@geranium1 So far I'm doing well with calcium hydroxyapatite. It's a combination of calcium and phosphorus. I'm currently taking the NOW brand. I can't remember now why I chose that combination, but I do remember reading about the advantages at the time. Both my blood and urine calcium levels have been within range. I'm only taking 1 capsule 2x a day as apparently my calcium intake from food is making up for the rest. I eat very little dairy, so this is encouraging!