What is insulin?

Insulin is vital for life. It is a hormone produced by a part of the pancreas called the islets of Langerhans, and it is the key in helping glucose in the bloodstream to enter the body's cells where it is used as fuel to power the body. In this way, insulin regulates blood glucose levels, preventing them from becoming too high or too low. In people with diabetes, either insulin is entirely absent, or levels are reduced or it doesn't work properly. Either way, blood glucose levels are left to rise unchecked.