What is Vitamin K2 (as MK4)?

Vitamin K2 (MK4) is a fat-soluble form of vitamin K involved in activating proteins that regulate where calcium is used in the body, especially in bone and blood vessels.

What are the main benefits of Vitamin K2 (MK4)?

MK4 supports bone health by activating osteocalcin and may help limit calcium buildup in arteries by activating matrix Gla protein (MGP). It may also have modest effects on glucose metabolism, but human evidence is limited.

What is a typical dosage range for Vitamin K2 (MK4)?

Common supplemental amounts are often in the tens of milligrams; a typical range is about 45–100 mg per day. Individual needs vary, so dosing should be personalized with a clinician.

Which foods contain Vitamin K2 (MK4)?

MK4 is found mainly in animal-derived foods such as egg yolks, liver, and some dairy products, and it can also be present in certain fermented foods depending on preparation.

Who should be cautious with Vitamin K2 (MK4) supplements?

People taking vitamin K–antagonist anticoagulants (such as warfarin) should avoid changing vitamin K intake without medical supervision because it can affect medication effectiveness. Pregnant or breastfeeding individuals and those with medical conditions should consult a clinician before use.

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Vitamin K2
(as MK4)

Moderate study situation·7/10

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

Vitamin K2 (MK4) is a fat-soluble vitamin crucial for bone, vascular, and metabolic health through its role in calcium regulation.

Cardiovascular Support Essential Nutrient Bone Health Glucose Metabolism

dose range

45–100 mg

Split doses: e.g., 15 mg three times daily; higher therapeutic protocols use up to 45 mg three times daily for osteoporosis in Asia.

Consumption

Take with a fat-containing meal for optimal absorption. Consistency in daily intake is advised.

Fat-soluble: take with fat.

Best time

Take with meals; best absorbed with dietary fat. Morning and main meals are suitable.

Description

Vitamin K2, specifically in the menaquinone-4 (MK4) form, is an essential fat-soluble vitamin found in animal products and some fermented foods. It is vital for the activation of proteins involved in calcium transport, supporting bone strength and preventing vascular calcification.

benefits

Main effects with level of evidence

Moderate

Note on evidence

Clinical trials and meta-analyses support MK4’s role in bone health, with observational evidence for cardiovascular benefits. Research on metabolic effects is promising but limited.

Supports bone mineralization and density

Strong

MK4 activates osteocalcin, improving calcium binding in bone and reducing the risk of osteoporosis and fractures, particularly in postmenopausal women.

Particularly relevant for: postmenopausal women · older adults · individuals at risk for osteoporosis

1 · NIH Office of Dietary Supplements: Vitamin K Fact Sheet for Health Professionals 2 · Effect of Vitamin K2 on Bone Mineral Density in Postmenopausal Women with Osteoporosis: A Metaanalysis of Randomized Controlled Trials (PubMed)7 · Cochrane: Vitamin K supplementation for the prevention of osteoporosis in postmenopausal women 8 · Linus Pauling Institute, Oregon State University: Vitamin K

May protect against arterial calcification and cardiovascular disease

Moderate

By activating matrix Gla protein (MGP), MK4 helps prevent calcium deposition in arteries, potentially lowering the risk of atherosclerosis and heart disease.

Particularly relevant for: adults at risk of cardiovascular disease

1 · NIH Office of Dietary Supplements: Vitamin K Fact Sheet for Health Professionals 3 · Dietary intake of vitamin K and risk of coronary heart disease: The Rotterdam Study (PubMed)5 · EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the substantiation of health claims related to vitamin K2 as menaquinone-7 and maintenance of normal bone health 6 · Examine.com: Vitamin K 8 · Linus Pauling Institute, Oregon State University: Vitamin K

Potentially improves insulin sensitivity and glucose metabolism

Limited

Supplementation may modestly improve insulin sensitivity and markers of glucose metabolism, though evidence in humans is still limited.

Particularly relevant for: individuals with metabolic syndrome · type 2 diabetics

4 · Vitamin K supplementation and insulin resistance in type 2 diabetes mellitus (PubMed)6 · Examine.com: Vitamin K 8 · Linus Pauling Institute, Oregon State University: Vitamin K

Safety & Information

Important safety information & known risks

For educational purposes only • not medical advice

MK4 is generally well tolerated, but safety concerns arise with anticoagulant use or blood clotting disorders.

warning notices

No reported toxicity at clinical doses up to 135 mg/day in trials.
Rare side effects may include mild gastrointestinal discomfort.
May interfere with blood-thinning medications (vitamin K antagonists).
Avoid use with anticoagulant medications such as warfarin unless under medical supervision, due to risk of counteracting anticoagulant effects.
Use only under clinician supervision if you have a blood clotting disorder.
Monitor for possible interactions or altered efficacy if you have chronic kidney disease or are on dialysis.

Known interactions with medications

warfarin and other vitamin K antagonists

Contraindications / special precautions

known blood clotting disorders unless monitored
patients on warfarin or related medications

interactions

Important interactions between active ingredient ↔ supplement / medication / food

MK4 can reduce the efficacy of vitamin K antagonist anticoagulants and may have synergistic effects with vitamin D for bone health.

MK4 can counteract the effect of warfarin and similar anticoagulants.

drug · warfarin

AvoidStrong

Why

Vitamin K2 (MK4) activates clotting factors, potentially reversing the intended anticoagulant effects of warfarin.

recommendation

Avoid using MK4 with warfarin or similar agents unless clinical INR monitoring is in place.

1 · NIH Office of Dietary Supplements: Vitamin K Fact Sheet for Health Professionals 6 · Examine.com: Vitamin K 8 · Linus Pauling Institute, Oregon State University: Vitamin K

May have complementary effects on bone health when combined with vitamin D.

nutrient · Vitamin D

PairModerateTake together

Why

Both nutrients play roles in calcium metabolism – vitamin D increases calcium absorption while MK4 supports its correct use and deposition.

recommendation

Consider co-supplementation with vitamin D for bone health, especially in deficiency or at-risk populations.

2 · Effect of Vitamin K2 on Bone Mineral Density in Postmenopausal Women with Osteoporosis: A Metaanalysis of Randomized Controlled Trials (PubMed)6 · Examine.com: Vitamin K

mechanisms of action

Brief explanations of how it works

Gamma-carboxylation of vitamin K–dependent proteins

MK4 serves as a cofactor for the gamma-carboxylation of proteins like osteocalcin and matrix Gla protein, crucial for binding calcium in bones and preventing vascular calcification.

1 · NIH Office of Dietary Supplements: Vitamin K Fact Sheet for Health Professionals 2 · Effect of Vitamin K2 on Bone Mineral Density in Postmenopausal Women with Osteoporosis: A Metaanalysis of Randomized Controlled Trials (PubMed)3 · Dietary intake of vitamin K and risk of coronary heart disease: The Rotterdam Study (PubMed)5 · EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the substantiation of health claims related to vitamin K2 as menaquinone-7 and maintenance of normal bone health 6 · Examine.com: Vitamin K