Sclerostin suppression by loading

When bones are loaded through everyday movement or exercise, they bend very slightly. Osteocytes, the long-lived cells buried inside bone, sense this bending through tiny fluid movements around them. In response, they make less sclerostin, a protein that normally acts like a brake on bone formation. With less of the brake on, bone-building cells called osteoblasts become more active.

This system is part of what scientists call the mechanostat, the body's way of matching bone strength to the forces placed on it. Less sclerostin allows more signaling through the Wnt/beta-catenin pathway, which helps turn on osteoblast activity. It's one reason weight-bearing and resistance exercise are considered useful habits for bone health alongside good nutrition and medical care.

This is also how a newer osteoporosis medication, romosozumab, works: it directly blocks sclerostin to encourage bone formation. That drug is prescribed and monitored by a doctor, who weighs benefits and risks for each person. Exercise can't replicate a drug's effect, but understanding this pathway helps explain why staying physically active is generally encouraged for bone health, alongside whatever treatment plan your doctor recommends.