MK-4 vs MK-7: Which Vitamin K2 Is Better for Your Health?

Over the past decade, vitamin K2 has gained significant attention for its critical roles in supporting bone density and cardiovascular health. Yet, for many, the choice between its two main forms, MK-4 and MK-7, remains a source of confusion when selecting a supplement.

Quick Summary

A comparison of vitamin K2's forms, MK-4 and MK-7, reveals critical differences in bioavailability and half-life that impact effectiveness. MK-7 is generally considered superior for supplementation due to its longer and more stable activity in the body at standard doses.

Key Points

• MK-7 is superior for supplementation: Due to its long half-life and high bioavailability, MK-7 is the most effective form for daily supplementation.

• MK-4 requires high, frequent doses: MK-4 has a short half-life and poor bioavailability at nutritional doses, requiring very large and frequent intake for therapeutic effects.

• MK-7 provides sustained action: With a half-life of up to 72 hours, MK-7 remains in the bloodstream, ensuring a consistent supply to bones and arteries.

• MK-4 is converted in the body: Your body can convert other forms of vitamin K, including MK-7, into MK-4 for use in specific tissues like the brain.

• MK-7 is a better calcium regulator: By activating osteocalcin and MGP, MK-7 efficiently directs calcium to bones and teeth while preventing arterial calcification.

• Consider MK-7 for convenience and efficacy: The lower, once-daily dose of MK-7 makes it a more practical and effective option for long-term health support.

Understanding Vitamin K2: The Menaquinone Family

Vitamin K is a group of fat-soluble vitamins crucial for blood coagulation and calcium metabolism. Vitamin K2 (menaquinone) is particularly important for directing calcium to bones and preventing its accumulation in soft tissues. The two most common and supplemented forms of K2 are menaquinone-4 (MK-4) and menaquinone-7 (MK-7), which differ in structure, sources, and how the body uses them.

MK-4 vs. MK-7: Key Differences Explained

MK-4 is a short-chain menaquinone found in animal products and can be produced by the body. MK-7 is a long-chain menaquinone sourced mainly from fermented foods like natto and produced by bacteria.

Bioavailability and Half-Life

A key difference is how well they are absorbed and used by the body. At typical supplement doses, MK-7 is highly bioavailable and has a long half-life, staying in the body for days and providing stable levels. MK-4, however, has a very short half-life and is poorly absorbed at nutritional doses, requiring much larger and more frequent intake for any potential therapeutic effect.

Targeting Different Tissues

MK-7's excellent bioavailability allows it to reach tissues outside the liver, activating proteins like osteocalcin for bone health and Matrix-Gla Protein (MGP) for preventing arterial calcification. While the body can convert MK-7 to MK-4 for use in specific tissues like the brain, oral MK-4 supplements don't effectively reach these extra-hepatic tissues at typical doses.

Health Benefits: MK-7 vs. MK-4

The clinical effectiveness of MK-4 and MK-7 varies due to their bioavailability and dosing.

MK-7 Benefits:

• Bone Health: Its long half-life supports consistent osteocalcin activation, crucial for bone mineralization and strength.
• Cardiovascular Health: Activates MGP to help prevent arterial calcification.
• Effective at Low Doses: Achieves significant effects with a single daily dose (90-180 mcg).

MK-4 Benefits:

• High-Dose Therapeutic Use: Evidence for bone benefits primarily comes from studies using extremely high doses (45 mg/day) not practical for typical supplementation.
• Tissue-Specific Functions: Naturally found in tissues like the brain and reproductive organs, suggesting specific local roles, likely from conversion of other K forms.

Comparison Table: MK-4 vs. MK-7

Feature	Menaquinone-4 (MK-4)	Menaquinone-7 (MK-7)
Half-Life	Very short (approx. 2 hours)	Very long (approx. 72 hours or more)
Bioavailability	Poor at nutritional doses	Excellent
Dosing	Requires large, frequent doses (e.g., 45 mg/day, split)	Requires much smaller, once-daily dose (e.g., 90-180 mcg)
Primary Source	Animal products (e.g., meat, eggs, dairy)	Fermented foods (e.g., natto), bacterial synthesis
Body Accumulation	Does not accumulate in the blood at nutritional doses	Accumulates in the bloodstream for sustained activity
Effectiveness at Nutritional Doses	Limited, based on poor absorption and short half-life	High, providing consistent support for bone and heart health
Recommended for General Supplementation	Not recommended due to dosing requirements	The preferred choice for most people

Making the Best Choice for Your Needs

For most people looking to supplement, MK-7 is the better choice for supporting bone and heart health. Its high bioavailability and long half-life allow a small, once-daily dose to effectively activate key proteins. This is far more practical and reliable than the high, frequent doses of MK-4 needed for similar effects. While the body makes MK-4 for specific tissue needs, oral MK-4 supplements at nutritional levels aren't effective for general support. Choosing a high-quality MK-7 supplement provides a steady, effective supply of K2.

Conclusion

While both are vitamin K2 forms, MK-7 is superior for supplementation due to its better bioavailability and longer half-life. It provides consistent activation of proteins for bone and cardiovascular health at practical doses, unlike MK-4 which requires very high doses. For optimal vitamin K2 benefits from a supplement, MK-7 is the clear choice.

Clinical Evidence on Vitamin K2 (Menaquinone) Benefits

Frequently Asked Questions

Frequently Asked Questions

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

The main differences are their half-life and bioavailability. MK-7 is a long-chain menaquinone with a long half-life (days) and excellent bioavailability, allowing it to accumulate in the blood at low doses. MK-4 is a short-chain menaquinone with a very short half-life (hours) and poor bioavailability at nutritional doses.

Which form of vitamin K2 is best for bone health?

For supplementation purposes, MK-7 is generally considered superior for bone health. Its longer half-life ensures a consistent supply in the bloodstream to activate osteocalcin, a protein that binds calcium to bone, making it more effective for increasing bone mineral density at a lower, daily dose.

Which vitamin K2 is better for heart health?

MK-7 is the more effective form for cardiovascular health. Its superior bioavailability and prolonged presence in the body ensure the activation of Matrix-Gla Protein (MGP), which helps prevent calcium from building up in the arteries and other soft tissues.

Where do MK-4 and MK-7 come from?

MK-4 is primarily found in animal products like meat, eggs, and dairy, and is also produced in the body from other forms of vitamin K. MK-7 is produced by bacteria during the fermentation process and is found in high concentrations in natto.

What are the typical dosages for MK-4 and MK-7?

Due to its high bioavailability, an effective daily dose of MK-7 is relatively small, often between 90-180 mcg. In contrast, to achieve a therapeutic effect, MK-4 is typically used in much larger doses, sometimes up to 45 mg per day, taken multiple times.

Can I get enough vitamin K2 from food?

It is difficult to get a consistent, high dose of vitamin K2 from food alone. While some foods like natto are rich in MK-7, many people find the taste unappealing. Furthermore, MK-4 from animal products has very limited bioavailability at nutritional levels.

Is it better to take a supplement with MK-4 or MK-7?

For most people, an MK-7 supplement is the better choice. Its high absorption and long-lasting effects provide reliable and sustained benefits for both bone and heart health with a convenient once-a-day dose. MK-4 supplementation at typical doses is far less effective.

Can I take both MK-4 and MK-7?

Yes, some supplements contain both forms. Since the body can convert MK-7 to MK-4, some argue that MK-7 provides a steady, systemic level of vitamin K2, which the body can then use to create MK-4 in extra-hepatic tissues.