I have been using this supplement for at least a couple of decades because of severe osteoporosis. The bone density test still says I have severe osteoporosis, but the specialists claim it would be even worse without this supplement. Given other research on the correlation between CA supplements and risk to the heart, and my own healthy diet, I take only 6 tabs a day instead of the recommended 8. I also focus on bone-strengthening exercise even at age 78. I am pleased to have another source for PL's product other than PL (which used to sell it directly) and Amazon.com, which now has too much power over our lives.