Hi parrotquee and lioness, happy to read you stopped strontium. Also that you researched it. I am using "LiveWell" grass fed, pasture raised Collagen Peptides. (no strintium) from Amazon. Had visit with oncologist, stopping anastrazole after 6 years. 3 months. Higher risk of fractures in arms from anastrazole which caused osteoporosis. Bone density showed I was high rush for fractures! Use a cane outside oh home, we must not fall. Had to get over being embarrassed to use a cane!.Seems like addition of Vit K2, and collagen is working. No pain and again feeling energized, and walking more.