Insulin is an important hormone produced by the body in the pancreas. It is a protein which means it is made up of base units called amino acids. The image below is the three-dimensional structural form of the molecule insulin.
Insulin allows cells to uptake glucose from the bloodstream by binding to a receptor on the cell membrane. In this case, the orange molecule represents insulin and the blue molecule represents the cell’s receptor which is attached to the plasma membrane.
A simplified diagram shown below represents insulin allowing glucose to enter the cell.
Since insulin is a protein, it has to be stored carefully, otherwise it becomes inactive (denatured). This means that insulin must be stored in the refrigerator when not being used or at room temperature when being used. It will not function properly if subjected to extremes of temperature.
There are also different types of insulin that are used. These vary on what is called their profile of action (i.e. how long it takes for the insulin to act, when does the effect of the insulin peak and how long does it last). These factors are determined by how readily the insulin is broken down into single molecules, how quickly it absorbed from under the skin and how well it binds to insulin receptors. The list below contains some of the different insulin types and their common brand names (N.B. this list is not exhaustive):
Your insulin will be chosen by your medical professional but it is important to understand the different profiles and dosing requirements.
In order for patients living with Type 1 diabetes to have adequate blood sugar control, insulin has to be injected into fatty tissue (subcutaneously) where it is then absorbed into the blood stream. There are numerous different insulin types, patterns of injection and methods of insulin injection (e.g. insulin pens and insulin pumps).
In a perfect world, insulin therapy would exactly copy the secretion of insulin by the pancreas. The graph below shows that there are two factors which need to be considered when dosing insulin. A basal injection (usually long-acting insulin) mimics the background levels of insulin which are always present in the body and a bolus injection (usually a rapid-acting insulin) mimics the peaks in insulin levels during mealtimes.
This page will focus on insulin pens but if you are using an insulin pump, please proceed to the next page.
There are different patterns of insulin dosing dependent on what your healthcare professional recommends. The most common routine is the basal-bolus injection plan (also know as multiple daily injections). This consists usually of 3 bolus injections of rapid-acting insulin at breakfast, lunch and dinner as well as once or twice daily a basal injection of long-acting insulin. There are various ways of applying this routine which include
The following is a set of general guidelines in order to use insulin pens correctly and safely:
When newly diagnosed, the injection of artificial insulin allows the pancreas to recover and insulin requirements may decrease. This is because the pancreas is still producing some of the required insulin. The time that the honeymoon lasts for is variable but research is underway to see whether tight blood sugar control and other factors may extend this period.