Treatment of diabetes with insulin

Insulin is the mainstay of treatment for patients with type 1 diabetes. Insulin is also important in type 2 diabetes when blood glucose levels cannot be controlled by diet, weight loss, exercise, and oral medications.
Ideally, insulin should be administered in a manner that mimics the natural pattern of insulin secretion by a healthy pancreas; however, the complex pattern of insulin secretion by the pancreas is difficult to duplicate. Still, adequate blood glucose control can be achieved with careful attention to diet, regular exercise, home blood glucose monitoring, and multiple insulin injections throughout the day. For more, please see the Diabetes and Home Care Monitoring article.
In the past, the insulin was being derived from animal sources, particularly cows and pigs. Not only was there a problem with enough supply of insulin to meet the demand, but beef and pork insulin also had specific problems. Originating from animals, these types of insulin caused immune reactions in some people. Patients would become intolerant or resistant to animal insulin. With the acceleration of scientific research in the latter half of the twentieth century, beef and pork insulin were replaced by human insulin. In 1977, the gene for human insulin was cloned, and through modern technology, manufactured human insulin was made available. Human insulin is now widely used.
Insulin now comes in a variety of preparations that differ in the amount of time following injection until they begin to work and the duration of their action. Because of these differences, combinations of insulin are often used to allow for a more tailored regimen of blood sugar control. The table below lists the most common types of insulin currently in use in the U.S. and their specific properties.