Is MK-7 (menaquinone-7) superior to MK-4 (menaquinone-4) in terms of absorption for vitamin K2 supplementation?

Vitamin K2 Absorption: MK-7 vs MK-4

MK-7 (menaquinone-7) is superior to MK-4 (menaquinone-4) in terms of absorption for vitamin K2 supplementation due to its significantly higher bioavailability and longer half-life. 1

Comparative Bioavailability of MK-7 vs MK-4

Absorption Differences

• MK-7 absorption:

  • Well absorbed with peak serum levels at approximately 6 hours after intake 1
  • Detectable in serum for up to 48 hours after a single dose 1
  • Accumulates to 7-8 fold higher levels during prolonged intake 2
  • Has a very long half-life resulting in much more stable serum levels 2

• MK-4 absorption:

  • Not detectable in serum at any time point after single dose administration 1
  • Even with consecutive daily administration, MK-4 supplementation does not increase serum MK-4 levels 1

Clinical Implications of Superior MK-7 Absorption

MK-7's superior bioavailability translates to greater clinical efficacy:

• Carboxylation of vitamin K-dependent proteins: MK-7 induces more complete carboxylation of osteocalcin compared to other vitamin K forms 2

• Extrahepatic activity: Among vitamin K homologs, only MK-7 can effectively promote γ-carboxylation of extrahepatic vitamin K-dependent proteins at nutritional doses around the recommended daily intake 3

• Bioactivity at lower doses: MK-7 can achieve clinical effects at lower doses due to its higher bioavailability and longer half-life than other vitamin K homologs 3

Physiological Impact of MK-7's Superior Absorption

The superior absorption of MK-7 has important implications for:

1. Bone health: MK-7 increases bone mineral density and promotes bone quality and strength through more effective carboxylation of osteocalcin 3

2. Cardiovascular health: MK-7 more effectively activates matrix Gla protein (MGP), which inhibits vascular calcification 4

3. Dosing frequency: Due to its longer half-life, MK-7 can be administered less frequently while maintaining stable blood levels 2

Important Clinical Considerations

Medication Interactions

When using vitamin K supplements, particularly MK-7, caution is needed with:

• Anticoagulant therapy: MK-7 supplements at doses as low as 10 μg can significantly influence anticoagulation sensitivity in some individuals taking vitamin K antagonists 5

• Warfarin interactions: Use of vitamin K antagonists for anticoagulation in patients undergoing dialysis is associated with up to 11-fold increased risk of developing calciphylaxis 6

Dosing Considerations

• For general supplementation, MK-7 is effective at lower doses than MK-4 due to its superior bioavailability
• For patients on anticoagulant therapy, even low doses of MK-7 (10 μg) can interfere with treatment 5

Conclusion

The evidence clearly demonstrates that MK-7 has superior absorption characteristics compared to MK-4, making it the preferred form of vitamin K2 supplementation when increased bioavailability is desired. MK-7's longer half-life and higher serum accumulation allow for more stable blood levels and more effective activation of vitamin K-dependent proteins throughout the body.