Insulin Injection Technique and Site Rotation

Insulin is intended to form a small depot in subcutaneous tissue, where it is absorbed at a reasonably predictable rate. If insulin reaches muscle instead, it is absorbed faster and less predictably. The patient may then experience an unexpectedly rapid glucose decline and hypoglycemia. For human insulins, absorption is generally fastest from the abdomen, followed by the arms, thighs, and buttocks. Rapid-acting and long-acting analogues are less dependent on region, but consistency still matters. Using the same anatomical region for a particular time of day reduces avoidable day-to-day variation in insulin action. For example, a person who usually injects their breakfast dose in the abdomen should not switch unpredictably between abdomen, thigh, and arm simply because each site is available. They should rotate within the planned region. Injection technique remains relevant for people using pens or vials and syringes, even though pumps and automated insulin delivery are increasingly used. Whenever prescribed insulin is injected, the tissue, site, needle, and sequence affect the dose that actually reaches circulation. [1, 4]