Vitamin K2 MK-7 and D3: What Is the Difference?

Vitamin K2 MK-7 and vitamin D3 are often combined in dietary supplements, but they are not the same nutrient and do not perform identical functions.

Vitamin D3 is best known for helping the body absorb calcium and supporting healthy bones, muscles, and immune function. Vitamin K2 supports proteins involved in normal blood clotting, bone metabolism, and the body’s proper use of calcium.

Understanding the difference between vitamin K2 MK-7 and D3 can help you make a more informed decision when comparing supplements.

What Is Vitamin D3?

Vitamin D3, also called cholecalciferol, is one of the two primary forms of vitamin D found in dietary supplements. The other form is vitamin D2, or ergocalciferol.

The body can naturally produce vitamin D3 when skin is exposed to sunlight. It is also available through certain foods, fortified foods, and dietary supplements.

One of vitamin D3’s most important functions is supporting the absorption of calcium in the digestive tract. Calcium is essential for normal bone mineralization, but the body needs sufficient vitamin D to absorb and use it effectively.

Vitamin D3 also supports:

• Healthy bones and teeth

• Normal muscle function

• Immune-system function

• Healthy calcium and phosphorus levels

• Normal neuromuscular function

The National Institutes of Health explains that vitamin D promotes calcium absorption and helps maintain calcium and phosphate concentrations needed for normal bone mineralization.

What Is Vitamin K2?

Vitamin K is a family of fat-soluble nutrients. Its two primary nutritional forms are vitamin K1 and vitamin K2.

Vitamin K1, also known as phylloquinone, is found primarily in green leafy vegetables. Vitamin K2 refers to a group of compounds called menaquinones. These are identified by names such as MK-4, MK-7, and MK-9.

Vitamin K is required for the activation of several vitamin K-dependent proteins. These proteins participate in normal blood clotting, bone metabolism, and other physiological functions.

According to the NIH Vitamin K fact sheet, vitamin K functions as a coenzyme needed for proteins involved in blood clotting and bone metabolism.

What Does MK-7 Mean?

MK-7 stands for menaquinone-7, a specific form of vitamin K2.

The “7” refers to the length of the molecule’s side chain. This structural difference affects how the vitamin is absorbed, transported, and retained in the body.

MK-7 remains available in the bloodstream longer than some shorter-chain forms of vitamin K. This is one reason it is frequently selected for daily K2 supplements.

Research has found that relatively low daily amounts of MK-7 can improve the activation of osteocalcin, a vitamin K-dependent protein associated with normal bone mineralization. However, this does not mean MK-7 supplements have been proven to prevent or treat osteoporosis or cardiovascular disease.

What Is the Difference Between Vitamin K2 MK-7 and D3?

The simplest difference is that vitamin D3 primarily supports calcium absorption, while vitamin K2 supports proteins involved in the body’s use of calcium.

Vitamin D3

• Is a form of vitamin D

• Supports calcium absorption

• Supports healthy bones and teeth

• Supports muscle function

• Supports normal immune-system function

• Is measured in micrograms and International Units

Vitamin K2 MK-7

• Is a form of vitamin K

• Supports vitamin K-dependent proteins

• Supports normal bone metabolism

• Supports the body’s proper use of calcium

• Participates in normal blood clotting

• Is usually measured in micrograms

Although they are different vitamins, their roles intersect through calcium metabolism and bone health.

How Do Vitamin D3 and K2 Work Together?

Vitamin D3 helps increase the body’s ability to absorb calcium from food and supplements. Vitamin K2 helps activate proteins that participate in the body’s proper use of calcium.

One of these proteins is osteocalcin, which is produced by bone-forming cells and requires vitamin K-dependent activation. Another is matrix Gla protein, a vitamin K-dependent protein studied for its role in normal calcium regulation in vascular tissues.

This complementary relationship is why vitamin D3 and K2 are frequently included in the same supplement.

A review indexed by PubMed concluded that available animal and human evidence supports continued investigation of vitamins D and K together for bone and cardiovascular health. However, researchers also emphasized the need for additional clinical studies.

A separate systematic review and meta-analysis found that combined vitamin D and K supplementation improved certain measures related to bone mineral density and osteocalcin. These findings are promising, but they do not establish that every person needs both supplements or that the combination prevents disease.

Is Vitamin D3 Effective Without K2?

Yes. Vitamin D3 still performs its normal functions when taken without a K2 supplement.

Vitamin D3 does not become ineffective simply because supplemental K2 is absent. People can obtain vitamin K through food, and individual dietary intake and nutritional needs vary considerably.

There is currently no universal medical recommendation stating that everyone who takes vitamin D3 must also take vitamin K2.

However, people looking for complementary nutritional support for calcium metabolism and bone health may choose a formula containing both vitamins. The decision should consider dietary intake, vitamin D blood levels, medications, health conditions, and professional recommendations.

Why Is MK-7 Frequently Used Instead of MK-4?

MK-4 and MK-7 are both forms of vitamin K2, but they behave differently in the body.

MK-4 has a shorter period of circulation. MK-7 generally remains available in the bloodstream longer, which makes it suitable for once- or twice-daily supplement formulations.

The longer circulation time of MK-7 does not automatically make every MK-7 supplement superior. Product quality, ingredient amounts, manufacturing standards, other ingredients, and the needs of the individual also matter.

What Are the Potential Benefits of Combining K2 MK-7 and D3?

Vitamin K2 MK-7 and D3 may provide complementary nutritional support in several areas.

Bone health

Vitamin D3 supports calcium absorption and normal bone mineralization. Vitamin K2 supports the activation of proteins involved in bone metabolism.*

Calcium utilization

D3 helps the body absorb calcium, while K2 supports proteins involved in how calcium is used within the body.*

Immune function

Vitamin D plays a recognized role in normal immune-system function.*

Muscle function

Vitamin D is involved in normal muscle and neuromuscular function.*

Cardiovascular support

Vitamin K-dependent proteins are being studied for their role in vascular health and calcium regulation. Current research is promising, but K2 supplements should not be presented as treatments for cardiovascular disease.*

What Foods Contain Vitamin D3?

Food sources of vitamin D are relatively limited. Sources include:

• Fatty fish such as salmon, trout, and mackerel

• Fish-liver oils

• Egg yolks

• Beef liver

• Fortified milk

• Fortified plant-based beverages

• Fortified breakfast cereals

Sun exposure can also contribute to vitamin D production, although season, latitude, age, skin pigmentation, sunscreen use, clothing, and time spent outdoors can affect production.

What Foods Contain Vitamin K2?

Vitamin K2 is found in varying amounts in fermented foods and certain animal-derived foods.

Potential sources include:

• Natto

• Certain aged cheeses

• Fermented foods

• Egg yolks

• Liver

• Meat and poultry

The amount and form of vitamin K2 can vary considerably between foods. Vitamin K1 from leafy green vegetables also contributes to overall vitamin K intake.

How Much Vitamin D3 and K2 Should You Take?

There is no universally accepted vitamin D3-to-K2 ratio that is appropriate for everyone.

Vitamin D needs can vary based on:

• Current vitamin D blood level

• Age

• Diet

• Sun exposure

• Skin pigmentation

• Geographic location

• Body composition

• Medical conditions

• Prescription medications

• Other supplements being used

The most common blood test used to evaluate vitamin D status measures serum 25-hydroxyvitamin D.

The general adult tolerable upper intake level for vitamin D is 4,000 IU daily. Higher amounts may be recommended in specific circumstances under professional guidance. High-potency vitamin D supplements should therefore be used thoughtfully, particularly when combined with other products containing vitamin D or calcium.

Choosing a Vitamin K2 + D3 Supplement

When comparing K2 and D3 supplements, look beyond the front label. Check the Supplement Facts and product information for:

• Amount of vitamin D3 per capsule

• Amount of vitamin K2 per capsule

• Form of vitamin K2, such as MK-7

• Suggested daily use

• Total daily intake

• Number of capsules per bottle

• Number of daily servings

• Other ingredients

• Capsule or softgel material

• Manufacturing standards

• Clear medication and safety information

Bob’s Best offers a Vitamin K2 + D3 Supplement with 5,000 IU of D3 and 100 mcg of K2 MK-7 per capsule. Each bottle contains 60 veggie capsules and provides a 30-day supply when taken at the suggested use of two capsules daily.

The suggested daily use supplies 10,000 IU of vitamin D3 and 200 mcg of K2 MK-7, making it a high-potency formula. Consult a qualified healthcare professional to determine whether this amount is appropriate for your individual needs.

Who Should Consult a Healthcare Professional First?

Speak with a qualified healthcare professional before using a K2 and D3 supplement if you:

• Take warfarin or another vitamin K antagonist

• Take another supplement containing vitamin D

• Take a calcium supplement

• Have elevated calcium or vitamin D levels

• Have kidney disease or a history of kidney stones

• Have a chronic medical condition

• Take prescription medication

• Are pregnant or nursing

Vitamin K2 can affect the action of warfarin and similar vitamin K antagonist medications. People using these medications should not begin, discontinue, or significantly change their vitamin K intake without guidance from the professional managing their anticoagulant treatment.

Frequently Asked Questions

Is vitamin K2 the same as vitamin D3?

No. Vitamin K2 and vitamin D3 are different fat-soluble vitamins. D3 supports calcium absorption, bones, muscles, and immune function. K2 supports vitamin K-dependent proteins involved in blood clotting, bone metabolism, and the body’s proper use of calcium.

What does MK-7 mean in a K2 supplement?

MK-7 means menaquinone-7. It is a long-chain form of vitamin K2 that remains available in the bloodstream longer than some shorter-chain forms.

Is MK-7 better than MK-4?

MK-7 remains in circulation longer and is commonly used in daily supplements. MK-4 has different characteristics and has also been studied extensively. The most appropriate form depends on the product, dosage, intended use, and individual needs.

Do you have to take K2 with vitamin D3?

No universal guideline requires everyone taking vitamin D3 to take supplemental K2. The vitamins have complementary roles, but individual needs depend on diet, health status, medications, and professional advice.

Can vitamin K2 remove calcium from arteries?

Vitamin K-dependent proteins are involved in normal calcium regulation, but a K2 supplement should not be described as removing existing arterial calcium or treating cardiovascular disease. Research into K2 and vascular health is ongoing.

Can you take vitamin K2 MK-7 and D3 at the same time?

These nutrients are commonly combined in the same dietary supplement. Follow the directions for the specific product and consult a healthcare professional when using a high-potency formula.

Does vitamin K2 interfere with blood thinners?

Vitamin K can interfere with warfarin and other vitamin K antagonist medications. It does not interact with every medication commonly called a blood thinner in the same way. Anyone using prescription medication should discuss new supplements with a qualified healthcare professional.

How do you know if you need vitamin D3?

A serum 25-hydroxyvitamin D blood test can help evaluate vitamin D status. A healthcare professional can interpret the result along with health history, diet, sun exposure, medications, and other relevant factors.

The Bottom Line

Vitamin K2 MK-7 and vitamin D3 are different nutrients with complementary roles.

Vitamin D3 supports calcium absorption, healthy bones, normal muscle function, and immune-system function. Vitamin K2 MK-7 supports vitamin K-dependent proteins involved in bone metabolism, normal blood clotting, and the body’s proper use of calcium.*

They are frequently combined because their functions overlap in calcium and bone metabolism. However, there is no single dosage or D3-to-K2 ratio that is ideal for everyone.

If you are looking for a high-potency formula, learn more about Bob’s Best K2 + D3 with MK-7, including its complete Supplement Facts, suggested use, safety information, and 90-day guarantee.

References and Further Reading

• NIH Office of Dietary Supplements: Vitamin D Fact Sheet for Health Professionals

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

• The Synergistic Interplay Between Vitamins D and K for Bone and Cardiovascular Health

• Combination Effect of Vitamin K and Vitamin D on Human Bone Quality

• Low-Dose Daily Intake of Vitamin K2 MK-7 and Osteocalcin Activation

*These statements have not been evaluated by the Food and Drug Administration. Dietary supplements are not intended to diagnose, treat, cure, or prevent any disease. This article is provided for general educational purposes and is not a substitute for personalized medical advice.