Last updated: June 15, 2020

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If you are passionate about supplementation, you probably know the main vitamins and minerals needed to stay in great health. This is why our article may surprise you; did you know that there were two types of vitamin K?

Unknown to many, vitamin K2 is a nutrient found in fermented and animal foods. This molecule combines the renowned pro-coagulant actions of vitamin K with several positive effects on both bone and cardiovascular health. Read on if you’re curious to learn more!

Key Facts

  • Vitamin K has two variants, known as vitamin K1 and K2.
  • Vitamin K2 may prevent calcium deposits in the arteries and promote bone mineralization, maintaining cardiovascular health and bone strength.
  • There are various factors to evaluate before purchasing a vitamin K2 supplement. These include your dietary needs, the molecular variant of the vitamin, and the expiration date of the supplement, among others.

Our Selection: The Best Vitamin K2 Supplements on the U.S. Market

Are you ready to reap all the benefits of vitamin K2 supplements? You have come to the right place. In the section below, we have selected some of the best products currently available out there. Praised for their efficacy and value for money, they are safe to use and will allow you to make the most of vitamin K2. All you have to do is choose the supplement that best suits your needs!

Best MK-4 Supplement

With hundreds of high ratings from past users, this vitamin K2 supplement has become Amazon’s Choice in the category. Vegan-friendly, non-GMO, and gluten-free, it contains menaquinone-4 (MK-4). Ideal to promote bone matrix and calcium metabolism, this product is also the most affordable of our selection. The recommended daily dose is one tablet. $0.09 per capsule.

Best MK-7 Supplement

Designed to support a healthy and active lifestyle, this supplement by Sports Research consists of the MK-7 molecule and coconut oil to enhance absorption by the body. Sourced from chickpea, it is completely vegan-friendly. You are advised to take one softgel per day. $0.25 per capsule.

Best Vitamin K Complex Supplement

This product is a little different from the two above, as it combines both MK-4 and MK-7 molecules with vitamin K1. This blend is perfect if you’re looking to make the most of the bone-strengthening properties of K2 with the blood coagulation capacities of K1. Note that this product is not vegan-friendly. $0.42 per capsule.

Best Liquid Vitamin K2 Supplement

Do you have difficulties swallowing tablets? If that’s the case, look no further. Mary Ruth’s Organic vitamin K2 supplement is what you need. This unflavored liquid comes in a 1-ounce bottle, and you can easily add it to your food or drink. Containing the MK-7 molecule, it is highly absorbable and vegan-friendly.

Shopping Guide: Everything You Should Know About Vitamin K2

Vitamin K2 is a little-known fat-soluble vitamin that was considered inseparable from its counterpart – vitamin K1 – for decades. This variant, however, stands out for its potential influence on the body’s calcium deposit. In that regard, it helps deposit this mineral is in the bone rather than the arteries, preventing the deterioration of the cardiovascular system.

Alimentos cocinados

No dose limit has been set for vitamin K2, although excessive consumption is not recommended.
(Source: Photodee: 80447587/ 123rf.com)

What is vitamin K2 exactly?

This fat-soluble substance is indispensable for your body’s overall balance. Also known as menaquinone, this molecule plays an essential role in the regulation of the blood clotting process and the maintenance of bone health (1).

In addition, menaquinone acts as a molecule capable of signaling and transmitting messages between different cells in the body. This is why experts believe that vitamin K2 can also be considered a hormone with stabilizing and antioxidant functions (2, 3). Here is a list of more virtues attributed to this menaquinone (4):

  • Activation of coagulation: Vitamin K2 promotes the blood clotting process, although with less intensity than other variants of this vitamin (vitamin K1).
  • Bone formation: Menaquinone contributes to the activation of the proteins required to form the bone matrix, an essential component of healthy bone (5).
  • Neuronal health: We know today that there are high levels of this vitamin in healthy brain tissue. Certain diseases, such as Parkinson’s or multiple sclerosis, show low levels of menaquinone. Thus, there have been several hypotheses regarding the role of vitamin K2 in neuronal health.
  • Cellular antioxidant: This molecule may have antioxidant functions similar to those of vitamin E. These include slowing down premature aging, both internally (kidney, liver, and heart damage) and externally (appearance of wrinkles and blemishes).
  • Control of the immune response: Vitamin K2 could regulate the production of immune system cells or white blood cells, preventing their excessive activation in healthy individuals. As you may know, a hyperfunction of the immune system can lead to various intolerances or autoimmune diseases.
  • Regulation of metabolism: Various hypotheses link vitamin K2 to the production of insulin by the pancreas and the regulation of cholesterol synthesis. This would have a positive impact on the body, helping to keep hyperglycemia and excessive cholesterol levels at bay.
  • Bone mineralization: Older adults who consume a sufficient dose of vitamin K2 have had better bone quality and strength compared to menaquinone-deficient individuals.
  • Maintenance of cardiovascular health: Vitamin K2 may hamper certain processes of arterial degeneration related to the development of atherosclerosis and worsening cardiovascular health.
  • Strengthening of dental enamel: The effect of menaquinone on oral health is talked about, with some experts believing that this vitamin may treat or improve the symptoms of gum disease and contribute to enamel maintenance.
  • Regulation of hormone production: Vitamin K2 may regulate testosterone levels in both men and women, helping to increase them in the former and lower them to normal levels in the latter.

Unfortunately, modern diets in the United States are deficient in vitamin K2. While the gut bacteria that reside symbiotically in your body can synthesize a small amount of menaquinone, any imbalance in the microbiota will expose you to a deficiency, with the potential consequences below (4, 6):

  • Hematomas and wounds caused by small blows;
  • Hard-to-stop bleeding;
  • Very abundant menstrual bleeding in women;
  • Accelerated arterial calcification, increasing the chances of suffering cardiovascular events;
  • Higher incidence of injuries and fractures.

Vitamin K2 deficiency could also have severe consequences for the metabolism, neuronal health, and aging (4). However, keep in mind that studies on menaquinone are fairly recent and may be subject to change or correction in the coming years.

cheese in cubes

Unknown to many, vitamin K2 is a nutrient found in fermented and animal foods.
(Source: Prachenko: 70364661/ 123rf.com)

What is the difference between vitamin K2 and vitamin K1?

In the world of nutrition, you will often see vitamin K referred to in a general and simplified manner. In reality, you can find up to five different forms of this vitamin, only two of which are actually useful for the human body. These vitamins are phylloquinone (K1) and menaquinone (K2) (4, 7).

  • Vitamin K1 is found in foods of plant origin, especially in the green leaves of plants such as spinach or kale. It is mainly stored in the liver and is essential for the control of blood coagulation.
  • Vitamin K2 is the result of bacterial fermentation processes. This is why it is abundant in foods of animal origin (meat, eggs, and dairy products), and in fermented foods such as cheese or natto (a Japanese dish based on fermented soybeans).

In addition to that, we can also divide vitamin K2 into smaller subclasses. K2 MK-4 is mostly found in meat products, while K2 MK-7 is much more abundant in fermented dishes. The latter is the most active form of menaquinone (5), but the least common in Western-style diets.

Therefore, the term vitamin K refers to a group of vitamins that includes menaquinone and phylloquinone. In recent years, experts have started to differentiate between the two molecules, emphasizing the unique functions of both. We have compared them in the table below (8):

Vitamin K1 Vitamin K2
Better known as vitamin K Up to 13 different MK subtypes
Commonly found in foods of plant origin Very present in animal-based and fermented foods
Essential for the blood clotting process High levels of K2 MK-4 in the brain
Stored in the liver Vitamin K2 MK-7 is distributed throughout the body.
Involved in bone formation Involved in blood coagulation
Present in proteins of cartilage tissue, tooth enamel, and male secretions Key role in bone mineralization, stimulation of new bone synthesis, and increase in bone strength
Co-factor in the creation of new proteins Prevention of arterial calcification
It may preserve neuronal function. Antioxidant effect

While vitamin K1 mainly affects coagulation, vitamin K2 shows additional benefits, such as the prevention of arterial calcification and strengthening of bones. Menaquinone can be considered a tissue booster for postmenopausal women and older adults.

What is the RDA of vitamin K2?

Unfortunately, it is virtually impossible to define a recommended daily allowance (RDA) for this molecule. Nutrition and dietary guidelines still combine menaquinone and phylloquinone into a single group (vitamin K) and recommend a common RDA for both vitamins. This RDA is measured in micrograms (μg) and varies by age and sex (9):

Population group RDA (μg)
Babies, 0-6 months 2 μg
Babies, 6-12 months 2.5 μg
Children, 1-3 years 30 μg
 Children, 4-8 years 55 μg
Adolescents, 9-13 years 60 μg
Adolescents, 14-18 years 75 μg
Adult women 90 μg
 Pregnant women 90 μg
Breastfeeding women 90 μg
Adult men 120 μg

Unofficial guidelines recommend that menaquinone should make up most of the recommended daily dose of vitamin K (around 100 micrograms of an adult male’s diet) (10). You can reach this target by eating foods rich in vitamin K2, but you may need to take supplements if you want to monitor this ratio more closely.

How can I increase my vitamin K2 levels?

The high incidence of vitamin K2 deficiency is incredibly common in our society, affecting up to 97% of individuals in specific population groups (11). To better understand and address this issue, it is essential to know several critical factors regarding menaquinone.

First of all, the low levels of vitamin K2 in Western diets play a major role. While this nutrient is present in meat, eggs, and dairy products, the primary sources of menaquinone are fermented products. In the following table, you can find out more about the concentration in different foods (12):

Food Amount of MK-4 or MK-7 (μg)
Nattō (100 g) 1,000
Chicken breast (100 g) 15
Beef (100 g) 7
Chicken liver (100 g) 7
Pork (100 g) 5
Cheddar (100 g) 5
Chicken egg 4
Mozzarella cheese 5
Whole milk (100 ml) 1
Salmon (100 g) 0.35
Prawns (100 g) 0.35

This table may have led you to an alarming conclusion: just about everyone should suffer from a lack of vitamin K2 – except for Japanese food lovers! Luckily for us, our intestinal microbiota synthesizes a small amount of menaquinone every day, thus preventing a problematic deficit (13).

That being said, any attack on this delicate bacterial balance can lead to hypovitaminosis. This is why you should take great care of your microbiota’s health. Your sensitive gut bacteria will suffer as a result of (14):

  • Excessive alcohol consumption
  • Excessive consumption of sweeteners
  • Fat- and carbohydrate-rich diet
  • Recent consumption of antibiotic treatments
  • Stress
  • Sedentarism
fish flesh

Vitamin K2 may increase your physical endurance.
(Source: Raths: 32102143/ 123rf.com)

What are the benefits of K2 supplements?

Many factors can destabilize your menaquinone levels, such as a busy lifestyle, a poor or very restrictive diet, or convalescence states. These phenomena are either direct (by reducing the intake of this vitamin) or indirect (by negatively affecting your microbiota).

If you cannot drastically modify your habits or if you want to boost your health during a physically or mentally demanding period, vitamin K2 supplements are an excellent option. The scientific studies that have been published until now indicate that menaquinone products could benefit the following groups:

  • Individuals with osteoporosis: The potential of vitamin K2 in the prevention and treatment of osteoporosis – a disease that predisposes to bone fractures – is currently being investigated. Menaquinone may facilitate calcium transport to the bones, strengthening them in people with deficient mineralization levels (5, 15, 16, 17).
  • Individuals with cardiovascular risk factors: Vitamin K2 may oppose arterial stiffness by preventing calcium deposition in the arteries. Research indicates that menaquinone appears to have a beneficial effect on cardiovascular health, significantly reducing the occurrence of heart disease (15, 18, 19, 20, 21).
  • Individuals looking to improve their physical performance: An interesting American study found that vitamin K2’s usefulness went beyond elderly people; it also seemed to increase the resistance to physical exercise in young and healthy individuals (22). There is no doubt that this promising discovery will be investigated further in the coming years.

Despite the considerable research work carried out regarding the combination of vitamin D3 and vitamin K2, the latter has been underrated for years. Its potential as a nutritional supplement on its own will require further research to confirm or disprove current hypotheses.

Buyer’s Guide

Have you made your decision to supplement with vitamin K2? If that’s the case, pay close attention to the following section. We have delved into the main shopping criteria to help you purchase the most suitable product for your needs. If you take them into account, we guarantee you will be on the right path to finding an efficient and affordable vitamin K2 supplement.

Vegan & Vegetarian Diet

D3 and K2 complex supplements are very difficult to adapt to the vegan diet, but menaquinone-based supplements tend to be vegan-friendly. Either way, don’t forget to look for a vegan seal of approval on the label and pay attention to the components of the capsules. They should consist of cellulose rather than animal gelatin.

girl eating food

Vitamin K2 may improve cardiovascular health.
(Source: Shebeko: 121749164/ 123rf.com)

Allergies & Intolerances

There have been very few reports of adverse reactions in relation to vitamin K2 supplements. Most of these intolerances are related to the content of excipients, which may include gluten and lactose. This is why you should always check the product’s ingredient list if you are an allergy-prone individual.

Menaquinone Type

The supplements currently available on the American market will contain either of the two molecular variants of vitamin K2 (MK-4 and MK-7), or a combination of both. Although MK-4 is considered to be the more active form, MK-7 seems to have a more significant effect on bone tissue. This naturally raises questions about the most efficient variant for supplementation.

Thus far, there has been no consensus on which isoform of vitamin K2 is best suited for use in supplements. Some nutritional experts recommend opting for products with both MK-4 and MK-7, combining the potency of the former with the mineralizing properties of the latter.

paella

Vitamin K2 can contribute to the deposition of calcium in the bones.
(Source: Subbotina: 119604633/ 123rf.com)

Summary

There is little doubt that vitamin K2 is a resource with incredible and untapped potential. Its existence was denied for many years or only accepted in conjunction with other similar vitamins. Today, menaquinone has proven to be a tremendously useful substance on its own.

Vitamin K2 supplements can be a turning point for people seeking to boost their bone and artery health. In addition, a menaquinone-based product may increase the stamina of active individuals, not to mention its antioxidant power!

We hope that you enjoyed our guide on vitamin K2. If so, feel free to share it on your social media and leave us a comment below.

(Source of featured image: Kps1234: 83963421/ 123rf.com)

References (24)

1. Afanasjeva J. Administration of injectable Vitamin K orally. Hosp Pharm. 2017 Oct 1;52(9):645–9.
Source

2. Vitamin K2 Oral Interactions with Other Medication [Internet]. [cited 2019 Oct 1].
Source

3. McFarlin BK, Henning AL, Venable AS. Oral consumption of vitamin K2 for 8 weeks associated with increased maximal cardiac output during exercise. Altern Ther Health Med [Internet]. 2017;23(4):26–32.
Source

4. Gast GCM, de Roos NM, Sluijs I, Bots ML, Beulens JWJ, Geleijnse JM, et al. A high menaquinone intake reduces the incidence of coronary heart disease. Nutr Metab Cardiovasc Dis. 2009 Sep;19(7):504–10.
Source

5. Gröber U, Reichrath J, Holick MF, Kisters K. Vitamin K: An old vitamin in a new perspective. Dermatoendocrinol. 2014;6(1).
Source

6. Wallin R, Schurgers L, Wajih N. Effects of the blood coagulation vitamin K as an inhibitor of arterial calcification. Thromb Res. 2008;122(3):411–7.
Source

7. Theuwissen E, Smit E, Vermeer C. The role of vitamin K in soft-tissue calcification. Adv Nutr [Internet]. 2012 Mar 1 [cited 2019 Oct 1];3(2):166–73.
Source

8. Myneni VD, Mezey E. Immunomodulatory effect of vitamin K2: Implications for bone health. Oral Dis. 2018 Mar 1;24(1–2):67–71.
Source

9. Huang Z-B, Wan S-L, Lu Y-J, Ning L, Liu C, Fan S-W. Does vitamin K2 play a role in the prevention and treatment of osteoporosis for postmenopausal women: a meta-analysis of randomized controlled trials. Osteoporos Int [Internet]. 2015 Mar [cited 2019 Oct 1];26(3):1175–86.
Source

10. Maresz K. Vitamin K 2 and Bone and Cardiovascular Health. Integr Med. 2015;14(1).
Source

11. Martin CR, Osadchiy V, Kalani A, Mayer EA. The Brain-Gut-Microbiome Axis. Vol. 6, CMGH. Elsevier Inc; 2018. p. 133–48.
Source

12. Conly JM, Stein K, Worobetz L, Rutledge-Harding S. The contribution of vitamin K2 (menaquinones) produced by the intestinal microflora to human nutritional requirements for vitamin K. Am J Gastroenterol [Internet]. 1994 Jun [cited 2019 Sep 30];89(6):915–23.
Source

13. Vitamin K — Health Professional Fact Sheet [Internet]. [cited 2019 Sep 30].
Source

14. Ej B. The Prevalence of Vitamin K Deficiency/Insufficiency, and Recommendations for Increased Intake. J Hum Nutr Food Sci. 2016;4(1):1077.
Source

15. CanPrev. Vitamin K2. A complete primer. 2018;
Source

16. Gómez C, Sastre A. Tabla de recomendaciones (normativas y recomendaciones nutricionales SEOM). 2002;317–22.
Source

17. Schwalfenberg GK. Vitamins K1 and K2: The Emerging Group of Vitamins Required for Human Health. Vol. 2017, Journal of Nutrition and Metabolism. Hindawi Limited; 2017.
Source

18. Phylloquinone - an overview | ScienceDirect Topics [Internet]. [cited 2019 Sep 29].
Source

19. Vissers LET, Dalmeijer GW, Boer JMA, Verschuren WMM, van der Schouw YT, Beulens JWJ. The relationship between vitamin K and peripheral arterial disease. Atherosclerosis. 2016 Sep 1;252:15–20.
Source

20. Myneni VD, Mezey E. Regulation of bone remodeling by vitamin K2. Vol. 23, Oral Diseases. Blackwell Publishing Ltd; 2017. p. 1021–8.
Source

21. Halder M, Petsophonsakul P, Akbulut AC, Pavlic A, Bohan F, Anderson E, et al. Vitamin K: Double Bonds beyond Coagulation Insights into Differences between Vitamin K1 and K2 in Health and Disease. Vol. 20, International journal of molecular sciences. NLM (Medline); 2019.
Source

22. Oxholm Gordeladze J. Vitamin K2: A Vitamin that Works like a Hormone, Impinging on Gene Expression. In: Cell Signalling - Thermodynamics and Molecular Control. IntechOpen; 2019.
Source

23. Norman AW (Anthony W., Litwack G. Hormones. Academic Press; 1997. 558 p.
Source

24. H. Stipanuk M, A. Caudill M. Biochemical, physiological, and molecular aspects of human nutrition. 3rd editio. Elsevier; 2013. 948 p.
Source

Why you can trust me?

Ava Kirk Journalist
Ava has specialized in medical journalism and not only writes about the human body, but also knows her way around food supplements. She also studied sports science in college.
Guía de uso
Afanasjeva J. Administration of injectable Vitamin K orally. Hosp Pharm. 2017 Oct 1;52(9):645–9.
Go to source
Revista digital científica
Vitamin K2 Oral Interactions with Other Medication [Internet]. [cited 2019 Oct 1].
Go to source
Artículo científico
McFarlin BK, Henning AL, Venable AS. Oral consumption of vitamin K2 for 8 weeks associated with increased maximal cardiac output during exercise. Altern Ther Health Med [Internet]. 2017;23(4):26–32.
Go to source
Artículo científico
Gast GCM, de Roos NM, Sluijs I, Bots ML, Beulens JWJ, Geleijnse JM, et al. A high menaquinone intake reduces the incidence of coronary heart disease. Nutr Metab Cardiovasc Dis. 2009 Sep;19(7):504–10.
Go to source
Artículo científico
Gröber U, Reichrath J, Holick MF, Kisters K. Vitamin K: An old vitamin in a new perspective. Dermatoendocrinol. 2014;6(1).
Go to source
Artículo científico
Wallin R, Schurgers L, Wajih N. Effects of the blood coagulation vitamin K as an inhibitor of arterial calcification. Thromb Res. 2008;122(3):411–7.
Go to source
Artículo científico
Theuwissen E, Smit E, Vermeer C. The role of vitamin K in soft-tissue calcification. Adv Nutr [Internet]. 2012 Mar 1 [cited 2019 Oct 1];3(2):166–73.
Go to source
Artículo científico
Myneni VD, Mezey E. Immunomodulatory effect of vitamin K2: Implications for bone health. Oral Dis. 2018 Mar 1;24(1–2):67–71.
Go to source
Artículo científico
Huang Z-B, Wan S-L, Lu Y-J, Ning L, Liu C, Fan S-W. Does vitamin K2 play a role in the prevention and treatment of osteoporosis for postmenopausal women: a meta-analysis of randomized controlled trials. Osteoporos Int [Internet]. 2015 Mar [cited 2019 Oct 1];26(3):1175–86.
Go to source
Artículo científico
Maresz K. Vitamin K 2 and Bone and Cardiovascular Health. Integr Med. 2015;14(1).
Go to source
Artículo científico
Martin CR, Osadchiy V, Kalani A, Mayer EA. The Brain-Gut-Microbiome Axis. Vol. 6, CMGH. Elsevier Inc; 2018. p. 133–48.
Go to source
Artículo científico
Conly JM, Stein K, Worobetz L, Rutledge-Harding S. The contribution of vitamin K2 (menaquinones) produced by the intestinal microflora to human nutritional requirements for vitamin K. Am J Gastroenterol [Internet]. 1994 Jun [cited 2019 Sep 30];89(6):915–23.
Go to source
NIH Office of Dietary Supplements (ODS)
Vitamin K — Health Professional Fact Sheet [Internet]. [cited 2019 Sep 30].
Go to source
Artículo científico
Ej B. The Prevalence of Vitamin K Deficiency/Insufficiency, and Recommendations for Increased Intake. J Hum Nutr Food Sci. 2016;4(1):1077.
Go to source
Guía No Oficial
CanPrev. Vitamin K2. A complete primer. 2018;
Go to source
Guía clínica SEOM
Gómez C, Sastre A. Tabla de recomendaciones (normativas y recomendaciones nutricionales SEOM). 2002;317–22.
Go to source
Artículo científico
Schwalfenberg GK. Vitamins K1 and K2: The Emerging Group of Vitamins Required for Human Health. Vol. 2017, Journal of Nutrition and Metabolism. Hindawi Limited; 2017.
Go to source
Compendio de información digital
Phylloquinone - an overview | ScienceDirect Topics [Internet]. [cited 2019 Sep 29].
Go to source
Artículo científico
Vissers LET, Dalmeijer GW, Boer JMA, Verschuren WMM, van der Schouw YT, Beulens JWJ. The relationship between vitamin K and peripheral arterial disease. Atherosclerosis. 2016 Sep 1;252:15–20.
Go to source
Artículo científico
Myneni VD, Mezey E. Regulation of bone remodeling by vitamin K2. Vol. 23, Oral Diseases. Blackwell Publishing Ltd; 2017. p. 1021–8.
Go to source
Artículo científico
Halder M, Petsophonsakul P, Akbulut AC, Pavlic A, Bohan F, Anderson E, et al. Vitamin K: Double Bonds beyond Coagulation Insights into Differences between Vitamin K1 and K2 in Health and Disease. Vol. 20, International journal of molecular sciences. NLM (Medline); 2019.
Go to source
Artículo científico
Oxholm Gordeladze J. Vitamin K2: A Vitamin that Works like a Hormone, Impinging on Gene Expression. In: Cell Signalling - Thermodynamics and Molecular Control. IntechOpen; 2019.
Go to source
Libro científico
Norman AW (Anthony W., Litwack G. Hormones. Academic Press; 1997. 558 p.
Go to source
Libro científico
H. Stipanuk M, A. Caudill M. Biochemical, physiological, and molecular aspects of human nutrition. 3rd editio. Elsevier; 2013. 948 p.
Go to source