Table of ContentsView AllTable of ContentsBlood ClottingBone HealthHeart HealthSourcesSafetyDrug Interactions
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Table of Contents
Blood Clotting
Bone Health
Heart Health
Sources
Safety
Drug Interactions
Vitamin K2 (menaquinones), a form of vitamin K, is found in some animal-based foods or fermented foods. It is mainly made from the bacteria in the gut. You can also get vitamin K2 through supplementation.
Vitamin K is a fat-soluble vitamin that is essential for certain functions in the body, such as blood clotting and bone formation. There are two main forms: vitamin K1 (phylloquinone) and vitamin K2 (menaquinones). Vitamin K2 is further broken down into different subtypes, such as MK-4 and MK-7.
In the United States, the Food and Drug Administration (FDA) does not regulate supplements the way it does for prescription drugs. This means some supplement products may not contain what the label says. Whenchoosing a supplement, look for independently tested products and consult a healthcare provider, registered dietitian nutritionist (RDN or RD), or pharmacist.
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Vitamin K2 Supports Blood Clotting
Vitamin Kis needed to make certain proteins, which are called clotting factors. Without vitamin K, the liver could not produce these clotting factors, resulting in bleeding.
Newborns are given vitamin K after birth since the transport of vitamin K through the placenta is poor. Vitamin K deficiency bleeding can occur if vitamin K is not given. The American Academy of Pediatrics recommends a 0.5–1 milligram (mg) dose given intramuscularly (into the muscle) just once to prevent bleeding.
Vitamin K2 May Protect Bone Health
Vitamin K is needed to form several proteins, includingosteocalcin, one of the main proteins found in bone.
Research on vitamin K and bone health has focused on the prevention and possible treatment of osteoporosis.Osteoporosisis a disorder that leads to weaker bones due to a loss of bone mass and bone mineral density and an increased risk offractures.
A meta-analysis of 16 studies in 6,245postmenopausalwomen suggested that vitamin K2 supplementation positively affected bone mineralization and strength.
Another recent meta-analysis reviewed studies that included supplementation with vitamin K for at least six months. The analysis concluded that vitamin K can reduce general fracture risk, but further studies are needed to establish the value of vitamin K in osteoporosis treatment.
However, some randomized clinical studies have not found vitamin K to affect bone mineral density.Although vitamin K has a role in bone health, it remains unclear if supplemental vitamin K should be used to prevent or treat osteoporosis.
Should I Take Vitamin K2 and Vitamin D3 Together?Some have suggested that taking vitamin K and D together could enhance the effects of increasing bone mass. However, there isn’t enough research to support the routine use ofvitamin D3and vitamin K2 combined.Additionally, there is some concern that this could lead to long-term soft tissue calcification and heart disease due to excess vitamin D.
Should I Take Vitamin K2 and Vitamin D3 Together?
Some have suggested that taking vitamin K and D together could enhance the effects of increasing bone mass. However, there isn’t enough research to support the routine use ofvitamin D3and vitamin K2 combined.Additionally, there is some concern that this could lead to long-term soft tissue calcification and heart disease due to excess vitamin D.
Some have suggested that taking vitamin K and D together could enhance the effects of increasing bone mass. However, there isn’t enough research to support the routine use ofvitamin D3and vitamin K2 combined.
Additionally, there is some concern that this could lead to long-term soft tissue calcification and heart disease due to excess vitamin D.
Vitamin K2 May Improve Heart Health
The role that vitamin K plays in heart health remains unclear. A protein called Matrix Gla-protein (MGP) works to prevent artery calcification, and this protein is dependent on vitamin K to do its job.
In theory, inadequate vitamin K could cause MGP to be less productive, leading to greater arterycalcification(calcium deposits). However, research has been mixed on the effectiveness of vitamin K for heart disease prevention.
One meta-analysis of 21 studies involving over 200,000 people showed that vitamin K was associated with a moderately lower risk ofcoronary heart diseasebut not mortality.Another review showed that high vitamin K2 intake was associated with reduced coronary artery calcification and heart disease risk.
However, in other studies, supplementing vitamin K has not consistently been shown to reduce calcification oratherosclerosis(plaque buildup) in the arteries.
Additionally, a meta-analysis from 2024 found that vitamin K supplementation did not affect cardiovascular risk measures like weight,C-reactive protein(CRP), lipid profiles, or glucose (sugar) metabolism.
The benefits of vitamin K2 supplementation for heart health are unclear. More research is needed to determine whether there is a place for vitamin K2 to help prevent heart disease.
Vitamin K1 vs. Vitamin K2
Vitamin K1 and vitamin K2 are both forms of vitamin K, an essential nutrient. Vitamin K2 differs from vitamin K1 in how it is absorbed and its main sources.
Vitamin K2 is also considered to have a higher absorption rate and lasts longer in the blood than vitamin K1, remaining in the blood for several days. This is believed to be because vitamin K2 is primarily found in animal-based foods, which contain fat that may lead to higher absorption.
Vitamin K1, on the other hand, is mainly found in leafy green vegetables and fruits.
How to Get Enough
The Food and Nutrition Board of the Institute of Medicine has set adequate intakes (AIs) for vitamin K. For adults, the AI for vitamin K is 90 micrograms (mcg) for women and 120 mcg for men.
Food Sources
The following are sources of vitamin K2 measured in micrograms (mcg) per 100 grams (g) of the food.
Animal-based foods containing vitamin K2 include:
It is also found in fermented foods, such as:
Supplements
Vitamin K is available as a standalone nutrient or, more commonly, in multivitamin preparations. It may also be included in a fat-soluble vitamin solution (which includes vitamins A, D, E, and K) or in preparations marketed for bone health (which includescalcium, magnesium, andvitamin D).
Vitamin K supplements come in vitamin K1 (phylloquinone or phytonadione) or vitamin K2 (MK-4 or MK-7).
People with malabsorption disorders may need vitamin K supplementation if they cannot absorb sufficient amounts of vitamin K. This may include people with celiac disease, cystic fibrosis, short bowel syndrome, or ulcerative colitis.
For disease prevention, it is best to get these nutrients from the diet. Supplementing may be helpful for those at risk of bone fractures if they have low levels of vitamins or are unable to get enough through their diet, but it should always be discussed with a healthcare provider.
Is Vitamin K2 Safe to Take?
Always speak with a healthcare provider before taking a supplement to ensure that the supplement and dosage are appropriate for your needs.
Vitamin K2 is generally considered safe for most healthy people. The amounts found in multivitamin preparations are typically less than 100% of the daily value (DV), but doses can vary in other supplement blends.
No upper limits have been established for vitamin K. According to the Food and Nutrition Board, a U.S. agency that studies issues of food safety and adequacy, no negative effects from vitamin K intake from food or supplements have been reported.
For people prescribed anticoagulant (blood-thinning) medications, such as warfarin, vitamin K intake should be discussed with their primary care provider. It is important to keep your vitamin K intake consistent each day on these medications, as adding a supplement could make them less effective.
Review your supplement label with your healthcare provider to discuss potential interactions with foods, other supplements, and medications.
Vitamin K can interact with a few medications:
Summary
Vitamin K2 is available in animal-based foods and fermented foods. Both vitamin K1 and K2 contribute to your overall vitamin K status, and deficiency is rare.
Vitamin K plays a role in blood clotting and bone health. There is some evidence that vitamin K2 supplementation may improve bone mineral density and prevent fractures. However, the evidence has not been enough for the FDA to issue a health claim for vitamin K and bone health.
Before starting any supplement, discuss with your primary care provider whether supplementation would be of benefit to you.
15 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Institute of Health Office of Dietary Supplements.Vitamin K.Holbrook A, Schulman S, Witt DM, et al.Evidence-based management of anticoagulant therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines.Chest. 2012;141(2 Suppl):e152S-e184S. doi:10.1378/chest.11-2295Ma ML, Ma ZJ, He YL, et al.Efficacy of vitamin K2 in the prevention and treatment of postmenopausal osteoporosis: A systematic review and meta-analysis of randomized controlled trials.Front Public Health. 2022;10:979649. doi:10.3389/fpubh.2022.979649Salma, Ahmad SS, Karim S, et al.Effect of vitamin K on bone mineral density and fracture risk in adults: systematic review and meta-analysis.Biomedicines. 2022;10(5):1048. doi:10.3390/biomedicines10051048Binkley N, Harke J, Krueger D, et al.Vitamin K treatment reduces undercarboxylated osteocalcin but does not alter bone turnover, density, or geometry in healthy postmenopausal North American women.J Bone Miner Res. 2009;24(6):983-991. doi:10.1359/jbmr.081254Fusaro M, Cianciolo G, Brandi ML, et al.Vitamin K and osteoporosis.Nutrients. 2020;12(12):3625. doi:10.3390/nu12123625van Ballegooijen AJ, Pilz S, Tomaschitz A, Grübler MR, Verheyen N.The synergistic interplay between vitamins D and K for bone and cardiovascular health: a narrative review.Int J Endocrinol. 2017;2017:7454376. doi:10.1155/2017/7454376Ma ML, Ma ZJ, He YL, Sun H, et al.Efficacy of vitamin K2 in the prevention and treatment of postmenopausal osteoporosis: A systematic review and meta-analysis of randomized controlled trials.Front Public Health. 2022;10:979649. doi: 10.3389/fpubh.2022.979649Hariri E, Kassis N, Iskandar JP, et al.Vitamin K2-a neglected player in cardiovascular health: a narrative review.Open Heart. 2021 Nov;8(2):e001715. doi:10.1136/openhrt-2021-001715Vlasschaert C, Goss CJ, Pilkey NG, et al.Vitamin K supplementation for the prevention of cardiovascular disease: where Is the evidence? a systematic review of controlled trials.Nutrients. 2020;12(10):2909. doi:10.3390/nu12102909Zhao QY, Li Q, Hasan et al.The effect of vitamin K supplementation on cardiovascular risk factors: a systematic review and meta-analysis.J Nutr Sci. 2024;13:e3. doi:10.1017/jns.2023.106Akbulut AC, Pavlic A, Petsophonsakul P, et al.Vitamin K2 needs an RDI separate from vitamin K1.Nutrients. 2020;12(6):1852. doi: 10.3390/nu12061852Beulens JW, Booth SL, van den Heuvel EG, et al.The role of menaquinones (vitamin K₂) in human health.Br J Nutr. 2013;110(8):1357-1368. doi:10.1017/S0007114513001013Halder M, Petsophonsakul P, Akbulut AC, et al.Vitamin K: double bonds beyond coagulation insights into differences between vitamin K1 and K2 in health and disease.Int J Mol Sci. 2019;20(4):896. doi:10.3390/ijms20040896Zhang T, O’Connor C, Sheridan H, Barlow JW.Vitamin K2 in health and disease: a clinical perspective.Foods. 2024;13(11):1646. doi: 10.3390/foods13111646
15 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Institute of Health Office of Dietary Supplements.Vitamin K.Holbrook A, Schulman S, Witt DM, et al.Evidence-based management of anticoagulant therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines.Chest. 2012;141(2 Suppl):e152S-e184S. doi:10.1378/chest.11-2295Ma ML, Ma ZJ, He YL, et al.Efficacy of vitamin K2 in the prevention and treatment of postmenopausal osteoporosis: A systematic review and meta-analysis of randomized controlled trials.Front Public Health. 2022;10:979649. doi:10.3389/fpubh.2022.979649Salma, Ahmad SS, Karim S, et al.Effect of vitamin K on bone mineral density and fracture risk in adults: systematic review and meta-analysis.Biomedicines. 2022;10(5):1048. doi:10.3390/biomedicines10051048Binkley N, Harke J, Krueger D, et al.Vitamin K treatment reduces undercarboxylated osteocalcin but does not alter bone turnover, density, or geometry in healthy postmenopausal North American women.J Bone Miner Res. 2009;24(6):983-991. doi:10.1359/jbmr.081254Fusaro M, Cianciolo G, Brandi ML, et al.Vitamin K and osteoporosis.Nutrients. 2020;12(12):3625. doi:10.3390/nu12123625van Ballegooijen AJ, Pilz S, Tomaschitz A, Grübler MR, Verheyen N.The synergistic interplay between vitamins D and K for bone and cardiovascular health: a narrative review.Int J Endocrinol. 2017;2017:7454376. doi:10.1155/2017/7454376Ma ML, Ma ZJ, He YL, Sun H, et al.Efficacy of vitamin K2 in the prevention and treatment of postmenopausal osteoporosis: A systematic review and meta-analysis of randomized controlled trials.Front Public Health. 2022;10:979649. doi: 10.3389/fpubh.2022.979649Hariri E, Kassis N, Iskandar JP, et al.Vitamin K2-a neglected player in cardiovascular health: a narrative review.Open Heart. 2021 Nov;8(2):e001715. doi:10.1136/openhrt-2021-001715Vlasschaert C, Goss CJ, Pilkey NG, et al.Vitamin K supplementation for the prevention of cardiovascular disease: where Is the evidence? a systematic review of controlled trials.Nutrients. 2020;12(10):2909. doi:10.3390/nu12102909Zhao QY, Li Q, Hasan et al.The effect of vitamin K supplementation on cardiovascular risk factors: a systematic review and meta-analysis.J Nutr Sci. 2024;13:e3. doi:10.1017/jns.2023.106Akbulut AC, Pavlic A, Petsophonsakul P, et al.Vitamin K2 needs an RDI separate from vitamin K1.Nutrients. 2020;12(6):1852. doi: 10.3390/nu12061852Beulens JW, Booth SL, van den Heuvel EG, et al.The role of menaquinones (vitamin K₂) in human health.Br J Nutr. 2013;110(8):1357-1368. doi:10.1017/S0007114513001013Halder M, Petsophonsakul P, Akbulut AC, et al.Vitamin K: double bonds beyond coagulation insights into differences between vitamin K1 and K2 in health and disease.Int J Mol Sci. 2019;20(4):896. doi:10.3390/ijms20040896Zhang T, O’Connor C, Sheridan H, Barlow JW.Vitamin K2 in health and disease: a clinical perspective.Foods. 2024;13(11):1646. doi: 10.3390/foods13111646
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
National Institute of Health Office of Dietary Supplements.Vitamin K.Holbrook A, Schulman S, Witt DM, et al.Evidence-based management of anticoagulant therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines.Chest. 2012;141(2 Suppl):e152S-e184S. doi:10.1378/chest.11-2295Ma ML, Ma ZJ, He YL, et al.Efficacy of vitamin K2 in the prevention and treatment of postmenopausal osteoporosis: A systematic review and meta-analysis of randomized controlled trials.Front Public Health. 2022;10:979649. doi:10.3389/fpubh.2022.979649Salma, Ahmad SS, Karim S, et al.Effect of vitamin K on bone mineral density and fracture risk in adults: systematic review and meta-analysis.Biomedicines. 2022;10(5):1048. doi:10.3390/biomedicines10051048Binkley N, Harke J, Krueger D, et al.Vitamin K treatment reduces undercarboxylated osteocalcin but does not alter bone turnover, density, or geometry in healthy postmenopausal North American women.J Bone Miner Res. 2009;24(6):983-991. doi:10.1359/jbmr.081254Fusaro M, Cianciolo G, Brandi ML, et al.Vitamin K and osteoporosis.Nutrients. 2020;12(12):3625. doi:10.3390/nu12123625van Ballegooijen AJ, Pilz S, Tomaschitz A, Grübler MR, Verheyen N.The synergistic interplay between vitamins D and K for bone and cardiovascular health: a narrative review.Int J Endocrinol. 2017;2017:7454376. doi:10.1155/2017/7454376Ma ML, Ma ZJ, He YL, Sun H, et al.Efficacy of vitamin K2 in the prevention and treatment of postmenopausal osteoporosis: A systematic review and meta-analysis of randomized controlled trials.Front Public Health. 2022;10:979649. doi: 10.3389/fpubh.2022.979649Hariri E, Kassis N, Iskandar JP, et al.Vitamin K2-a neglected player in cardiovascular health: a narrative review.Open Heart. 2021 Nov;8(2):e001715. doi:10.1136/openhrt-2021-001715Vlasschaert C, Goss CJ, Pilkey NG, et al.Vitamin K supplementation for the prevention of cardiovascular disease: where Is the evidence? a systematic review of controlled trials.Nutrients. 2020;12(10):2909. doi:10.3390/nu12102909Zhao QY, Li Q, Hasan et al.The effect of vitamin K supplementation on cardiovascular risk factors: a systematic review and meta-analysis.J Nutr Sci. 2024;13:e3. doi:10.1017/jns.2023.106Akbulut AC, Pavlic A, Petsophonsakul P, et al.Vitamin K2 needs an RDI separate from vitamin K1.Nutrients. 2020;12(6):1852. doi: 10.3390/nu12061852Beulens JW, Booth SL, van den Heuvel EG, et al.The role of menaquinones (vitamin K₂) in human health.Br J Nutr. 2013;110(8):1357-1368. doi:10.1017/S0007114513001013Halder M, Petsophonsakul P, Akbulut AC, et al.Vitamin K: double bonds beyond coagulation insights into differences between vitamin K1 and K2 in health and disease.Int J Mol Sci. 2019;20(4):896. doi:10.3390/ijms20040896Zhang T, O’Connor C, Sheridan H, Barlow JW.Vitamin K2 in health and disease: a clinical perspective.Foods. 2024;13(11):1646. doi: 10.3390/foods13111646
National Institute of Health Office of Dietary Supplements.Vitamin K.
Holbrook A, Schulman S, Witt DM, et al.Evidence-based management of anticoagulant therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines.Chest. 2012;141(2 Suppl):e152S-e184S. doi:10.1378/chest.11-2295
Ma ML, Ma ZJ, He YL, et al.Efficacy of vitamin K2 in the prevention and treatment of postmenopausal osteoporosis: A systematic review and meta-analysis of randomized controlled trials.Front Public Health. 2022;10:979649. doi:10.3389/fpubh.2022.979649
Salma, Ahmad SS, Karim S, et al.Effect of vitamin K on bone mineral density and fracture risk in adults: systematic review and meta-analysis.Biomedicines. 2022;10(5):1048. doi:10.3390/biomedicines10051048
Binkley N, Harke J, Krueger D, et al.Vitamin K treatment reduces undercarboxylated osteocalcin but does not alter bone turnover, density, or geometry in healthy postmenopausal North American women.J Bone Miner Res. 2009;24(6):983-991. doi:10.1359/jbmr.081254
Fusaro M, Cianciolo G, Brandi ML, et al.Vitamin K and osteoporosis.Nutrients. 2020;12(12):3625. doi:10.3390/nu12123625
van Ballegooijen AJ, Pilz S, Tomaschitz A, Grübler MR, Verheyen N.The synergistic interplay between vitamins D and K for bone and cardiovascular health: a narrative review.Int J Endocrinol. 2017;2017:7454376. doi:10.1155/2017/7454376
Ma ML, Ma ZJ, He YL, Sun H, et al.Efficacy of vitamin K2 in the prevention and treatment of postmenopausal osteoporosis: A systematic review and meta-analysis of randomized controlled trials.Front Public Health. 2022;10:979649. doi: 10.3389/fpubh.2022.979649
Hariri E, Kassis N, Iskandar JP, et al.Vitamin K2-a neglected player in cardiovascular health: a narrative review.Open Heart. 2021 Nov;8(2):e001715. doi:10.1136/openhrt-2021-001715
Vlasschaert C, Goss CJ, Pilkey NG, et al.Vitamin K supplementation for the prevention of cardiovascular disease: where Is the evidence? a systematic review of controlled trials.Nutrients. 2020;12(10):2909. doi:10.3390/nu12102909
Zhao QY, Li Q, Hasan et al.The effect of vitamin K supplementation on cardiovascular risk factors: a systematic review and meta-analysis.J Nutr Sci. 2024;13:e3. doi:10.1017/jns.2023.106
Akbulut AC, Pavlic A, Petsophonsakul P, et al.Vitamin K2 needs an RDI separate from vitamin K1.Nutrients. 2020;12(6):1852. doi: 10.3390/nu12061852
Beulens JW, Booth SL, van den Heuvel EG, et al.The role of menaquinones (vitamin K₂) in human health.Br J Nutr. 2013;110(8):1357-1368. doi:10.1017/S0007114513001013
Halder M, Petsophonsakul P, Akbulut AC, et al.Vitamin K: double bonds beyond coagulation insights into differences between vitamin K1 and K2 in health and disease.Int J Mol Sci. 2019;20(4):896. doi:10.3390/ijms20040896
Zhang T, O’Connor C, Sheridan H, Barlow JW.Vitamin K2 in health and disease: a clinical perspective.Foods. 2024;13(11):1646. doi: 10.3390/foods13111646
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