Our bones are living tissue and constantly changing. From the moment of birth until young adulthood, bones are developing and strengthening. Our bones are at their most dense in our early 20s – called peak bone mass. As we age some of our bone cells begin to dissolve bone matrix (resorption), while new bone cells deposit osteoid (formation). This process is known as remodeling.For people with osteoporosis, bone loss outpaces the growth of new bone. Bones become porous, brittle and prone to fracture.