More About Insulin

Insulin is injected, not swallowed, because it is destroyed by acid in the stomach. New forms, such as an insulin nasal spray and a form that can be taken by mouth, are being tested. Insulin is injected under the skin into the fat layer, usually in the arm, thigh, or abdominal wall. Insulin is absorbed fastest from the abdominal wall and slowest from the thigh. A person should use one of these three sites consistently and rotate injections within the site (for example, different areas of the abdominal wall) to avoid complications, such as an allergic reaction, fat deposits, or indentation of the skin.

An air pump device that blows the insulin under the skin can be used for people who cannot tolerate needles, but most people find them more problematic than the tiny needles available today. An insulin pen, which contains a cartridge that holds insulin, is a convenient way for many older people to carry insulin, especially if they cannot see well enough to draw insulin into the syringe.

Insulin preparations generally are stable at room temperature for up to several months, allowing them to be taken outside the home. Insulin should not, however, be exposed to extreme temperatures.