The calcium complex in New Chapter Bone Strength Take Care is derived from a special form of plant called Algas Calcareas (AlgaeCal) that is harvested from the pristine shores of a protected national reserve park in South America. Because calcium alone isn't enough, Bone Strength Take Care also provides key whole-food complexed nutrients like Vitamin D3, which helps in the absorption of calcium, and Vitamin K, which helps in the maintenance of bones.