Arterial stiffness is a term to describe calcification and biological aging of the artery, oftentimes due to high blood pressure. It is more commonly knows as atherosclerosis, or thickening of the arteries. In a study of 244 postmenopausal women, 180 micrograms of menaquinone-7 (Vitamin K2) was administered on a daily basis. There were multiple tests of carotid and aortic artery health performed on the participants. There was a statistically significant improvement in arterial stifness associated with Vitamin K2, which was most pronounced in the women with the most arterial stiffness at the beginning of the study.