Vitamin K2
(as MK7)
The cellular calcium director supporting bone density, cardiovascular health, and vascular integrity
Menaquinone-7 (MK-7) is a long-chain form of vitamin K2 with superior bioavailability and an extended half-life that allows it to circulate for up to 72 hours. This fat-soluble vitamin activates calcium-regulating proteins, directing minerals to bones and teeth while preventing arterial calcification, making it critical for bone strength, cardiovascular health, and metabolic function across multiple organ systems.
Vitamin K2 (MK-7) has robust clinical evidence for bone health (multiple meta-analyses showing 56–81% fracture risk reduction), cardiovascular protection (multiple RCTs demonstrating arterial stiffness reduction), glycemic control (strong RCT evidence), and periodontal health. Limited human clinical trial evidence exists for cognitive function, cancer prevention, and neuropathy, though animal and mechanistic studies are compelling. No serious adverse effects documented across 40+ human clinical trials with doses up to 462 µg/day. CRN Foundation established 375 µg/day as the safe supplemental intake level based on this evidence base. MK-7 is arguably one of the most well-studied micronutrient supplemental forms available.
Bone Health and Fracture Prevention
StrongMK-7 activates osteocalcin through gamma-carboxylation, enabling calcium binding to bone mineral matrix. A landmark 3-year RCT (n=244 postmenopausal women) found MK-7 at 180 µg/day improved arterial stiffness and bone strength. Meta-analysis shows vitamin K reduces vertebral fractures by 60%, hip fractures by 77%, and non-vertebral fractures by 81% in Japanese populations. Long-term MK-7 supplementation prevents age-related BMD decline at lumbar spine and femoral neck while promoting bone quality independent of density changes.
Cardiovascular Health and Arterial Stiffness Reduction
StrongMK-7 activates matrix Gla protein (MGP), which inhibits vascular calcification and reduces arterial stiffness. A 3-year RCT (244 healthy postmenopausal women, 55–65 years) demonstrated that 180 µg MK-7 daily significantly improved arterial elasticity and stiffness index versus placebo. A 1-year follow-up study in 166 high-risk individuals (dp-ucMGP >400 pmol/L) showed post-menopausal women with elevated baseline vascular stiffness experienced the greatest improvements in blood pressure and pulse wave velocity. Multiple RCTs in hemodialysis, kidney transplant, and diabetic populations show 360–375 µg MK-7 reduces arterial stiffness progression, particularly in subgroups with existing vascular dysfunction.
Vascular Calcification Prevention
ModerateMK-7 acts as a cofactor for carboxylation of matrix Gla protein and osteocalcin in extrahepatic tissues, preventing pathological calcium deposition in arterial walls and heart valves. Clinical trials demonstrate MK-7 may delay or reverse vascular calcification in hemodialysis patients, kidney transplant recipients, and those with chronic kidney disease. Reduced plasma dp-ucMGP (decarboxylated, undercarboxylated MGP) levels—a marker of vitamin K deficiency—significantly correlate with improved vascular outcomes following MK-7 supplementation.
Glycemic Control and Insulin Sensitivity
StrongAn RCT (n=68 insulin-independent type 2 diabetes patients) found 360 µg MK-7 daily for 12 weeks reduced fasting plasma glucose (29% reduction) and HbA1c (12% reduction) compared to placebo. Mechanisms include osteocalcin-mediated adiponectin upregulation and anti-inflammatory NF-κB pathway inhibition. A 6-month RCT (n=60 T2DM participants) with microbiota analysis showed MK-7 improved glucose tolerance through alterations in secondary bile acids and short-chain fatty acids, mediated by MK-7-responsive bacterial genera.
Cognitive Function and Neurodegeneration Prevention
LimitedBrain MK-4 (converted from MK-7) concentrations inversely correlate with Alzheimer's pathology, neurofibrillary tangle density, and Braak stage. In aged rats, MK-7 treatment reversed age-related cognitive deficits, improved inflammatory markers, inhibited cerebrovascular calcification, increased Gas6 protein expression, and improved climbing ability. Mechanisms involve mitochondrial electron transport enhancement (ATP production), reduction in amyloid-beta neurotoxicity, suppression of pro-inflammatory cytokines (IL-6, TNF-α), and blood-brain barrier protection via protein S and Gas6 activation.
Periodontal Health
ModerateCase-control study (n=154) found significantly reduced serum MK-7 levels in periodontitis patients versus healthy controls (0.19±0.01 nmol/L in stage IV disease). VK2 levels negatively correlated with alveolar bone loss, clinical attachment loss, and bleeding on probing. MK-7 reduces osteoclast formation through NF-κB inhibition and promotes osteoblast differentiation, mechanisms directly relevant to periodontal tissue regeneration and bone preservation.
Long COVID and Inflammatory Markers
ModerateAn RCT (n=90 long COVID patients, 2:1 randomization) showed 240 µg MK-7 + 2000 IU vitamin D3 for 24 weeks reduced LC Research Index scores by 7.1%, decreased fungal translocation marker (1,3)-β-D-glucan, reduced oxidized LDL, and lowered inflammatory markers (sTNF-RI, sCD163). The intervention stabilized long COVID symptom count while controls experienced symptom increases.
Polycystic Ovary Syndrome (PCOS) Management
ModerateAn 8-week RCT (n=32 PCOS patients) found 90 µg MK-7 daily significantly reduced free androgen index (FAI), serum DHT, waist circumference, and body fat mass while increasing skeletal muscle and SHBG. Fasting insulin and HOMA-IR decreased, indicating improved insulin sensitivity. MK-7 reduced triglycerides but not other lipid parameters.
Rheumatoid Arthritis Management
ModerateMultiple studies show MK-7 and MK-4 reduce disease activity markers in RA patients through immunosuppressive and anti-inflammatory mechanisms. A cross-sectional study (100 µg MK-7 daily) showed significant reductions in DAS28-ESR, ESR, CRP, and MMP-3 after 3 months. In vitro studies demonstrate MK-7 inhibits proliferation of mitogen-activated PBMCs from RA patients with IC50 values correlating with CRP, RF, and ACPA.
Peripheral Neuropathy Relief
ModerateA larger clinical trial (200 µg MK-7 twice daily for 8 weeks in patients with vitamin B12 deficiency or type 2 diabetes) showed therapeutic activity for peripheral neuropathy symptoms including cramps, burning pain, weakness, and fatigue. Reductions persisted after discontinuation. MK-7 was well tolerated with no adverse events.
Liver Protection and Anti-Aging
LimitedVK2 administration in aging rats improved hepatic function (ALT, AST, total protein, albumin), suppressed expression of inflammatory markers (TNF-α, COX-2, iNOS) and fibrotic biomarkers (TGF-β, TIMP), reduced apoptosis, and preserved mitochondrial architecture. Mechanisms involve interception of Keap-1/Nrf-2/HO-1 aging-related signaling. VK2 also showed efficacy against hepatocellular carcinoma recurrence in clinical settings.
Mitochondrial Function and Energy Production
LimitedMK-7 functions as a mitochondrial electron carrier, enhancing ATP production and electron transport chain efficiency. In Parkinson's disease patients, one week of MK-7 treatment increased brain ATP levels compared to healthy controls. In aged rats with Parkinson's modeling, MK-7 improved mitochondrial dysfunction markers and behavioral outcomes. In 6-OHDA-damaged cells, MK-7 regulated mitophagy, mitochondrial fusion/fission balance, and promoted mitochondrial biogenesis via PINK1/Parkin signaling.
Parkinson's Disease Biomarkers
LimitedSerum VK2 levels are significantly lower in Parkinson's disease patients than healthy controls (3-fold reduction observed). Animal studies show MK-7 restores brain ATP levels and may protect against mitochondrial dysfunction characteristic of PD. A clinical trial is currently investigating MK-7 effects on cerebral ATP via 31P-MRSI in mitochondrial Parkinson's disease patients.
Multiple Sclerosis Disease Progression
LimitedSerum VK2 is 3-fold higher in healthy controls versus MS patients (median 866 ng/mL vs. 196 ng/mL). VK2 protects neurons and oligodendrocytes from oxidative injury, suppresses pro-inflammatory IL-6 via Cox2 inhibition, and reduces disease activity. Animal models show MK-4 ameliorates experimental autoimmune encephalomyelitis.
Coronary Artery Disease Risk Reduction
ModerateObservational data (Rotterdam Study) showed highest tertile dietary menaquinone intake associated with 27% lower CAD mortality risk (mid-tertile) and 57% lower risk (upper tertile) versus lowest tertile. Recent cross-sectional analysis found acute coronary syndrome patients had significantly reduced serum MK-4 and MK-7 (1.61–1.64 ng/mL vs. 2.29–2.16 ng/mL controls). MK-7 shows strongest associations with CAD risk markers; unstable angina patients showed lowest MK-7 levels.
Wound Healing Acceleration
LimitedMeta-analysis of rat models (6 studies) showed vitamin K treatment significantly increased wound healing rate (WMD 27.45, 95% CI 13.46–41.44). Clinical RCT showed vitamin K-treated wounds had significantly reduced area on day 4 versus controls, though no difference by day 7. MK-7 bioavailability and trans-isomer specificity appear crucial for efficacy.
Cancer Prevention and Treatment Support
LimitedIn vitro and in vivo studies demonstrate VK2 inhibits proliferation of hepatocellular carcinoma (HCC), leukemia, colorectal, ovarian, and pancreatic cancer cells through cell-cycle arrest and apoptosis induction. Clinical trials show VK2 reduced HCC recurrence rates and enhanced survival. Dietary VK2 intake associated with reduced prostate and lung cancer risk. Mechanisms involve NF-κB inhibition, c-MYC suppression, and activation of extrinsic apoptosis pathways.
Mental Health and Depression Symptoms
LimitedMost observational studies report inverse associations between vitamin K intake/serum levels and depressive symptoms. One small RCT (PCOS women) showed 90 µg MK-7 for 8 weeks reduced BDI-II depression scores compared to placebo. Animal studies in metabolic syndrome and estrogen-deficient rats show MK-7 reduces depression-like behaviors and anxiety-like symptoms via oxidative stress reduction and anti-inflammatory effects.
Endothelial Function Improvement
LimitedIn ApoE/LDLR-deficient atherosclerotic mice, low-dose MK-7 (0.05 mg/kg) improved acetylcholine- and flow-induced endothelium-dependent vasodilation and increased nitric oxide production. Both low and high doses reduced media thickness in brachiocephalic arteries. MK-7 improves NO-dependent endothelial function without effects on thrombogenesis.
Respiratory Function and COPD
LimitedCOPD patients show elevated dp-ucMGP levels (indicating vitamin K deficiency), inversely associated with lung diffusion capacity. Vitamin K status may protect against emphysema. Preliminary data suggest mortality is higher in COPD patients on warfarin versus direct oral anticoagulants, suggesting vitamin K's protective pulmonary role.
Ocular Health and Cataract Prevention
LimitedPREDIMED trial (n=5860) demonstrated 29% reduction in cataract surgery risk in highest tertile dietary vitamin K1 intake versus lowest. Matrix Gla protein is expressed in ocular tissues and regulates intraocular pressure. VK2 preferentially accumulates in retinal tissues via HDL transport, suggesting neuroprotective and anticalcification roles.
Muscle Mass and Sarcopenia Prevention
LimitedObservational data associates higher plasma vitamin K with better physical performance (SPPB, gait speed, leg strength). MK-7 increases satellite cell proliferation and migration in muscle tissue and improves mitochondrial energy metabolism. In muscle cells, MK-4 reduces lactate dehydrogenase and increases expression of myogenic factors, suggesting anti-atrophy potential.
Kidney Transplant Outcomes
ModerateMK-7 supplementation (360 µg/day for 8 weeks) in stable kidney transplant recipients reduced carotid-femoral pulse wave velocity by 14.2%. A 60-patient KING trial showed MK-7 significantly reduced dp-ucMGP levels and arterial stiffness markers. Vitamin K status improvements post-transplant correlate with slowed vascular calcification progression.
Acute Lung Injury Protection
LimitedIn LPS-induced acute lung injury models, high-dose VK2 pretreatment significantly downregulated pro-inflammatory (TNF-α, reduced IL-10) and pro-apoptotic markers, upregulated tight junction proteins (ZO-1, occludin), and inhibited mitochondrial dysfunction and excessive autophagy, protecting epithelial and endothelial barrier integrity.
Inflammatory Bowel Disease Risk Reduction
LimitedCross-sectional analysis (NHANES n=3591) found higher vitamin D intake reduced IBD risk 51% per 1 mcg increase. Among non-diabetic individuals, each 1 mcg vitamin K increase associated with 67% IBD risk reduction. VK2 regulates gut microbiota, reduces inflammation, modulates immune response via MGP-mediated mechanisms.
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