Why taking the two vitamins together is important

While the combination of vitamin D3 and K2 shows great promise, experts caution that more is not always better. The same NIH review warns that taking high doses of vitamin D3 or calcium supplements without adequate vitamin K may have unintended consequences.
When vitamin D levels rise, your body absorbs more calcium. But if you’re deficient in vitamin K2, the nutrient that directs calcium into bones, that extra calcium can start depositing in soft tissues, such as arteries, kidneys, or joints. Over time, this buildup may contribute to arterial stiffness and cardiovascular disease (CVD), especially in people already at higher risk.