  Add a little whole dairy like organic ice cream and some greens :) 

      Check out our latest grass-fed whey recipes today to help you get more Vitamin K2 in your diet. 

      [1] Bloom, Martin G. “92% Of U.S. Population Have Vitamin Deficiency. Are You One of Them?The Biostation, 2021,,Americans%20are%20vitamin%20D%20deficient.
      [2] Health, National Institute of. “Office of Dietary Supplements - Vitamin K.” NIH Office of Dietary Supplements, U.S. Department of Health and Human Services, 3 July 2020,
      [3] Foundation, National Osteoporosis. “General Facts.National Osteoporosis Foundation - General Facts, 16 Feb. 2021,
      [4] Media, Cns. “Demands for Vitamin K2 RDI as Study Reveals Potential for Lowering Coronary Heart, Edited by Elizabeth Green, 29 May 2020,
      [5] Siri-Tarino, Patty W et al. “Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease.” The American journal of clinical nutrition vol. 91,3 (2010): 535-46. doi:10.3945/ajcn.2009.27725
      [6] Vermeer, Cees et al. “Beyond deficiency: potential benefits of increased intakes of vitamin K for bone and vascular health.” European journal of nutrition vol. 43,6 (2004): 325-35. doi:10.1007/s00394-004-0480-4
      [7] Geleijnse, Johanna M., et al. “Dietary Intake of Menaquinone Is Associated with a Reduced Risk of Coronary Heart Disease: The Rotterdam Study.OUP Academic, Oxford University Press, 1 Nov. 2004,
      [8] Bonthuis, M, et al. “Dairy Consumption and Patterns of Mortality of Australian Adults.” Nature News, Nature Publishing Group, 7 Apr. 2010, 
       [9] Eden, Rina E. “Vitamin K Deficiency.” StatPearls [Internet]., U.S. National Library of Medicine, 21 Nov. 2020,
      [10] Pharma, Natto. “NEW STUDY - VITAMIN K2 LOWERS CORONARY HEART DISEASE RISK.NattoPharma ASA, 24 June 2020,,have%20a%20higher%20cardiovascular%20risk.


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