Let's first talk about the defintion of insulin. Insulin is a protein that comes from an organ called the pancreas which is located in the mid-abdomen.The term Insulin, which is also  known as insula in Latin and island in English, has become popular and most-talked about now because of the rampant and threatening disease known as diabetes. It is a regulating polypeptide hormone that controls the life sustaining chemical activity of carbohydrate. It is a primary stimulus in carbohydrate homeostasis and takes part in the metabolism of fat and foods rich in proteins.

Furthermore, insulin is used medically for some forms of diabetes mellitus. Type 1 diabetic patients of  mellitus depend on exogenous insulin for their continued existence because of an absolute shortage of the hormone. Type 2 diabetes mellitus patients have either relatively low insulin production or struggle in insulin and so they occasionally require insulin administration if other medications are insufficient in controlling blood glucose levels. 

So what does insulin do exactly  and what is its role in the smooth functioning of your body?

Firstly, insulin encourages your body’s cells to drain glucose from your blood and store it as glycogen in the liver and muscles of your body. It is used as an energy source for your body as and when required and stops the body from burning fat to create energy. If insulin levels become low or insulin is non-existent the body will start to use fat as an energy source which can then force itself upon other areas and other functions of the body as well as inciting the condition of diabetes. In short, that is what insulin does in our body.

There are only two major types of insulin, even though there are many different ones available in the market. There is the background insulin which imitates the pancreas' slow secretion of insulin throughout the day and night. Another is a meal-time insulin, which is also called prandial insulin, that the patients can also inject. Hence, insulin seems to be very complicated perhaps, but in reality it is quite simple as all we are trying to do with modern-day insulin therapy is mimic what a normal pancreas does.

How Does Insulin Work
Even though insulin from a pig is also known to be the closest match to the human variant, the difference across the species is very small though in some circumstances, insulin from fish has been known to give a medical shock for diabetic patients. Unlike many other hormones and fundamentals of the body, the insulin that we know today has changed very little over the centuries, which many scientists believe, echoes its importance to the animal and human kingdom in relation to the metabolic control system.

Insulin is vital to the overall efficiency of the human and animal body and without it, serious side effects occur. The ability to balance the metabolism of the body is vital and research into why some people produce less insulin and why some produce none continues even today . Researchers have made much progress with regards to the production of synthetic insulin although a cure for type 1 and 2 diabetes appears to be some way off. So, I think that more or less answers the question - what does insulin do in our body.