Insulin injection. Diabetic woman injecting herself in the abdomen using a novopen. The novopen is a pen-like device which meters out the correct dose of insulin from portable cartridges. Insulin is a hormone made in the pancreas, which converts blood sugar to energy. Diabetes mellitus is a condition in which too little insulin is made. The consequence is that the body uses fats as an alternative to sugar. This causes ketone build-up which can lead to coma. The treatment for diabetes is a strict diet and regular doses of insulin.