Vitamin K

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Vitamin K consists of a group of fat-soluble vitamins essential for multiple bodily functions. The primary forms include Vitamin K1, found in plant sources, and Vitamin K2, typically found in animal products and fermented foods. Both forms are important for systemic health, with Vitamin K2 receiving focus for its broader roles. This nutrient is widely recognized for its contribution to blood coagulation. It acts as a coenzyme to activate specific clotting factors in the liver. Adequate levels are necessary to maintain the body's natural ability to manage bleeding effectively. Beyond its role in clotting, Vitamin K supports skeletal health by activating proteins that help bind calcium to the bone matrix. It also assists in managing calcium levels in soft tissues such as arteries, which contributes to overall cardiovascular integrity.

Natural sources
Leafy green vegetables (kale, spinach, collard greens, Swiss chard)BroccoliBrussels sproutsCabbageNatto (fermented soybeans - particularly rich in K2)Meat (liver, chicken)EggsHard cheesesFermented foods

Ingredient forms

No public comparison lists found.

Timing & Intake
AnytimeWith foodTake with Fat-containing meal
Because Vitamin K is fat-soluble, taking it with a meal containing some fat may help optimize absorption.
Daily Intake
RDA (Men)120 mcg
RDA (Women)90 mcg
RDI120 mcg
Optimal Dosage
Minimum100 mcg
Maximum200 mcg
Safety & Toxicity
Toxicity Effectno known toxicity
3 safety notes
  • Individuals taking anticoagulant medications (blood thinners) such as warfarin should consult a healthcare professional before taking Vitamin K supplements, as it can interfere with their medication's effectiveness.
  • Individuals with liver or kidney disease should consult a healthcare professional before supplementation.
  • Avoid excessive intake, especially if you have a medical condition affecting blood clotting.
Goals
Anti-Aging
Anti-Aging
Impact
Highest effect
Typical dose:100–500 mcg

Vitamin K2, in particular, activates proteins like osteocalcin and Matrix Gla Protein (MGP). Osteocalcin helps bind calcium to the bone matrix, while MGP prevents calcium from depositing in soft tissues like arteries and blood vessels. This dual action is fundamental for maintaining both skeletal strength and cardiovascular flexibility with age.

Focuses on
Frailty preventionCognitive maintenancePhysical mobilityVascular healthSkin elasticity
Most relevant for
Older adults seeking to maintain physical independence and cognitive health through optimized nutritional status.

Potential benefits

  • Supporting Physical Resilience.Higher vitamin K status is associated with a lower risk of developing frailty and mobility limitations in older populations, potentially helping to maintain muscle strength and physical function.
  • Cognitive Health Maintenance.Observational evidence links higher dietary vitamin K intake and serum levels to better verbal episodic memory and a slower rate of cognitive decline during aging.
  • Topical Skin Rejuvenation.In small clinical trials, topical application of vitamin K2 (MK-7) has been shown to improve skin elasticity and reduce the appearance of wrinkles and sagging.

Limitations

  • Observational Evidence.Most findings regarding frailty and cognition are based on observational studies, which do not prove that vitamin K supplementation directly causes healthier aging or extends lifespan.
  • Inconsistent Cardiovascular Results.While associated with lower all-cause mortality, meta-analyses have found that vitamin K status does not consistently correlate with a reduction in specific cardiovascular events.
  • Dietary Confounding.The cognitive benefits observed in diet-based studies may be influenced by other nutrients found in green leafy vegetables, rather than vitamin K alone.
Things to consider

Vitamin K can significantly interfere with the effectiveness of blood-thinning medications like warfarin; individuals on anticoagulant therapy should consult a healthcare provider before increasing intake.

Study evidence

27 studies

Better vitamin K status is associated with some healthier aging outcomes, but the available evidence does not establish that oral supplements slow aging or extend life. Most findings are observational, and promising skin results involve a topical preparation rather than supplementation.

View goal
Bone Health
Bone Health
Impact
Highest effect
Typical dose:90–400 mcg

Specifically, Vitamin K2 (menaquinone) is critical for directing calcium into the bones and teeth and away from soft tissues like arteries. It activates osteocalcin, a protein that incorporates calcium into bone, and Matrix Gla Protein (MGP), which prevents vascular calcification.

Focuses on
Bone Mineral DensityOsteocalcin ActivationBone MicroarchitectureFracture Risk SupportBone Mineralization
Most relevant for
Postmenopausal women with osteopenia or osteoporosis.

Potential benefits

  • Bone Mineral Density Support.Meta-analyses and long-term trials suggest that Vitamin K2 supplementation may help maintain or improve bone mineral density at the lumbar spine in postmenopausal women.
  • Protein Activation.Vitamin K is a necessary cofactor for the carboxylation of osteocalcin, the protein responsible for binding calcium to the bone matrix to support mineralization.
  • Bone Geometry Maintenance.Some studies indicate that Vitamin K may help preserve the structural microarchitecture and strength of trabecular bone in the hip and tibia, even when overall density measurements do not change.

Limitations

  • Inconsistent Fracture Prevention.Clinical results are mixed regarding fracture reduction; some trials show no additional protective benefit when Vitamin K is added to standard osteoporosis medications.
  • Variable Bone Density Impact.Multiple high-quality, long-term randomized trials found that Vitamin K supplementation failed to prevent the general age-related decline in bone mineral density compared to placebo.
  • Population Constraints.Research primarily shows effects in postmenopausal women with existing low bone density; there is limited evidence of benefit for healthy premenopausal women or younger populations.
Things to consider

Vitamin K intake can interfere with the effectiveness of anticoagulant medications like warfarin. Some clinical trials have reported higher rates of non-serious adverse reactions and treatment discontinuation in Vitamin K supplementation groups.

Study evidence

78 studies

Vitamin K helps activate proteins involved in bone mineralization, and supplements may improve some bone-density measures, particularly in postmenopausal women. However, clinical results are inconsistent, and changes in these proteins do not reliably translate into stronger bones or fewer fractures.

View goal
Cardiovascular Support
Cardiovascular Support
Impact
Highest effect
Typical dose:90–200 mcg

While often known for blood clotting (Vitamin K1), the K2 form (specifically MK-7) is vital for cardiovascular health. It activates proteins that inhibit calcium deposition in arterial walls, a key factor in atherosclerosis and arterial stiffening. This helps maintain blood vessel elasticity and function.

Focuses on
Arterial CalcificationVascular StiffnessBlood Vessel ElasticityMatrix Gla Protein ActivationCoronary Health
Most relevant for
Postmenopausal women with arterial stiffness and individuals with high-risk vascular calcification, such as those on dialysis.

Potential benefits

  • Arterial Stiffness Support.Long-term Vitamin K2 (MK-7) supplementation may improve arterial elasticity and pulse wave velocity in postmenopausal women with high baseline vascular stiffness.
  • Calcification Management.In patients undergoing dialysis, Vitamin K supplementation has been shown to slow the progression of coronary and aortic calcification.
  • Vascular Protein Activation.Unconfirmed. Supplementation effectively activates Matrix Gla protein, which inhibits arterial calcification, but it is unconfirmed if this biological marker reliably leads to better cardiovascular outcomes.

Limitations

  • Null Findings in Chronic Disease.Clinical trials in individuals with type 2 diabetes or chronic kidney disease have found no significant effect on arterial calcification or stiffness.
  • Unproven Clinical Prevention.Supplements have not been shown to prevent major cardiovascular events, such as heart attacks, strokes, or overall cardiovascular mortality.
  • Observational Data Conflicts.Cohort studies on dietary Vitamin K show inconsistent associations with heart health, with some studies finding benefits only for specific forms like K1 or K2.
Things to consider

Individuals taking Vitamin K antagonists like warfarin should consult a healthcare provider, as Vitamin K is involved in blood clotting and can interfere with the effectiveness of these medications.

Study evidence

40 studies

Vitamin K is involved in processes that limit blood-vessel calcification, but supplementation has not consistently improved vascular health. Some studies report benefits in selected groups, while many find no effect; the available evidence does not establish that supplements prevent heart attacks or strokes.

View goal
General Health
General Health
Impact
Highest effect
Typical dose:100–200 mcg

Primarily in its K2 form, this vitamin is crucial for proper calcium metabolism. It activates proteins that help bind calcium to the bone matrix and prevent its accumulation in soft tissues like arteries, where it can cause calcification. It is an essential partner to Vitamin D supplementation.

Focuses on
Bone mineral densityCardiovascular supportPhysical functionLongevityRespiratory health
Most relevant for
Older adults and postmenopausal women looking to support long-term skeletal and heart health.

Potential benefits

  • Bone Health Support.Unconfirmed. Vitamin K2 may help maintain bone mineral density in the spine and reduce fracture risk in postmenopausal women, particularly when used with Vitamin D and calcium.
  • Arterial Health.Unconfirmed. High dietary intake and supplementation have been linked to reduced coronary artery calcification and a lower risk of coronary heart disease.
  • Lower Mortality Risk.Unconfirmed. Large observational studies consistently associate higher vitamin K status and dietary intake with a lower risk of all-cause and cardiovascular mortality.

Limitations

  • Inconsistent Supplement Evidence.While higher dietary intake is linked to better health, randomized trials have often failed to show that supplements improve physical function or prevent bone loss in healthy adults.
  • Form-Specific Differences.Research often shows conflicting results between K1 and K2 forms; for example, some heart benefits are associated specifically with K2, while lung health links are stronger for K1.
  • Population Constraints.Many documented benefits are observed primarily in specific groups, such as postmenopausal women or individuals with kidney transplants, rather than the general population.
Things to consider

Vitamin K can significantly interfere with the effectiveness of blood-thinning medications like warfarin; individuals on anticoagulants must maintain a consistent intake and consult a physician.

Study evidence

34 studies

Vitamin K has an established role in preventing deficiency-related bleeding, especially through newborn prophylaxis. For broader adult health, higher intake or better vitamin K status is linked with favorable outcomes, but supplements have not reliably demonstrated wide-ranging benefits.

View goal
Heart Health
Heart Health
Impact
Highest effect
Typical dose:90–300 mcg

The K2 form (specifically MK-7) activates matrix Gla-protein (MGP), the most potent inhibitor of vascular calcification. By ensuring calcium is deposited in bone rather than soft tissues, Vitamin K2 directly contributes to maintaining arterial flexibility and preventing stiffness.

Focuses on
Arterial flexibilityVascular calcificationCalcium metabolismHeart health markers
Most relevant for
Postmenopausal women and older adults seeking to support arterial elasticity and proper calcium distribution within the cardiovascular system.

Potential benefits

  • Vascular Elasticity Support.Unconfirmed. Clinical studies suggest that Vitamin K2 (MK-7) may help maintain arterial flexibility in postmenopausal women, though this benefit is currently unconfirmed for the general population due to mixed trial results in other groups.
  • Calcium Management in Arteries.Unconfirmed. Vitamin K helps activate proteins that inhibit calcium buildup in vessel walls; while research indicates it may slow progression in older adults with existing calcification, its effectiveness for general heart disease prevention is not yet proven.

Limitations

  • Mixed Results in Chronic Conditions.Clinical trials in individuals with diabetes or chronic kidney disease often show no significant improvement in arterial stiffness or calcification scores after supplementation.
  • No Proven Reduction in Major Events.Supplements have not been shown to reduce the risk of clinical events like heart attacks or cardiovascular death, despite their effect on certain vascular biomarkers.
  • Limited Evidence for Healthy Adults.Evidence for heart health benefits in healthy younger adults is sparse, with most supportive data coming from observational studies or specific populations with existing deficiencies.
Things to consider

Some research has noted that high-dose Vitamin K1 supplementation may unfavorably increase triglyceride levels in postmenopausal women.

Study evidence

62 studies

Vitamin K activates proteins involved in limiting artery calcification, and higher dietary intake is sometimes linked with better heart health. Supplement trials have produced inconsistent vascular benefits, however, and the available evidence does not establish that Vitamin K supplements prevent heart attacks or cardiovascular deaths.

View goal
Joint Health
Joint Health
Impact
Situational effect
Typical dose:90–200 mcg

Vitamin K, particularly the K2 form, activates proteins responsible for bone mineralization and inhibiting vascular and cartilage calcification. Low vitamin K status is associated with a higher prevalence of osteoarthritis.

Focuses on
Cartilage mineralizationOsteoarthritis riskJoint space maintenanceCartilage preservationNutritional adequacy
Most relevant for
Individuals concerned about age-related joint issues who may have low dietary intake of vitamin K.

Potential benefits

  • Cartilage Integrity.Unconfirmed. Observational studies link adequate vitamin K levels to reduced progression of cartilage and meniscus damage, though clinical trials have not confirmed a protective effect from supplements. This benefit for joint health is unproven.
  • Osteoarthritis Risk Management.Unconfirmed. Higher dietary intake is associated with a lower prevalence of knee and hand osteoarthritis in population studies, but genetic evidence does not support a causal link. This benefit for joint health is unproven.
  • Joint Tissue Mineralization.Unconfirmed. Vitamin K activates proteins like Matrix Gla Protein that help regulate the mineralization of cartilage, a process relevant to maintaining joint structure. This benefit for joint health is unproven.

Limitations

  • Lack of Clinical Confirmation.A randomized controlled trial found no overall effect of vitamin K supplementation on radiographic hand osteoarthritis or joint space narrowing.
  • Unproven Causal Relationship.Mendelian randomization studies suggest that genetically predicted vitamin K levels are not causally associated with a reduced risk of osteoarthritis.
  • Mixed Structural Evidence.While some data link higher intake to improved symptoms, findings regarding structural improvements in joints remain inconsistent and are often restricted to correcting a deficiency.
Things to consider

Vitamin K can interfere with the efficacy of blood-thinning medications such as warfarin; individuals on anticoagulants should consult a healthcare provider before use.

Study evidence

14 studies

Low vitamin K status is associated with osteoarthritis and worsening joint damage, but this does not prove that supplements protect joints. The available supplementation trial found no overall benefit, leaving possible advantages from correcting low status uncertain.

View goal

Studies

Research connections will load here.
Sources

Up to five highest-ranked published examples per goal. Study counts and charts include all published studies for the connection.

  1. Vitamin K status, cardiovascular disease, and all-cause mortality: a participant-level meta-analysis of 3 US cohorts.
    Shea MK; Barger K; Booth SL; Matuszek G; Cushman M; Benjamin EJ; Kritchevsky SB; Weiner DE · The American journal of clinical nutrition · 2020
    Meta-analysis3,891 participants3 studies pooledGeneral HealthAnti-Aging
  2. Topical Menaquinone‑7 (Vitamin K2, MK-7) as a Mitochondrial Bioenergetic Activator for Skin Anti-Aging: Mechanistic Evidence in Skin Cells and a Randomized Split-Face/Neck Study.
    Huang H; Wei R; Xu C; Liu C; Zhao S; Li Y; Wang M · ACS omega · 2026
    Randomized trial30 participantsAnti-Aging
  3. Vitamin K status and cognitive function in healthy older adults.
    Presse N; Belleville S; Gaudreau P; Greenwood CE; Kergoat MJ; Morais JA; Payette H; Shatenstein B; Ferland G · Neurobiology of aging · 2014
    Cross-sectional study320 participantsAnti-Aging
  4. High dephospho-uncarboxylated matrix Gla protein concentrations, a plasma biomarker of vitamin K, in relation to frailty: the Longitudinal Aging Study Amsterdam.
    Machado-Fragua MD; Hoogendijk EO; Struijk EA; Rodriguez-Artalejo F; Lopez-Garcia E; Beulens JW; van Ballegooijen AJ · European journal of nutrition · 2021
    Cohort study644 participantsAnti-Aging
  5. Vitamin K Concentration and Cognitive Status in Elderly Patients on Anticoagulant Therapy: A Pilot Study.
    Alisi L; Cafolla C; Gentili A; Tartaglione S; Curini R; Cafolla A · Journal of aging research · 2022
    Cross-sectional study85 participantsAnti-Aging
  6. Vitamin K and the prevention of fractures: systematic review and meta-analysis of randomized controlled trials.
    Cockayne S; Adamson J; Lanham-New S; Shearer MJ; Gilbody S; Torgerson DJ · Archives of internal medicine · 2006
    Meta-analysis13 studies pooledBone Health
  7. Three-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy postmenopausal women.
    Knapen MH; Drummen NE; Smit E; Vermeer C; Theuwissen E · Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA · 2014
    Randomized trial244 participantsBone Health
  8. Effect of combined administration of vitamin D3 and vitamin K2 on bone mineral density of the lumbar spine in postmenopausal women with osteoporosis.
    Iwamoto J; Takeda T; Ichimura S · Journal of orthopaedic science : official journal of the Japanese Orthopaedic Association · 2001
    Randomized trial92 participantsBone Health
  9. Efficacy and safety of vitamin K2 for postmenopausal women with osteoporosis at a long-term follow-up: meta-analysis and systematic review.
    Zhou M; Han S; Zhang W; Wu D · Journal of bone and mineral metabolism · 2022
    Meta-analysis6,853 participants9 studies pooledBone Health
  10. Low-dose vitamin K2 (MK-4) supplementation for 12 months improves bone metabolism and prevents forearm bone loss in postmenopausal Japanese women.
    Koitaya N; Sekiguchi M; Tousen Y; Nishide Y; Morita A; Yamauchi J; Gando Y; Miyachi M; Aoki M; Komatsu M; Watanabe F; Morishita K; Ishimi Y · Journal of bone and mineral metabolism · 2015
    Randomized trial48 participantsBone Health
  11. Vitamin K Intake and Atherosclerotic Cardiovascular Disease in the Danish Diet Cancer and Health Study.
    Bellinge JW; Dalgaard F; Murray K; Connolly E; Blekkenhorst LC; Bondonno CP; Lewis JR; Sim M; Croft KD; Gislason G; Torp-Pedersen C; Tjønneland A; Overvad K; Hodgson JM; Schultz C; Bondonno NP · Journal of the American Heart Association · 2021
    Cohort study53,372 participantsCardiovascular SupportHeart Health
  12. Menaquinone-7 supplementation improves arterial stiffness in healthy postmenopausal women. A double-blind randomised clinical trial.
    Knapen MH; Braam LA; Drummen NE; Bekers O; Hoeks AP; Vermeer C · Thrombosis and haemostasis · 2016
    Randomized trial244 participantsCardiovascular SupportHeart Health
  13. Effects of One-Year Menaquinone-7 Supplementation on Vascular Stiffness and Blood Pressure in Post-Menopausal Women.
    de Vries F; Bittner R; Maresz K; Machuron F; Gåserød O; Jeanne JF; Schurgers LJ · Nutrients · 2025
    Randomized trial165 participantsCardiovascular Support
  14. Dietary Vitamin K1 Intake and Incident Aortic Valve Stenosis.
    Schultz CJ; Dalgaard F; Bellinge JW; Murray K; Sim M; Connolly E; Blekkenhorst LC; Bondonno CP; Lewis JR; Gislason GH; Tjønneland A; Overvad K; Hodgson JM; Bondonno NP · Arteriosclerosis, thrombosis, and vascular biology · 2024
    Cohort study55,545 participantsCardiovascular SupportHeart Health
  15. Association between vitamin K1 intake and mortality in the Danish Diet, Cancer, and Health cohort.
    Palmer CR; Bellinge JW; Dalgaard F; Sim M; Murray K; Connolly E; Blekkenhorst LC; Bondonno CP; Croft KD; Gislason G; Tjønneland A; Overvad K; Schultz C; Lewis JR; Hodgson JM; Bondonno NP · European journal of epidemiology · 2021
    Cohort study56,048 participantsHeart HealthCardiovascular Support
  16. Dietary vitamin K intake associates with reduced all-cause mortality in non-alcoholic fatty liver disease patients.
    Huang Y; Zhu X; Han L; Hu H · Scientific reports · 2025
    Cohort study7,857 participantsGeneral Health
  17. The Effect of Topical Vitamin K1 on the Treatment of Cetuximab-Induced Skin Rashes in Metastatic Colorectal Cancer Patients.
    Roayaei M; Rezaei M; Najafizade N · Advanced biomedical research · 2024
    Randomized trial49 participantsGeneral Health
  18. Effect of vitamin K on improving post‑kidney transplant outcomes: a meta‑analysis.
    Sun Z; Zhu K; Liang G; Yan F; Chao S; Jia L; Niu Y · Experimental and therapeutic medicine · 2023
    Meta-analysis7 studies pooledGeneral Health
  19. Vitamin K1 intake is associated with lower risk for all-cause and cardiovascular disease mortality in community-dwelling older Australian women.
    Dupuy M; Radavelli-Bagatini S; Zhong L; Dalla Via J; Zhu K; Blekkenhorst LC; Bondonno NP; Linneberg A; Bellinge JW; Schultz C; Courtney W; Prince RL; Hodgson JM; Lewis JR; Sim M · Nutrition, metabolism, and cardiovascular diseases : NMCD · 2024
    Cohort study1,436 participantsGeneral Health
  20. The effect of vitamin K1 on arterial calcification activity in subjects with diabetes mellitus: a post hoc analysis of a double-blind, randomized, placebo-controlled trial.
    Bellinge JW; Francis RJ; Lee SC; Bondonno NP; Sim M; Lewis JR; Watts GF; Schultz CJ · The American journal of clinical nutrition · 2022
    Randomized trial149 participantsHeart Health
  21. Low vitamin K status is associated with osteoarthritis in the hand and knee.
    Neogi T; Booth SL; Zhang YQ; Jacques PF; Terkeltaub R; Aliabadi P; Felson DT · Arthritis and rheumatism · 2006
    Cohort study672 participantsJoint Health
  22. Associations Between Dietary Intake of Vitamin K and Changes in Symptomatic and Structural Changes in Patients With Knee Osteoarthritis.
    Liao Z; Chang J; Zhu Z; Han W; Meng T; Zheng S; Tu L; Antony B; Winzenberg T; Wluka AE; Cicuttini F; Ding C · Arthritis care & research · 2023
    Cohort study259 participantsJoint Health
  23. Association of low dietary vitamin K intake with radiographic knee osteoarthritis in the Japanese elderly population: dietary survey in a population-based cohort of the ROAD study.
    Oka H; Akune T; Muraki S; En-yo Y; Yoshida M; Saika A; Sasaki S; Nakamura K; Kawaguchi H; Yoshimura N · Journal of orthopaedic science : official journal of the Japanese Orthopaedic Association · 2010
    Cross-sectional study719 participantsJoint Health
  24. The Relationship between Vitamin K and Osteoarthritis: A Review of Current Evidence.
    Chin KY · Nutrients · 2021
    Narrative reviewJoint Health
  25. Vitamin K deficiency is associated with incident knee osteoarthritis.
    Misra D; Booth SL; Tolstykh I; Felson DT; Nevitt MC; Lewis CE; Torner J; Neogi T · The American journal of medicine · 2013
    Cohort study1,180 participantsJoint Health