Human bones start losing density at a rate of about 1% every year once a person reaches age 30.

Bone is living tissue that undergoes a process called remodeling. Two types of cells handle this work. Osteoblasts build new bone tissue. Osteoclasts break down and remove old bone tissue.During childhood and your 20s, your body builds bone faster than it removes it. Most people reach their peak bone mass between ages 25 and 30. After this point, the osteoblast cells slow down while the osteoclasts keep working at the same speed.This imbalance leads to a steady loss of bone minerals. For women, this loss happens faster during menopause because estrogen levels drop. Estrogen is a hormone that helps keep bones strong. Women can lose up to 20% of their bone mass in the five to seven years after menopause starts.The National Institutes of Health recommends calcium and Vitamin D to help slow this process. Weight-bearing exercises like walking or lifting weights also help. These activities create stress on the skeleton. This stress signals the body to produce more bone tissue through a rule called Wolff's Law.