as a follow up to my last post, I thought I would post this paper summarizing some studies on the use of eggshell powder.
https://pubmed.ncbi.nlm.nih.gov/15018022/

The significant takeaways:
"Clinical studies in postmenopausal women and women with senile osteoporosis showed that eggshell powder reduces pain and osteoresorption and increases mobility and bone density or arrests its loss. The bioavailability of calcium from this source, as tested in piglets, was similar or better than that of food grade purified calcium carbonate. Clinical and experimental studies showed that eggshell powder has positive effects on bone and cartilage and that it is suitable in the prevention and treatment of osteoporosis."

So, almost seems to good to be true, especially that last line. But with all that said, seems like a good option to include in our regimens with the hopes that it can have some positive effect.