What is Vitamin K2 (menaquinone)?

Vitamin K2 is a fat-soluble vitamin in the vitamin K family. It helps activate proteins that regulate where calcium is used in the body.

What are the main benefits of Vitamin K2?

Vitamin K2 supports bone health by activating osteocalcin, which helps bind calcium to bone. It also supports cardiovascular health by activating matrix Gla protein (MGP), which helps inhibit arterial calcification.

What is the difference between MK-4 and MK-7?

MK-4 and MK-7 are different forms of Vitamin K2. They differ in food sources and how long they remain active in the body.

What foods contain Vitamin K2?

Vitamin K2 is found in fermented foods and some animal products. Examples include natto and certain cheeses, as well as foods like egg yolks and liver.

What is a typical Vitamin K2 dosage?

Common supplemental amounts are often in the 100–200 mcg range. Individual needs can vary based on diet, health status, and medications.

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Vitamin K2

Moderate study situation·7/10

A higher score indicates better study conditions, but not necessarily effectiveness.

Vitamin K2 (menaquinone) is a fat-soluble vitamin important for bone and cardiovascular health by regulating calcium metabolism.

Cardiovascular Support Essential Nutrient Bone Health

dose range

100–200 µg

once daily

Consumption

Take with a fat-containing meal to aid absorption.

Fat-soluble: take with fat.

Best time

Take at the first or second meal of the day to match typical dietary patterns.

Description

Vitamin K2 (menaquinone) is primarily found in fermented foods and animal products. It stands out from Vitamin K1 by playing a more distinct role in calcium metabolism, bone mineralization, and inhibiting arterial calcification. Its forms include MK-4 and MK-7.

benefits

Main effects with level of evidence

Moderate

Note on evidence

There is moderate-quality human evidence supporting Vitamin K2's benefit for bone health and arterial calcification, with strong mechanistic rationale but variable study results for some endpoints.

Supports bone health and density

Moderate

Vitamin K2 activates osteocalcin, promoting calcium binding to bone, improving bone mineral density and reducing fracture risk, particularly in postmenopausal women.

Particularly relevant for: Older adults · Postmenopausal women · Individuals at osteoporosis risk

2 · PubMed: Menaquinone-7 supplementation and fracture risk 1 · NIH Office of Dietary Supplements 6 · Examine.com: Vitamin K2

Promotes arterial flexibility and cardiovascular health

Moderate

K2 activates matrix Gla protein (MGP), which inhibits arterial calcification, and higher K2 intake is linked to reduced coronary heart disease mortality.

Particularly relevant for: Older adults · People at risk of heart disease

3 · PubMed: Intake of menaquinone associated with reduced coronary heart disease risk 1 · NIH Office of Dietary Supplements 6 · Examine.com: Vitamin K2

Optimizes calcium utilization and dental health

Limited

Vitamin K2 directs calcium to bones and teeth, preventing inappropriate deposition in soft tissues; may support gum and dental health.

Particularly relevant for: General population · Individuals concerned with dental health

1 · NIH Office of Dietary Supplements 6 · Examine.com: Vitamin K2

Safety & Information

Important safety information & known risks

For educational purposes only • not medical advice

Generally safe for most individuals at typical doses, but interacts significantly with blood thinners and in those with bleeding disorders.

warning notices

Vitamin K2 is non-toxic at recommended supplemental intakes and has no established upper limit.
Primary risk involves interaction with anticoagulant medications, which may be significant and require close monitoring.
Do not use without clinician supervision if taking anticoagulant medications like warfarin, as Vitamin K2 can interfere with their effect.
Avoid if you have known vitamin K hypersensitivity or severe bleeding disorders without medical monitoring.
Monitor coagulation status if you have liver disease and are supplementing with Vitamin K2.

Known interactions with medications

warfarin
acenocoumarol
other vitamin K antagonist anticoagulants

Contraindications / special precautions

Active anticoagulant therapy without monitoring
Known hypersensitivity to vitamin K
Severe bleeding disorders

interactions

Important interactions between active ingredient ↔ supplement / medication / food

Vitamin K2 interacts potently with anticoagulant medications and should be monitored if combined with other agents affecting blood clotting.

Avoid use with warfarin or similar anticoagulants.

drug · warfarin

AvoidStrong

Why

Vitamin K2 can reduce the efficacy of blood thinners, increasing clotting risk.

recommendation

Do not supplement Vitamin K2 without clinical monitoring if you are taking warfarin or similar drugs.

1 · NIH Office of Dietary Supplements 4 · WebMD: Vitamin K

mechanisms of action

Brief explanations of how it works

Activation of vitamin K-dependent proteins

K2 acts as a cofactor for gamma-carboxylation of proteins like osteocalcin and MGP, which regulate bone mineralization and inhibit arterial calcification.

1 · NIH Office of Dietary Supplements 2 · PubMed: Menaquinone-7 supplementation and fracture risk 3 · PubMed: Intake of menaquinone associated with reduced coronary heart disease risk