What is diabetes? Diabetes is a condition that happens when your blood sugar (glucose) is too high. It develops when your pancreas doesn’t make enough insulin or any at all, or when your body isn’t responding to the effects of insulin properly. Diabetes affects people of all ages. Most forms of diabetes are chronic (lifelong), and all forms are manageable with medications and/or lifestyle changes. Glucose (sugar) mainly comes from carbohydrates in your food and drinks. It’s your body’s go-to source of energy. Your blood carries glucose to all your body’s cells to use for energy. When glucose is in your bloodstream, it needs help — a “key” — to reach its final destination. This key is insulin (a hormone). If your pancreas isn’t making enough insulin or your body isn’t using it properly, glucose builds up in your bloodstream, causing high blood sugar (hyperglycemia). Over time, having consistently high blood glucose can cause health problems, such as heart disease, nerve damage and eye issues. The technical name for diabetes is diabetes mellitus. Another condition shares the term “diabetes” — diabetes insipidus — but they’re distinct. They share the name “diabetes” because they both cause increased thirst and frequent urination. Diabetes insipidus is much rarer than diabetes mellitus.