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Vitamin

Vitamin K2

Vitamin K2 is a family of fat-soluble menaquinones, made by bacteria and found in fermented foods such as natto and cheese. With K1, it is a main natural form of vitamin K.

Also listed as Vitamin K-2, Vitamin K, Phylloquinone, Menaquinone

Bone & JointEssential HealthCardiovascularOrgan Function

Does K2 prevent fractures?

A 2022 review pooled 16 randomized trials involving 6,425 participants. Lumbar spine bone density improved, but the combined fracture analysis from six trials did not show a significant reduction. 1

Removing one heterogeneous study changed the fracture result in favor of K2. That sensitivity matters: the conclusion depends on which trials are included, rather than offering a settled promise of protection. 1

Bone densityMixed

Bone-density findings are encouraging in postmenopausal osteoporosis; fracture prevention is less secure. 1

What does adding vitamin D change?

Eight trials with 971 participants found improved total bone density with combined vitamins K and D. A marker of incompletely activated osteocalcin also fell. These results concern a combination and intermediate measurements, so they cannot establish the independent benefit of K or a reduction in fractures. 2

Essential HealthToo little evidence

Combination studies support further investigation, not a general preventive benefit for everyone. 2

Can K keep calcium out of arteries?

Vitamin K-dependent matrix Gla protein is one reason researchers study arterial calcification. Observational findings are promising, but supplementation trials remain inconclusive. 3

Questions outside this review

This page does not assess liver health, inflammation, cholesterol or blood pressure.

Effects by health goal

Open an effect to see the studies behind its rating. Bars show the size of the effect; the letter grades the evidence.

Cardiovascular2 effects

Blood pressureCardiovascularSmallCNo linked study

No study is linked to this rating.

Rated by SuppCo · medium confidenceEvidence record

Cholesterol balanceCardiovascularSmallCNo linked study

No study is linked to this rating.

Rated by SuppCo · medium confidenceEvidence record

Organ Function1 effect

Liver healthOrgan FunctionSmallCNo linked study

No study is linked to this rating.

Rated by SuppCo · medium confidenceEvidence record

Other effects1 effect

InflammationSmallCNo linked study

No study is linked to this rating.

Rated by SuppCo · medium confidenceEvidence record

All studies

6 publications are linked to Vitamin K2, newest first.

Vitamin K2 in Health and Disease: A Clinical Perspective2024Efficacy of vitamin K2 in the prevention and treatment of postmenopausal osteoporosis: A systematic review and meta-analysis of randomized controlled trials2022The combination effect of vitamin K and vitamin D on human bone quality: a meta-analysis of randomized controlled trials.2020Quantifying dietary vitamin K and its link to cardiovascular health: a narrative review.2020Vitamin K as a Diet Supplement with Impact in Human Health: Current Evidence in Age-Related Diseases2020Vitamin K2 (Menatetrenone) Effectively Prevents Fractures and Sustains Lumbar Bone Mineral Density in Osteoporosis2000

Sources

  3. Vitamin K: Fact Sheet for Health Professionals NIH Office of Dietary Supplements