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How do insulin injections and insulin pumps deliver insulin to people with diabetes mellitus?

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An anatomical illustration of the human pancreas shows its location near the stomach and intestines, a detailed cross-section highlighting ducts and the islet of Langerhans, and an inset of pancreatic tissue histology with labeled alpha, beta, and delta cells. — diabetes mellitus The islets of Langerhans are responsible for the endocrine function of the pancreas. Each islet contains beta, alpha, delta, and pancreatic polypeptide (PP) cells that are responsible for the secretion of pancreatic hormones. Beta cells secrete insulin, a well-characterized hormone that plays an important role in regulating glucose metabolism.

Because insulin is a polypeptide that would be destroyed by digestive enzymes in the stomach, it cannot be taken orally and must be administered parenterally to enter the bloodstream.1

Insulin Injections: These are typically administered subcutaneously (under the skin). Patients often use a regimen that combines different types of insulin—such as rapid-acting insulin to cover meals and long-acting insulin to provide a constant, basal level of the hormone—to mimic the body's natural secretion patterns.12
Insulin Pumps: These devices provide an alternative to multiple daily injections. An insulin pump allows patients to control variations in the rate of insulin administration, offering greater flexibility in managing basal levels and mealtime pulses of the hormone.2

By utilizing these methods, patients can better manage diabetes mellitus and maintain glucose homeostasis, which is essential for preventing the complications associated with hyperglycemia.21