At what angle should the needle be inserted for an insulin injection?

For an insulin injection, the preferred angle of needle insertion is typically between 45 and 90 degrees. This range is important because it ensures that the insulin is delivered into the subcutaneous tissue, where it can be absorbed effectively. Injecting at a 90-degree angle is particularly suitable for individuals with more considerable subcutaneous fat, ensuring that the needle penetrates deep enough to reach the insulin application site without reaching the muscle layer. This depth enhances the insulin's efficacy by providing consistent absorption rates.

In contrast, lower angles, such as 15 to 30 degrees, might not penetrate the subcutaneous tissue effectively, potentially leading to inadequate insulin absorption. Angles beyond 90 degrees may be impractical or even harmful, as they could risk intramuscular injection, which can alter the pharmacokinetics of the insulin, leading to unpredictable blood glucose levels. Thus, the 45 to 90-degree range is a clinically accepted practice for achieving optimal results during insulin administration.