Insulin Absorption Rate Fluctuation Depending on Injection Site

There are many types of insulin, and they all act differently in the body according to their respective chemical structures. But did you know that the same type of insulin can have varying absorption rates depending on the injection site

There are four approved sites for the subcutaneous injection of insulin: 

  • Abdomen: You can do an injection anywhere outside a two-centimetre (or two-finger) radius around the navel.
  • Thighs: It is recommended to use the outside of the thighs and to keep at least a one-hand distance from the knee or hip.
  • Upper buttocks
  • Back of the arms: If you have a hard time reaching the back of your arm, try leaning your arm on the back of a chair and pivoting slightly.

How does the insulin absorption rate fluctuate?

Remember that no matter what injection site you use out of these four, the quantity of insulin that is absorbed remains the same. The absorption rate is the only aspect that can vary from one site to the other. This is important to know when choosing an injection site for certain types of rapid-acting insulin taken at mealtime. The abdomen is generally the subcutaneous injection site with the fastest absorption rate. The arms have an average absorption rate, while the buttocks and thighs have a slower absorption rate.    

Absorption rate fluctuations vary from one person to the other, and depending on the type of insulin. They seem to be more frequent with rapid-acting types of insulin and minor with the latest types.

Insulin absorption rate is known to be a lot quicker when the insulin is injected in a muscle than when injected in fat tissue. It is important that you use the right type and length of needle for your build.

Also, remember that any of the following can increase the insulin absorption rate:

  • A massage over the injection site
  • A hot bath
  • Physical activity that solicits the body part used for the injection

Things to consider for your next injection

You can use this information when you decide where to inject insulin next. For example, if your blood sugar always rises quickly after breakfast, you could do the injection in your abdomen and see whether this improves your blood sugar. Or if your blood sugar doesn’t rise quickly enough after supper, you could try an injection in your upper buttocks.

Beware! A higher insulin absorption rate also means a greater risk of hypoglycemia. So, you need to remain vigilant and take this factor into consideration when choosing your injection site. For example, if you’re planning to play tennis after a meal, avoid injecting your insulin into your arms.

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  • Gradel, A. K., Porsgaard, T., Lykkesfeldt, J., Seested, T., Gram-Nielsen, S., Kristensen, N. R., & Refsgaard, H. H. (2018). Factors Affecting the Absorption of Subcutaneously Administered Insulin: Effect on Variability. Journal of Diabetes Research, 1-17. doi:10.1155/2018/1205121

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