Insulin is a hormone produced by the pancreas that helps move glucose (blood sugar) from the bloodstream into the cells of the body. The cells break down glucose and convert it to energy. When the body cannot produce insulin or fails to respond properly to it, glucose builds up in the blood. This condition is known as diabetes.

Patients with type 1 diabetes produce virtually no insulin and depend on insulin therapy to survive. In patients with type 2 diabetes, either their cells are resistant to insulin or the body does not use it effectively. This allows sugar to build up in the bloodstream, which triggers complications of diabetes. When exercise, diet and antidiabetic agents are not sufficient to manage type 2, insulin treatment may be necessary to maintain normal glucose levels.

Insulin treatments help prevent glucose levels from going too low or too high. Untreated, diabetes can cause long-term health problems, such as serious nerve, blood vessel, kidney and eye problems.

Women with gestational diabetes, which can develop during pregnancy, also may need insulin injections because they generally cannot take antidiabetic agents.

A physician will examine a patient’s diet, exercise habits, physical condition and stability of glucose levels to determine the appropriate insulin therapy. Though patients can obtain most forms of insulin without a prescription, a physician should always be consulted when developing a dosage level and treatment regimen.

Syringe injections are the most common way of taking insulin. Other methods include insulin pumps, insulin pens, insulin jet injectors and inhaled insulin.