Jarrow Formulas K-Right is a combination of three forms of Vitamin K: MK-7, MK-4 and K1, plus vitamin D3 to support bone and cardiovascular health. Vitamin K functions in the carboxylation of osteocalcin, which binds calcium in bones. Vitamin D3 functions in the production of osteocalcin. Jarrow Formulas MK-7 is a product of natural fermentation using Bacillus subtilis subsp. natto.