Supplement · Vitamins
Vitamin K (K1 & K2)
Also known as: Phylloquinone, Menaquinone, MK-7
Essential for clotting (K1) with emerging bone and arterial claims for K2.
- Evidence
- Silver· human data
- Sources cited
- 1
- Last reviewed
- 22 July 2026
Vitamin K1 (from leafy greens) is essential for blood clotting, an established and non-negotiable role. Vitamin K2 (menaquinones such as MK-7) helps direct calcium into bone and away from arteries.
The K2 bone and cardiovascular-health claims are biologically plausible and supported by early human data, but remain preliminary rather than proven. An important caution: vitamin K interacts with the anticoagulant warfarin, so anyone on it should keep intake consistent and take medical advice.