Vitamin K2
Also sold as: Menaquinone-7 · MK-7 · Menatetrenone · MK-4
Fat-soluble menaquinones involved in vitamin K-dependent protein activation. Bone-marker and arterial-stiffness findings are more developed than evidence for fracture, heart-attack or mortality prevention.
Longevity
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Research
- Longevity: Longevity benefit is unestablished: the dossier lacks adequate hard cardiovascular-event or survival trials; this label does not imply a definitive negative mortality RCT.
REALITY CHECK // K2 is marketed as a calcium traffic controller, but a plausible mechanism does not prove arteries are cleared or that every D3 user needs K2. MK-7 microgram supplements and pharmacological 45 mg MK-4 protocols are not interchangeable, and fracture evidence remains disputed.
Levels: how we grade evidence. Grey = evidence of no benefit; amber = evidence it makes this goal worse.
Ratings are self-reported by a self-selected group of users: how it felt, not proof that it works.
Check your bottle
Compare what your label says with what was used in trials. This is a trial range, not a personal prescription.
Enter the amount from your label to see the result.
How it was studied
UPPER LIMIT // Neither EFSA nor US IOM established a numerical vitamin K UL in the dossier. Adequate-intake values are not ULs, and no UL does not establish unlimited safety. The major practical hazard is antagonism of vitamin K antagonist anticoagulants.
Summary
Meta-analyses suggest lumbar bone-density and osteocalcin-marker benefits in postmenopausal osteoporosis. Fracture evidence is uncertain and partly affected by older study-quality concerns. Arterial-stiffness signals do not show that K2 removes coronary calcium or substitutes for cardiovascular treatment.
Mechanism
Vitamin K supports gamma-carboxylation of osteocalcin, matrix Gla protein and coagulation factors. These mechanisms and carboxylation markers do not by themselves prove better survival or reversal of vascular calcification.
Typical studied dose
MK-7 studies include 180 micrograms/day (0.18 mg) for three years for arterial stiffness and 360 micrograms/day (0.36 mg) for two years in coronary disease. Clinical osteoporosis MK-4 studies commonly used 45 mg/day, a very different regimen. All calculator entries use mg: divide micrograms by 1000.
Upper limit
Neither EFSA nor US IOM established a numerical vitamin K UL in the dossier. Adequate-intake values are not ULs, and no UL does not establish unlimited safety. The major practical hazard is antagonism of vitamin K antagonist anticoagulants.
Popular stacks with Vitamin K2
Not enough stack data yet. A combination with Vitamin K2 appears here once 5 people rate the same set.
Forms and label traps
| Form on label | Active content | Studied range / day | Absorption & GI tolerance | Verdict |
|---|---|---|---|---|
| MK-7: declared menaquinone-7 mg Best for: Comparison with the exact ingredient and dose basis on the Supplement Facts panel. |
100% elemental / active | 0.18–0.36 mg | Dose basis is declared pure MK-7, not carrier/extract mass: 180–360 micrograms equals 0.18–0.36 mg in selected trials. The absorption study found longer serum persistence than MK-4; this does not establish superior hard outcomes. See the form-specific clinical note; tolerance depends on dose and medical context. |
Studied standard [LABEL // VERIFY_DOSE_BASIS] Dose basis is declared pure MK-7, not carrier/extract mass: 180–360 micrograms equals 0.18–0.36 mg in selected trials. The absorption study found longer serum persistence than MK-4; this does not establish superior hard outcomes. |
| MK-4 / menatetrenone: declared mg Best for: Comparison with the exact ingredient and dose basis on the Supplement Facts panel. |
100% elemental / active | 45–45 mg | Clinical osteoporosis studies used pharmacological 45 mg/day, often divided. Small nutritional-dose absorption results cannot justify saying dietary MK-4 is biologically useless. Do not substitute this regimen for MK-7 micrograms. See the form-specific clinical note; tolerance depends on dose and medical context. |
Caution [LABEL // VERIFY_DOSE_BASIS] Clinical osteoporosis studies used pharmacological 45 mg/day, often divided. Small nutritional-dose absorption results cannot justify saying dietary MK-4 is biologically useless. Do not substitute this regimen for MK-7 micrograms. |
Common label traps
- TRAP_01 // K2 unclogs calcified arteries
Coronary-calcium primary endpoints were largely null or mixed. Plaque subanalyses and stiffness markers cannot establish reversal or replace prescribed therapy. - TRAP_02 // D3 is unsafe unless paired with K2
Bone-marker rationale and combination studies do not establish a mandatory K2:D3 ratio or prove every unpaired D3 dose calcifies arteries. - TRAP_03 // MK-4 and MK-7 doses are interchangeable
They differ in kinetics and trial regimens. 180 micrograms MK-7 is 0.18 mg; 45 mg MK-4 is a pharmacological exposure.
Other outcomes studied
Outside the five leaderboard goals. Same evidence levels as above.
- POSTMENOPAUSAL BONE DENSITY Moderate · benefit
Meta-analyses show lumbar BMD and undercarboxylated osteocalcin improvements; one menatetrenone analysis reports BMD +0.05 g/cm2 (95% CI 0.01–0.09). Many trials use 45 mg MK-4, not ordinary MK-7 supplements.
PMID 36033779 PMID 30734066 PMID 41268154 - FRACTURES Limited · benefit
Older meta-analysis suggested fewer fractures, but later assessments found uncertain or nonsignificant effects. Study-quality problems and retractions in parts of the older literature require sensitivity review.
PMID 16801507 PMID 19818211 PMID 30734066 - ARTERIAL STIFFNESS Limited · benefit
180 micrograms/day MK-7 for three years improved stiffness measures in postmenopausal women, especially with higher baseline stiffness. This surrogate is not an infarction or survival endpoint.
PMID 25694037 PMID 40077685 - CORONARY CALCIFICATION Limited · no benefit
The dossier reports the two-year 360-microgram/day CAD trial had no significant primary CAC benefit; exploratory noncalcified-plaque findings cannot establish reversal. Dialysis results are also mixed.
PMID 42268593 PMID 35641194 PMID 31704740 - TEETH / PERIODONTIUM No established evidence
Periodontal-cell and rat findings are preclinical. No human cavity or plaque RCT benefit is indexed.
PMID 33517171 PMID 25569194 - DEPRESSION Limited · benefit
Exploratory observational associations do not prove supplementation treats depression.
PMID 40428819
Reader questions
How much K2 should accompany my vitamin D?
No universally validated ratio is established. Combination evidence concerns selected bone populations; it does not prove that every D3 user must add K2.
Why are MK-4 doses so much larger?
Their kinetics and clinical protocols differ. MK-7 180 micrograms is 0.18 mg; osteoporosis MK-4 studies commonly used 45 mg. Those regimens must not be interchanged.
Can MK-7 cause palpitations?
The dossier contains anecdotal reports without a confirmed RCT safety signal. New or persistent palpitations merit medical assessment rather than guessed mineral corrections.
Can K2 replace a statin or clear artery calcium?
No clinical evidence here establishes that substitution or reversal. A null primary CAC outcome must not be marketed as an unclogging effect.
Stack interactions
- Danger Warfarin / acenocoumarol [CAUTION // CLINICAL_REVIEW]
Changing vitamin K intake can weaken anticoagulation and destabilize INR. Do not start or stop K2 without the prescriber. This specific vitamin K antagonist mechanism does not apply identically to direct oral anticoagulants.
PMID 26962786 PMID 15121490 PMID 17143047 - Caution Vitamin D and calcium [CAUTION // CLINICAL_REVIEW]
Combination trials suggest bone-density benefit in selected postmenopausal populations; this is not proof of reduced cardiovascular events or a universal D3-to-K2 ratio.
PMID 32219282 PMID 11180916 - Caution Prolonged broad-spectrum antibiotics [CAUTION // CLINICAL_REVIEW]
The dossier notes reduced bacterial menaquinone synthesis; clinical relevance is more likely with poor intake or prolonged treatment. No direct trial citation is provided for this interaction. - Caution Magnesium [CAUTION // CLINICAL_REVIEW]
Magnesium supports vitamin D metabolism, but a direct pharmacological K2-magnesium interaction or proven triple-stack synergy is not established.
Red flags: interactions and who should avoid it
Interactions
Warfarin / acenocoumarol: Changing vitamin K intake can weaken anticoagulation and destabilize INR. Do not start or stop K2 without the prescriber. This specific vitamin K antagonist mechanism does not apply identically to direct oral anticoagulants. Vitamin D and calcium: Combination trials suggest bone-density benefit in selected postmenopausal populations; this is not proof of reduced cardiovascular events or a universal D3-to-K2 ratio. Prolonged broad-spectrum antibiotics: The dossier notes reduced bacterial menaquinone synthesis; clinical relevance is more likely with poor intake or prolonged treatment. No direct trial citation is provided for this interaction. Magnesium: Magnesium supports vitamin D metabolism, but a direct pharmacological K2-magnesium interaction or proven triple-stack synergy is not established.
Avoid or ask a doctor first if
Warfarin or acenocoumarol use requires prescriber-managed vitamin K intake and INR monitoring; do not start or stop K2 independently. High-dose use in pregnancy/lactation lacks sufficient evidence. New palpitations need assessment; reports after MK-7 are anecdotal, not a proven universal reaction.
Sources (PubMed, 10)
- Efficacy of vitamin K2 in the prevention and treatment of postmenopausal osteoporosis: A systematic review and meta-analysis of randomized controlled trials.
PMID 36033779 · 2022 · Systematic review / meta-analysisPostmenopausal bone-density and marker evidence, not a universal longevity claim.
- The efficacy and safety of menatetrenone in the management of osteoporosis: a systematic review and meta-analysis of randomized controlled trials.
PMID 30734066 · 2019 · Systematic review / meta-analysisMenatetrenone meta-analysis separates bone-density benefit from uncertain fractures.
- Vitamin K to prevent fractures in older women: systematic review and economic evaluation.
PMID 19818211 · 2009 · Systematic review / meta-analysisAssessment questioning certainty of fracture prevention.
- Menaquinone-7 supplementation improves arterial stiffness in healthy postmenopausal women. A double-blind randomised clinical trial.
PMID 25694037 · 2015 · Randomized controlled trialThree-year MK-7 arterial-stiffness surrogate trial.
- Two Years of Menaquinone-7 Supplementation and Coronary Artery Calcification: A Randomized Clinical Trial.
PMID 42268593 · 2026 · Randomized controlled trialTwo-year coronary calcification trial; primary endpoint reported as null in the supplied dossier.
- Comparison of menaquinone-4 and menaquinone-7 bioavailability in healthy women.
PMID 23140417 · 2012 · Randomized controlled trialSmall MK-4 versus MK-7 serum bioavailability comparison.
- Interaction Between Dietary Vitamin K Intake and Anticoagulation by Vitamin K Antagonists: Is It Really True?: A Systematic Review.
PMID 26962786 · 2016 · Systematic review / meta-analysisVitamin K intake and vitamin K antagonist anticoagulation review.
- The combination effect of vitamin K and vitamin D on human bone quality: a meta-analysis of randomized controlled trials.
PMID 32219282 · 2020 · Systematic review / meta-analysisVitamin K plus D bone-quality trial meta-analysis.
- Vitamin K2 promotes the osteogenic differentiation of periodontal ligament stem cells via the Wnt/β-catenin signaling pathway.
PMID 33517171 · 2021 · In-vitro mechanistic studyPeriodontal-cell mechanism only, not a human dental efficacy trial.
- Therapeutic effects of systemic vitamin k2 and vitamin d3 on gingival inflammation and alveolar bone in rats with experimentally induced periodontitis.
PMID 25569194 · 2015 · Animal studyRat periodontitis experiment, not human cavity prevention.
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