Vitamin C contributes to normal collagen formation for the normal function of bones, cartilage, skin and teeth. Calcium and magnesium are needed for the normal maintenance of bones and teeth. Vitamin D contributes to normal blood calcium levels and to the normal absorption / utilisation of calcium. Vitamin D also helps maintain normal bones, teeth and muscle function. Vitamin K contributes to the maintenance of normal bones. The vitamin C in this formula is buffered to be gentle on the stomach. The calcium and magnesium are chelated as citrates. Additional boron and malic acid. Vitamin D in this formula is vegan.