This occurs when more of your bone tissue is being taken away from your bones (a process called resorption) than is being created (formation). Bone formation usually peaks at age 30; after that, resorption happens slightly more quickly than formation, but has few ill effects in most people. However, in some people this process happens much more quickly than normal, either because they are losing bone more quickly or because they cannot make new bone fast enough, causing osteoporosis.