Jarrow Formulas® MK-7 is naturally made via fermentation by Bacillus subtilis subsp. natto and is 10X better absorbed than K1 from spinach.* MK-7 is a longer-acting form of vitamin K vs. K1 and MK-4, and clinically proven to better support carboxylation of specific proteins needed to build bones and help protect arteries from calcium deposition.