Insulin is a hormone made in the pancreas. It enables glucose to move from the bloodstream into the body’s cells, where it can be used for energy.
Insulin also allows glucose to be stored in the liver, for you to use later on when the blood glucose level decreases, such as overnight when you are not eating.
All people with type 1 diabetes will require insulin as the cells in the pancreas that usually produce insulin are destroyed by the immune system, so no insulin is produced. Some individuals with type 2 or gestational diabetes may also require insulin to help keep the blood glucose levels in a healthy range. For those with type 2 diabetes or gestational diabetes that do require insulin, it doesn’t mean that they have ‘failed’ in their diabetes management. In some people with type 2 diabetes the insulin being produced may not work properly, or the pancreas may not make enough insulin.
Gestational diabetes is a type of diabetes that can occur during pregnancy. Some of the hormones produced during pregnancy stop the insulin from working properly so the pancreas needs to make extra insulin but may not be able to make enough extra insulin to stop the blood glucose levels from going too high. One of the main goals of managing diabetes is keeping the blood glucose levels within the healthy ranges and you and your health care team can work out what suits you.
For some people, starting on insulin can be an overwhelming and a difficult time. Fear of needles and the worry of what others may think can sometimes be barriers, however current injection devices and small needle sizes can make injecting insulin more comfortable than most people imagine.
There are many different types of insulin and your GP or endocrinologist will determine what type of insulin and dose is right for you depending on your blood glucose levels and how your body responds to carbohydrates you eat. Some individuals may be on one injection a day and others may need four or more injections daily. It is impossible to know exactly how much any given individual requires so often your GP or specialist will start you on a low dose and increase it until it is just right for you. Over time, your insulin requirements may also change so it is important to monitor your blood glucose levels and discuss how to self-manage insulin titration with your GP, endocrinologist or diabetes educator.
Insulin delivery devices
Insulin is delivered into the subcutaneous tissue (just under the skin) by either injection (insulin pen or syringe) or via a delivery device such as an insulin pump. An insulin pump is a programmable electronic device that holds insulin in a reservoir and delivers insulin via an infusion set that has a small flexible cannula that is inserted just below the skin. Pump sets and cannulas need to be changed every 48 to 72hrs and require some input from the individual with diabetes as to their blood glucose levels and carbohydrates that they are eating. For more information about insulin pumps and the different types that are available, you might like to attend the Diabetes WA Type 1 Tech Night.
Other devices such as the iPort can be used for individuals who are on injections who have a fear of needles.
Syringes and needles are free for individuals registered with the NDSS as requiring insulin.
Where to inject insulin
Insulin is injected into the subcutaneous tissue under the skin. A shorter needle length (4-6mm) is generally the most appropriate as it is important to inject into the subcutaneous tissue and not into the muscle. The abdomen, flank, upper outer thigh and upper outer arms are all sites that can be used to inject insulin. It is important to inject into a slightly different spot within your chosen injection site each time to avoid fatty lumps (lipohypertrophy).
Factors that affect insulin absorption
Absorption of insulin is accelerated by:
- Injecting into an exercised area (eg thigh after a run)
- High temperatures (eg hot shower, bath, hot waterbottle, spa, sauna etc)
- Massaging the area around the injection site
- Injecting into muscle (which may happen if using needles longer than 6mm)
Absorption of insulin is delayed by:
- Scarring or lipohypertrophy (lumps due to repeatedly using the same injection site and/or reusing needles)
- Cold insulin
Variations in insulin absorption can cause fluctuations in blood glucose levels so it is important to try and minimise any factors that affect insulin absorption.
Important facts about insulin
- Store unopened insulin on their side in the fridge
- Do not allow your insulin to freeze
- Once opened, insulin may be kept at room temperature (less than 30 degrees) for up to 28 days
- Insulin can be safely carried in your handbag or pocket
- The stability of insulin can be impaired by extreme temperature. Avoid leaving your insulin in temperatures over 30 degrees such as the glove box of your car or in direct sunlight.
Do not use your insulin if:
- Clear insulin has turned cloudy
- The insulin has reached its used by date
- The insulin has been frozen or exposed to high temperatures
- Lumps or flakes are seen in the insulin
- The insulin has been open for longer than 28 days
- Used syringes, pens and lancets must be disposed of in an approved sharps container that is puncture proof and has a secure lid.
- Sharps containers can be purchased from your local pharmacy or through Diabetes WA
- Contact Diabetes WA or your local government for procedures of how to dispose of your sharps container.
For more information about insulin and managing insulin injections, you may like to attend the Diabetes WA ‘Living with Insulin’ workshop, which is suitable for people living with type 2 diabetes. More information is also available on the NDSS website.