Jarrow Formulas® MK-7 is crafted through a natural fermentation process by Bacillus subtilis subsp. natto, offering up to 10X more absorption of vit. K than K1 from spinach.* This form of K is longer lasting compared to MK-4 and K1, and has been clinically proven to support the body in producing the proteins necessary for strong bones, as well as guarding against calcium blockages in the arteries.*