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Natto / Vitamin K2 (for Arteries) — Frequently Asked Questions

This content is for informational purposes only and does not constitute medical advice. Consult your healthcare provider before starting any supplement. Full disclaimer

Frequently Asked Questions

Can I take vitamin K2 if I am on blood thinners?

If you take warfarin or another vitamin K antagonist, do NOT take supplemental K2 without your doctor's explicit guidance. Vitamin K2 activates clotting factors that warfarin is designed to inhibit. However, some practitioners do use stable, low-dose K2 alongside warfarin with careful INR monitoring. If you take DOACs (like rivaroxaban or apixaban), K2 is generally safe since these drugs do not work through vitamin K pathways. Always consult your prescriber.

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

Both are forms of vitamin K2 but differ significantly. MK-7 (from natto) has a long half-life (~72 hours), allowing once-daily dosing and sustained blood levels. MK-4 has a very short half-life (~6 hours) and requires dosing 3 times daily. For arterial health, MK-7 is preferred because it maintains consistent activation of matrix Gla protein (the anti-calcification enzyme). MK-4 is primarily studied for bone health at high doses (45mg/day) in Japan.

Is nattokinase the same as vitamin K2?

No, they are completely different compounds that both happen to come from natto (fermented soybeans). Nattokinase is a fibrinolytic enzyme that helps break down fibrin in blood clots, supporting healthy blood flow. Vitamin K2 (MK-7) is a fat-soluble vitamin that activates proteins preventing arterial calcification. Many natto-derived supplements contain both, but they should be evaluated separately. Some nattokinase products are specifically processed to remove vitamin K2, making them safer for warfarin users.

Full Natto / Vitamin K2 (for Arteries) Guide

References

  1. (). Menaquinone-7 supplementation improves arterial stiffness in healthy postmenopausal women. A double-blind randomised clinical trial. Thrombosis and Haemostasis. DOI
  2. (). Dietary intake of menaquinone is associated with a reduced risk of coronary heart disease: the Rotterdam Study. Journal of Nutrition. DOI
  3. (). A single-dose of oral nattokinase potentiates thrombolysis and anti-coagulation profiles. Scientific Reports. DOI