If you inject insulin three or more times a day then it’s a good idea to rotate your injection sites. Injecting in the same place much of the time can cause hard lumps or extra fat deposits to develop. These lumps are not only unsightly; they can also change the way insulin is absorbed, making it more difficult to keep your blood glucose on target.
Follow these two rules for proper site rotation:
Injection site rotation is important for both insulin syringe and pen users.
Same Time, Same General Location
Insulin is absorbed at different speeds depending on where you inject, so it's best to consistently use the same part of the body for each of your daily injections. For example, do not inject your lunch bolus dose in the abdomen on Monday and in the thigh on Tuesday. If you have picked the thigh for your evening injection, then continue to use the thigh for all of your evening injections.
According to Eli Lilly, the leading manufacturer of insulin, most insulin enters the blood:
Fastest from the abdomen (stomach)
A little slower from the arms
Even slower from the legs
Slowest from the buttocks
Unless your doctor has told you otherwise, it is a good idea to inject your breakfast and lunch bolus doses into the abdomen. Insulin is absorbed fastest when injected into this area. Fast absorption is needed at mealtimes to cover the carbohydrates you are about to eat.
On the other hand, your supper or bedtime dose of long-acting insulin could be injected into the thigh, buttocks, or upper arm. That's because you want the long-acting insulin to take effect gradually and cover your needs throughout the night.
If you mix two types of insulin in one shot, you can inject into the abdomen, arm, thigh, or buttocks.
Rotate Within an Injection Site
To avoid developing hard lumps and fat deposits, it is important to inject in different spots within a general part of the body.
Smart Tips for Site Rotation
Work with your doctor and track your blood glucose levels carefully when you begin practicing site rotation. Over time, you and your doctor will learn which injection sites give you the best blood glucose control at different times of day.