Insulin is a hormone made by your beta cells in the pancreas. Its main job is to help move glucose from your bloodstream into your cells so you can use it for energy. Glucose needs to attach to insulin in order to get into the cell. Without insulin, glucose stays in the bloodstream instead of moving into the cell where it’s needed. (Exercise is the exception — contracting muscles can take up glucose without insulin.)
When insulin works well, blood sugar stays steady and your cells get the fuel they need. But when your body becomes resistant to insulin, your pancreas has to make more and more of it to get the same job done. Over time, this can exhaust your beta cells and raise blood sugar.
For a closer look at the cells that make insulin, see the glossary entry on beta cells.
Take a 10‑minute walk after your next meal. Even a short walk helps your muscles use glucose without needing as much insulin.