Vitamin K

Last Updated: September 28, 2022

Vitamin K is an essential vitamin found in plants or produced from intestinal bacteria. It plays an essential role in bone health and regulates blood clotting.

Vitamin K is most often used for

Summary

Vitamin K is an essential vitamin. It is one of the four fat-soluble vitamins, along with vitamin A, vitamin D, and vitamin E. It was named vitamin K after the German word koagulation, because vitamin K’s role in blood coagulation was first discovered in Germany. Vitamin K can be found in dark green vegetables, matcha tea, and natto (a type of fermented soybeans). Vitamin K can also be found in various animal products.

The Recommended Daily Intake (RDI) of vitamin K is sufficient to support healthy blood coagulation. Higher levels of vitamin K, however, may provide additional benefits. Unfortunately, it can be difficult to obtain high levels of vitamin K from food alone. Most people don’t like natto enough to eat 50g a day, so supplementation of vitamin K is a popular option.

Vitamin K has at times been found to improve markers of bone health. Despite this, supplementation has inconsistent effects on bone fracture risk.

Vitamin K has been suggested to protect cardiovascular health by reducing the calcification and stiffening of arteries. However, a number of clinical trials have found no apparent effect of vitamin K supplementation on arterial calcification. Most of these trials were on people with extensive arterial calcification already present, meaning additional research is needed to determine if vitamin K can prevent tissue calcification before it has started.

Vitamin K may have a role to play in cancer therapy. It may also help with regulating insulin sensitivity and (in topical form) may help reduce skin reddening, but more research is needed before strong conclusions can be drawn.

Vitamin K’s main mechanism is through the vitamin K cycle, which is a cyclical metabolic pathway that uses vitamin K to modify various proteins. Specifically, vitamin K is used to attach a carbon dioxide molecule onto a glutamate contained in these proteins, allowing the protein to bind calcium ions. These proteins can then utilize calcium ions for various biological processes.

Vitamin K is often supplemented alongside vitamin D, since vitamin D also supports bone health. In fact, taking both together may improve the effects of each, since they are believed to work synergistically. Excessive vitamin D can lead to arterial calcification and in animal models vitamin K reduces this buildup.

What else is Vitamin K known as?
Note that Vitamin K is also known as:
  • Phylloquinone
  • Menaquinone
  • MK-4
  • MK-7
  • Menatetrenone
  • Phytonadione
Vitamin K should not be confused with:
Dosage information

Vitamin K comes in a variety of different forms, known as vitamers. Forms of vitamin K are either phylloquinones (vitamin K1) or menaquinones (vitamin K2). There are different vitamers within the vitamin K2 class, abbreviated as MK-x.

The minimum effective dose for phylloquinone (vitamin K1) is 50mcg, which is enough to satisfy the Recommended Daily Intake (RDI) for vitamin K. The maximum dose for vitamin K1 is 10,000mcg (10 mg).

The minimum effective dose for short chain menaquinones (MK-4) is 1,500mcg. Doses of up to 45mg (45,000mcg) have been safely used in a superloading dosing protocol.

The minimum effective dose for longer chain menaquinones (MK-7, MK-8, and MK-9) is between 90-360mcg. Further research is needed to determine the maximum effective dose for MK-7.

A topical application of vitamin K should contain at least 5% phylloquinone.

Vitamin K should be supplemented alongside fatty acids, even if the vitamin is coming from a plant-based source, so consider taking vitamin K at meal time. Microwaving plant-based sources of vitamin K will increase the absorption rate of the vitamin.

Examine Database: Vitamin K
What works and what doesn't?

Unlock the full potential of Examine

Get started

Don't miss out on the latest research

Frequently asked questions

Other FAQs

Research Breakdown

🚧 Under Renovation 🚧

The information in this section is slated for renovation — it will soon be transformed into a more usable (and readable!) form in the coming months. As such, the text in this section may be out of date and not up to Examine’s current standards for writing style.

References
  1. ^Dam HThe antihaemorrhagic vitamin of the chickBiochem J.(1935 Jun)
  2. ^Booth SLRoles for vitamin K beyond coagulationAnnu Rev Nutr.(2009)
  3. ^Shearer MJ, Newman PRecent trends in the metabolism and cell biology of vitamin K with special reference to vitamin K cycling and MK-4 biosynthesisJ Lipid Res.(2014 Mar)
  4. ^Garber AK, Binkley NC, Krueger DC, Suttie JWComparison of phylloquinone bioavailability from food sources or a supplement in human subjectsJ Nutr.(1999 Jun)
  5. ^Gijsbers BL, Jie KS, Vermeer CEffect of food composition on vitamin K absorption in human volunteersBr J Nutr.(1996 Aug)
  6. ^Ageno W, Gallus AS, Wittkowsky A, Crowther M, Hylek EM, Palareti GOral anticoagulant therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice GuidelinesChest.(2012 Feb)
  7. ^Booth SLVitamin K: food composition and dietary intakesFood Nutr Res.(2012)
  8. ^Kurosu M, Begari EVitamin K2 in electron transport system: are enzymes involved in vitamin K2 biosynthesis promising drug targets?Molecules.(2010 Mar 10)
  9. ^Shearer MJ, Newman PMetabolism and cell biology of vitamin KThromb Haemost.(2008 Oct)
  10. ^Davidson RT, Foley AL, Engelke JA, Suttie JWConversion of dietary phylloquinone to tissue menaquinone-4 in rats is not dependent on gut bacteriaJ Nutr.(1998 Feb)
  11. ^Ronden JE, Drittij-Reijnders MJ, Vermeer C, Thijssen HHIntestinal flora is not an intermediate in the phylloquinone-menaquinone-4 conversion in the ratBiochim Biophys Acta.(1998 Jan 8)
  12. ^Beulens JW, Booth SL, van den Heuvel EG, Stoecklin E, Baka A, Vermeer CThe role of menaquinones (vitamin K₂) in human healthBr J Nutr.(2013 Oct)
  13. ^Miggiano GA, Robilotta LVitamin K-controlled diet: problems and prospectsClin Ter.(2005 Jan-Apr)
  14. ^Ichihashi T, Takagishi Y, Uchida K, Yamada HColonic absorption of menaquinone-4 and menaquinone-9 in ratsJ Nutr.(1992 Mar)
  15. ^Holmes MV, Hunt BJ, Shearer MJThe role of dietary vitamin K in the management of oral vitamin K antagonistsBlood Rev.(2012 Jan)
  16. ^Ikeda Y, Iki M, Morita A, Kajita E, Kagamimori S, Kagawa Y, Yoneshima HIntake of fermented soybeans, natto, is associated with reduced bone loss in postmenopausal women: Japanese Population-Based Osteoporosis (JPOS) StudyJ Nutr.(2006 May)
  17. ^Katsuyama H, Ideguchi S, Fukunaga M, Saijoh K, Sunami SUsual dietary intake of fermented soybeans (Natto) is associated with bone mineral density in premenopausal womenJ Nutr Sci Vitaminol (Tokyo).(2002 Jun)
  18. ^Sato T, Schurgers LJ, Uenishi KComparison of menaquinone-4 and menaquinone-7 bioavailability in healthy womenNutr J.(2012 Nov 12)
  19. ^Vermeer CVitamin K: the effect on health beyond coagulation - an overviewFood Nutr Res.(2012)
  20. ^Schurgers LJ, Teunissen KJ, Hamulyák K, Knapen MH, Vik H, Vermeer CVitamin K-containing dietary supplements: comparison of synthetic vitamin K1 and natto-derived menaquinone-7Blood.(2007 Apr 15)
  21. ^Schurgers LJ, Vermeer CDifferential lipoprotein transport pathways of K-vitamins in healthy subjectsBiochim Biophys Acta.(2002 Feb 15)
  22. ^Schurgers LJ, Vermeer CDetermination of phylloquinone and menaquinones in food. Effect of food matrix on circulating vitamin K concentrationsHaemostasis.(2000 Nov-Dec)
  23. ^Nakagawa K, Hirota Y, Sawada N, Yuge N, Watanabe M, Uchino Y, Okuda N, Shimomura Y, Suhara Y, Okano TIdentification of UBIAD1 as a novel human menaquinone-4 biosynthetic enzymeNature.(2010 Nov 4)
  24. ^Shearer MJVitamin KLancet.(1995 Jan 28)
  25. ^American Academy of Pediatrics Committee on Fetus and NewbornControversies concerning vitamin K and the newborn. American Academy of Pediatrics Committee on Fetus and NewbornPediatrics.(2003 Jul)
  26. ^Spronk HM, Soute BA, Schurgers LJ, Thijssen HH, De Mey JG, Vermeer CTissue-specific utilization of menaquinone-4 results in the prevention of arterial calcification in warfarin-treated ratsJ Vasc Res.(2003 Nov-Dec)
  27. ^Groenen-van Dooren MM, Soute BA, Jie KS, Thijssen HH, Vermeer CThe relative effects of phylloquinone and menaquinone-4 on the blood coagulation factor synthesis in vitamin K-deficient ratsBiochem Pharmacol.(1993 Aug 3)
  28. ^Theuwissen E, Teunissen KJ, Spronk HM, Hamulyák K, Ten Cate H, Shearer MJ, Vermeer C, Schurgers LJEffect of low-dose supplements of menaquinone-7 (vitamin K2 ) on the stability of oral anticoagulant treatment: dose-response relationship in healthy volunteersJ Thromb Haemost.(2013 Jun)
  29. ^Schurgers LJ, Shearer MJ, Hamulyák K, Stöcklin E, Vermeer CEffect of vitamin K intake on the stability of oral anticoagulant treatment: dose-response relationships in healthy subjectsBlood.(2004 Nov 1)
  30. ^Ushiroyama T, Ikeda A, Ueki MEffect of continuous combined therapy with vitamin K(2) and vitamin D(3) on bone mineral density and coagulofibrinolysis function in postmenopausal womenMaturitas.(2002 Mar 25)
  31. ^Asakura H, Myou S, Ontachi Y, Mizutani T, Kato M, Saito M, Morishita E, Yamazaki M, Nakao SVitamin K administration to elderly patients with osteoporosis induces no hemostatic activation, even in those with suspected vitamin K deficiencyOsteoporos Int.(2001 Dec)
  32. ^Mayer O Jr, Seidlerová J, Bruthans J, Filipovský J, Timoracká K, Vaněk J, Cerná L, Wohlfahrt P, Cífková R, Theuwissen E, Vermeer CDesphospho-uncarboxylated matrix Gla-protein is associated with mortality risk in patients with chronic stable vascular diseaseAtherosclerosis.(2014 Jul)
  33. ^Chatrou ML, Winckers K, Hackeng TM, Reutelingsperger CP, Schurgers LJVascular calcification: the price to pay for anticoagulation therapy with vitamin K-antagonistsBlood Rev.(2012 Jul)
  34. ^Gast GC, de Roos NM, Sluijs I, Bots ML, Beulens JW, Geleijnse JM, Witteman JC, Grobbee DE, Peeters PH, van der Schouw YTA high menaquinone intake reduces the incidence of coronary heart diseaseNutr Metab Cardiovasc Dis.(2009 Sep)
  35. ^Beulens JW, Bots ML, Atsma F, Bartelink ML, Prokop M, Geleijnse JM, Witteman JC, Grobbee DE, van der Schouw YTHigh dietary menaquinone intake is associated with reduced coronary calcificationAtherosclerosis.(2009 Apr)
  36. ^Geleijnse JM, Vermeer C, Grobbee DE, Schurgers LJ, Knapen MH, van der Meer IM, Hofman A, Witteman JCDietary intake of menaquinone is associated with a reduced risk of coronary heart disease: the Rotterdam StudyJ Nutr.(2004 Nov)
  37. ^El Asmar MS, Naoum JJ, Arbid EJVitamin k dependent proteins and the role of vitamin k2 in the modulation of vascular calcification: a reviewOman Med J.(2014 May)
  38. ^Shea MK, O'Donnell CJ, Hoffmann U, Dallal GE, Dawson-Hughes B, Ordovas JM, Price PA, Williamson MK, Booth SLVitamin K supplementation and progression of coronary artery calcium in older men and womenAm J Clin Nutr.(2009 Jun)
  39. ^Braam LA, Hoeks AP, Brouns F, Hamulyák K, Gerichhausen MJ, Vermeer CBeneficial effects of vitamins D and K on the elastic properties of the vessel wall in postmenopausal women: a follow-up studyThromb Haemost.(2004 Feb)
  40. ^Kurnatowska I, Grzelak P, Masajtis-Zagajewska A, Kaczmarska M, Stefańczyk L, Vermeer C, Maresz K, Nowicki MEffect of vitamin K2 on progression of atherosclerosis and vascular calcification in nondialyzed patients with chronic kidney disease stages 3-5Pol Arch Med Wewn.(2015)
  41. ^Knapen MH, Braam LA, Drummen NE, Bekers O, Hoeks AP, Vermeer CMenaquinone-7 supplementation improves arterial stiffness in healthy postmenopausal women. A double-blind randomised clinical trialThromb Haemost.(2015 May)
  42. ^Fulton RL, McMurdo ME, Hill A, Abboud RJ, Arnold GP, Struthers AD, Khan F, Vermeer C, Knapen MH, Drummen NE, Witham MDEffect of Vitamin K on Vascular Health and Physical Function in Older People with Vascular Disease--A Randomised Controlled TrialJ Nutr Health Aging.(2016 Mar)
  43. ^Caraballo PJ, Heit JA, Atkinson EJ, Silverstein MD, O'Fallon WM, Castro MR, Melton LJ 3rdLong-term use of oral anticoagulants and the risk of fractureArch Intern Med.(1999 Aug 9-23)
  44. ^Gage BF, Birman-Deych E, Radford MJ, Nilasena DS, Binder EFRisk of osteoporotic fracture in elderly patients taking warfarin: results from the National Registry of Atrial Fibrillation 2Arch Intern Med.(2006 Jan 23)
  45. ^Jamal SA, Browner WS, Bauer DC, Cummings SRWarfarin use and risk for osteoporosis in elderly women. Study of Osteoporotic Fractures Research GroupAnn Intern Med.(1998 May 15)
  46. ^Hodges SJ, Pilkington MJ, Shearer MJ, Bitensky L, Chayen JAge-related changes in the circulating levels of congeners of vitamin K2, menaquinone-7 and menaquinone-8Clin Sci (Lond).(1990 Jan)
  47. ^Pisani P, Renna MD, Conversano F, Casciaro E, Di Paola M, Quarta E, Muratore M, Casciaro SMajor osteoporotic fragility fractures: Risk factor updates and societal impactWorld J Orthop.(2016 Mar 18)
  48. ^Dhanwal DK, Dennison EM, Harvey NC, Cooper CEpidemiology of hip fracture: Worldwide geographic variationIndian J Orthop.(2011 Jan)
  49. ^Johnell O, Kanis JAAn estimate of the worldwide prevalence and disability associated with osteoporotic fracturesOsteoporos Int.(2006 Dec)
  50. ^Fang Y, Hu C, Tao X, Wan Y, Tao FEffect of vitamin K on bone mineral density: a meta-analysis of randomized controlled trialsJ Bone Miner Metab.(2012 Jan)
  51. ^Cockayne S, Adamson J, Lanham-New S, Shearer MJ, Gilbody S, Torgerson DJVitamin K and the prevention of fractures: systematic review and meta-analysis of randomized controlled trialsArch Intern Med.(2006 Jun 26)
  52. ^Cheung AM, Tile L, Lee Y, Tomlinson G, Hawker G, Scher J, Hu H, Vieth R, Thompson L, Jamal S, Josse RVitamin K supplementation in postmenopausal women with osteopenia (ECKO trial): a randomized controlled trialPLoS Med.(2008 Oct 14)
  53. ^Emaus N, Gjesdal CG, Almås B, Christensen M, Grimsgaard AS, Berntsen GK, Salomonsen L, Fønnebø VVitamin K2 supplementation does not influence bone loss in early menopausal women: a randomised double-blind placebo-controlled trialOsteoporos Int.(2010 Oct)
  54. ^Knapen MH, Drummen NE, Smit E, Vermeer C, Theuwissen EThree-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy postmenopausal womenOsteoporos Int.(2013 Sep)
  55. ^Sasaki N, Kusano E, Takahashi H, Ando Y, Yano K, Tsuda E, Asano YVitamin K2 inhibits glucocorticoid-induced bone loss partly by preventing the reduction of osteoprotegerin (OPG)J Bone Miner Metab.(2005)
  56. ^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 YLow-dose vitamin K2 (MK-4) supplementation for 12 months improves bone metabolism and prevents forearm bone loss in postmenopausal Japanese womenJ Bone Miner Metab.(2013 May 24)
  57. ^Nowak JK, Grzybowska-Chlebowczyk U, Landowski P, Szaflarska-Poplawska A, Klincewicz B, Adamczak D, Banasiewicz T, Plawski A, Walkowiak JPrevalence and correlates of vitamin K deficiency in children with inflammatory bowel diseaseSci Rep.(2014 Apr 24)
  58. ^Jagannath VA, Fedorowicz Z, Thaker V, Chang ABVitamin K supplementation for cystic fibrosisCochrane Database Syst Rev.(2013 Apr 30)
  59. ^Nakajima S, Iijima H, Egawa S, Shinzaki S, Kondo J, Inoue T, Hayashi Y, Ying J, Mukai A, Akasaka T, Nishida T, Kanto T, Tsujii M, Hayashi NAssociation of vitamin K deficiency with bone metabolism and clinical disease activity in inflammatory bowel diseaseNutrition.(2011 Oct)
  60. ^Booth SL, Pennington JA, Sadowski JAFood sources and dietary intakes of vitamin K-1 (phylloquinone) in the American diet: data from the FDA Total Diet StudyJ Am Diet Assoc.(1996 Feb)
  61. ^Shiratori T, Sato A, Fukuzawa M, Kondo N, Tanno SSevere Dextran-Induced Anaphylactic Shock during Induction of Hypertension-Hypervolemia-Hemodilution Therapy following Subarachnoid HemorrhageCase Rep Crit Care.(2015)
  62. ^Riegert-Johnson DL, Volcheck GWThe incidence of anaphylaxis following intravenous phytonadione (vitamin K1): a 5-year retrospective reviewAnn Allergy Asthma Immunol.(2002 Oct)
  63. ^Bullen AW, Miller JP, Cunliffe WJ, Losowsky MSSkin reactions caused by vitamin K in patients with liver diseaseBr J Dermatol.(1978 May)
  64. ^Institute of Medicine (US) Panel on MicronutrientsDietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc
  65. ^Fu X, Shen X, Finnan EG, Haytowitz DB, Booth SLMeasurement of Multiple Vitamin K Forms in Processed and Fresh-Cut Pork Products in the U.S. Food SupplyJ Agric Food Chem.(2016 Jun 8)
  66. ^Manoury E, Jourdon K, Boyaval P, Fourcassié PQuantitative measurement of vitamin K2 (menaquinones) in various fermented dairy products using a reliable high-performance liquid chromatography methodJ Dairy Sci.(2013 Mar)
  67. ^Kamao M, Suhara Y, Tsugawa N, Uwano M, Yamaguchi N, Uenishi K, Ishida H, Sasaki S, Okano TVitamin K content of foods and dietary vitamin K intake in Japanese young womenJ Nutr Sci Vitaminol (Tokyo).(2007 Dec)
  68. ^Elder SJ, Haytowitz DB, Howe J, Peterson JW, Booth SLVitamin k contents of meat, dairy, and fast food in the u.s. DietJ Agric Food Chem.(2006 Jan 25)
  69. ^Shimogawara K, Muto SPurification of Chlamydomonas 28-kDa ubiquitinated protein and its identification as ubiquitinated histone H2BArch Biochem Biophys.(1992 Apr)
  70. ^Hirauchi K, Sakano T, Notsumoto S, Nagaoka T, Morimoto A, Fujimoto K, Masuda S, Suzuki YMeasurement of K vitamins in animal tissues by high-performance liquid chromatography with fluorimetric detectionJ Chromatogr.(1989 Dec 29)
  71. ^Chen GC, Wang Y, Tong X, Szeto IMY, Smit G, Li ZN, Qin LQCheese consumption and risk of cardiovascular disease: a meta-analysis of prospective studiesEur J Nutr.(2017 Dec)
  72. ^Villines TC, Hatzigeorgiou C, Feuerstein IM, O'Malley PG, Taylor AJVitamin K1 intake and coronary calcificationCoron Artery Dis.(2005 May)
  73. ^Hao G, Zhang B, Gu M, Chen C, Zhang Q, Zhang G, Cao XVitamin K intake and the risk of fractures: A meta-analysisMedicine (Baltimore).(2017 Apr)
Examine Database References
  1. Bone Mineral Density - Iwamoto I, Kosha S, Noguchi S, Murakami M, Fujino T, Douchi T, Nagata YA longitudinal study of the effect of vitamin K2 on bone mineral density in postmenopausal women a comparative study with vitamin D3 and estrogen-progestin therapyMaturitas.(1999 Jan 4)
  2. Bone Mineral Density - Braam LA, Knapen MH, Geusens P, Brouns F, Vermeer CFactors affecting bone loss in female endurance athletes: a two-year follow-up studyAm J Sports Med.(2003 Nov-Dec)
  3. Bone Mineral Density - Knapen MH, Schurgers LJ, Vermeer CVitamin K2 supplementation improves hip bone geometry and bone strength indices in postmenopausal womenOsteoporos Int.(2007 Jul)
  4. Bone Mineral Density - 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 YLow-dose vitamin K2 (MK-4) supplementation for 12 months improves bone metabolism and prevents forearm bone loss in postmenopausal Japanese womenJ Bone Miner Metab.(2013 May 24)
  5. Bone Mineral Density - Binkley N, Harke J, Krueger D, Engelke J, Vallarta-Ast N, Gemar D, Checovich M, Chappell R, Suttie JVitamin K treatment reduces undercarboxylated osteocalcin but does not alter bone turnover, density, or geometry in healthy postmenopausal North American womenJ Bone Miner Res.(2009 Jun)
  6. Bone Mineral Density - Booth SL, Dallal G, Shea MK, Gundberg C, Peterson JW, Dawson-Hughes BEffect of vitamin K supplementation on bone loss in elderly men and womenJ Clin Endocrinol Metab.(2008 Apr)
  7. Bone Mineral Density - Knapen MH, Drummen NE, Smit E, Vermeer C, Theuwissen EThree-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy postmenopausal womenOsteoporos Int.(2013 Sep)
  8. Bone Mineral Density - Shea MK, Dallal GE, Dawson-Hughes B, Ordovas JM, O'Donnell CJ, Gundberg CM, Peterson JW, Booth SLVitamin K, circulating cytokines, and bone mineral density in older men and womenAm J Clin Nutr.(2008 Aug)
  9. Bone Mineral Density - Ushiroyama T, Ikeda A, Ueki MEffect of continuous combined therapy with vitamin K(2) and vitamin D(3) on bone mineral density and coagulofibrinolysis function in postmenopausal womenMaturitas.(2002 Mar 25)
  10. Bone Mineral Density - Nishiguchi S, Shimoi S, Kurooka H, Tamori A, Habu D, Takeda T, Kubo SRandomized pilot trial of vitamin K2 for bone loss in patients with primary biliary cirrhosisJ Hepatol.(2001 Oct)
  11. Liver Cancer Risk - Ishizuka M, Kubota K, Shimoda M, Kita J, Kato M, Park KH, Shiraki TEffect of menatetrenone, a vitamin k2 analog, on recurrence of hepatocellular carcinoma after surgical resection: a prospective randomized controlled trialAnticancer Res.(2012 Dec)
  12. Liver Cancer Risk - Toshihiko Mizuta, Iwata Ozaki, Yuichiro Eguchi, Tsutomu Yasutake, Seiji Kawazoe, Kazuma Fujimoto, Kyosuke YamamotoThe effect of menatetrenone, a vitamin K2 analog, on disease recurrence and survival in patients with hepatocellular carcinoma after curative treatment: a pilot studyCancer.(2006 Feb 15)
  13. Fracture Risk - Shiraki M, Shiraki Y, Aoki C, Miura MVitamin K2 (menatetrenone) effectively prevents fractures and sustains lumbar bone mineral density in osteoporosisJ Bone Miner Res.(2000 Mar)
  14. Bone Mineral Density - Forli L, Bollerslev J, Simonsen S, Isaksen GA, Kvamsdal KE, Godang K, Gadeholt G, Pripp AH, Bjortuft ODietary vitamin K2 supplement improves bone status after lung and heart transplantationTransplantation.(2010 Feb 27)
  15. Bone Mineral Density - Purwosunu Y, Muharram, Rachman IA, Reksoprodjo S, Sekizawa AVitamin K2 treatment for postmenopausal osteoporosis in IndonesiaJ Obstet Gynaecol Res.(2006 Apr)
  16. Bone Mineral Density - Sasaki N, Kusano E, Takahashi H, Ando Y, Yano K, Tsuda E, Asano YVitamin K2 inhibits glucocorticoid-induced bone loss partly by preventing the reduction of osteoprotegerin (OPG)J Bone Miner Metab.(2005)
  17. Bone Mineral Density - Braam LA, Knapen MH, Geusens P, Brouns F, Hamulyák K, Gerichhausen MJ, Vermeer CVitamin K1 supplementation retards bone loss in postmenopausal women between 50 and 60 years of ageCalcif Tissue Int.(2003 Jul)
  18. Estrogen - Ozuru R, Sugimoto T, Yamaguchi T, Chihara KTime-dependent effects of vitamin K2 (menatetrenone) on bone metabolism in postmenopausal womenEndocr J.(2002 Jun)
  19. Glycemic Control - Hyung Jin Choi, MD, Juyoun Yu, BS, Hosanna Choi, BS, Jee Hyun An, MD, Sang Wan Kim, MD, PHD, Kyong Soo Park, MD, PHD, Hak C. Jang, MD, PHD, Seong Yeon Kim, MD, PHD and Chan Soo Shin, MD, PHDVitamin K2 Supplementation Improves Insulin Sensitivity via Osteocalcin Metabolism: A Placebo-Controlled Trial2011.()
  20. Insulin - Sakamoto N, Nishiike T, Iguchi H, Sakamoto KPossible effects of one week vitamin K (menaquinone-4) tablets intake on glucose tolerance in healthy young male volunteers with different descarboxy prothrombin levelsClin Nutr.(2000 Aug)
  21. Erythema - W W Lou, A T Quintana, R G Geronemus, M C GrossmanEffects of topical vitamin K and retinol on laser-induced purpura on nonlesional skinDermatol Surg.(1999 Dec)
  22. Erythema - Cohen JL, Bhatia ACThe role of topical vitamin K oxide gel in the resolution of postprocedural purpuraJ Drugs Dermatol.(2009 Nov)
  23. Bruising - Shah NS, Lazarus MC, Bugdodel R, Hsia SL, He J, Duncan R, Baumann LThe effects of topical vitamin K on bruising after laser treatmentJ Am Acad Dermatol.(2002 Aug)
  24. Bruising - Kovács RK, Bodai L, Dobozy A, Kemény LLack of the effect of topical vitamin K on bruising after mechanical injuryJ Am Acad Dermatol.(2004 Jun)