Insulin is a hormone produced in our body by pancreas. Its function is to take glucose from blood and transport it to different parts of the body thereby reducing the level of glucose in blood. In diabetes pancreas does not produce enough insulin, glucose keeps on getting accumulated in blood, thereby raising blood glucose levels. Insulin is used as a medication to treat high blood sugar. This includes in diabetes mellitus type 1, diabetes mellitus type 2, gestational diabetes, and complications of diabetes such as diabetic ketoacidosis and hyperosmolar hyperglycemic states In general.
So if pancreas secretes little or no insulin, or your body becomes resistant to insulin's action, the level of glucose in your bloodstream increases because it's unable to enter cells. Left untreated, high blood glucose can lead to complications such as blindness, nerve damage and kidney damage and thus require insulin from outside. Insulin therapy helps to prevent the onset of complications in people with diabetes by keeping blood sugar level under control. There are different varieties of insulin available in the market. Your Doctor will recommend your insulin type requirement after considering several factors like your type of diabetes, your blood sugar range, and your lifestyle etc. Insulin must be injected or given via an insulin pump. It cannot be given orally because it is a protein and is broken down in the stomach before it can be absorbed. Insulin is injected underneath your skin, once or more than once in a day as per the blood sugar requirements.