Keep in mind that this product is not suitable for vegans. We offer all our vitamin k2 products with vitamin d3; This is because both have been shown to help maintain the bones. This is not the only reason why we have put these two vitamins together. The reason is that both work synergistically, which means that both help each other in terms of effectiveness. Vitamin D has several forms and can be confusing. There are two forms that are considered important for the health of primates and humans that are D2 and D3, ergocalciferol and colecalciferol respectively. Although the British and American pharmacopoeias considered them equivalent in the past, new studies have shown that vitamin D3 has a higher bio-efficiency and more stable in formulations, with a longer expiration date. That's why we chose cholecalciferol (D3) for all products that contain vitamin D. Vitamin D is a fat-soluble vitamin. Other fat-soluble vitamins are A, E and K and, being soluble in fat, they are stored in the body for a much longer period of time, and do not need to be consumed daily or in large quantities to maintain the correct levels . Therefore, it is easier to take too much fat-soluble vitamins. Vitamin K2 (menaquinone) is a type of vitamin K. This vitamin may contribute to normal blood clotting, so a lack of vitamin K could lead to unwanted bleeding. Another advantage of this vitamin is that it contributes to the maintenance of bones. Vitamin K can be found in many foods, for example: milk, spinach, cabbage and other green vegetables. Vitamin K is a fat-soluble vitamin, which means that it stays in the body for long periods of time.