Insulin is a hormone that is crucial for regulating blood sugar levels in the body. It is produced by the pancreas and helps cells absorb glucose (sugar) from the bloodstream to use as energy or store for future use. Insulin plays a vital role in managing the energy and glucose metabolism in the body.

People with diabetes, either type 1 or type 2, often have issues with insulin production or function. In type 1 diabetes, the body's immune system attacks and destroys the cells in the pancreas that produce insulin. In type 2 diabetes, the body either doesn't produce enough insulin or the cells ignore the insulin. Managing blood sugar levels with insulin injections or other medications is crucial for people with diabetes to prevent complications such as heart disease, kidney damage, and vision problems.

Insulin therapy is commonly used for managing diabetes, where synthetic or animal-derived insulin is administered to the patient. There are various types of insulin based on how quickly they start to work and how long their effects last, including rapid-acting, short-acting, intermediate-acting, and long-acting insulins. The type and dosage of insulin are determined based on the individual's specific needs and blood sugar levels.