Source Naturals Vitamin K, also known as phylloquinone, is a fat-soluble vitamin known for its role in the biological activity of multiple blood coagulation factors. Vitamin K may also play a role in blood health, as well as in the synthesis of the bone proteins osteocalcin and matrix Gla-protein, which are involved in calcium and bone metabolism. Contains no yeast, dairy, egg, soy, starch, salt, preservatives, or artificial color, flavor or fragrance.