Myostatin
What it means
Myostatin is a molecule made by muscle that slows down growth in both muscle and bone tissue.
Understanding myostatin helps explain why muscle and bone loss so often happen together as you age.
Myostatin is a signaling molecule made by your muscles. Its main job is to put the brakes on tissue growth — it suppresses both muscle building and bone building at the same time. Think of it as a 'slow down' signal that keeps muscle and bone from growing without limit.
This matters because muscle and bone are constantly talking to each other, not just pulling on each other during exercise. Working muscle also releases helpful messengers called myokines, like irisin, which encourage bone-building cells to get to work. Myostatin works in the opposite direction, holding back growth in both tissues at once.
This chemical conversation helps explain why age-related muscle loss (sarcopenia) and bone loss (osteoporosis) tend to show up together so often that researchers now think of them as two sides of the same condition, rather than separate problems.
How sure is this?
Graded Emerging Evidence: Promising research, but findings are still developing and may be primarily from laboratory or animal studies. Read each study with its grade in mind. One study is a piece of the picture, not the whole of it.
Where the Academy teaches it
This page is the short version. The lessons teach it in full, with the context around it and a quiz to lock it in.
Related words
Myokines are chemical messengers released by working muscle that can signal bone cells, linking muscle activity and…
Irisin is a chemical messenger (myokine) released by working muscles that signals bone-building cells to become active.
Osteocalcin is a hormone made by bone that helps regulate blood sugar, muscle energy use, and other body functions…
Sarcopenia is the gradual loss of muscle mass and strength that comes with aging, and it's closely tied to bone health.
Osteoporosis is a condition where bone breakdown outpaces bone building, causing bones to become thinner, more…
Lean mass is mostly your muscle weight — the non-fat part of your body. It's tracked because it's closely linked to…
Education only, not medical advice. Decisions about tests, medications and treatment belong with your own doctor. OsteoStrong does not diagnose, treat or cure any disease.
