Diabetes is a disease that occurs when your blood glucose, also called blood sugar, is too high. Glucose is your body’s main source of energy. Your body can make glucose, but glucose also comes from the food you eat. Insulin is a hormone made by the pancreas that helps glucose get into your cells to be used for energy.

If you have type 1 diabetes, you need insulin therapy to stay healthy. It replaces the insulin your body doesn’t make. If you have type 2 diabetes, insulin therapy might be part of your treatment. It’s needed when healthy-lifestyle changes and other diabetes treatments don’t control your blood sugar well enough.