An insulin pen is a convenient and discreet method for diabetes patients to take prescribed insulin medication. These devices resemble a fountain pen and are disposable or have replaceable insulin cartridges. A short, thin needle at the end of the pen is used to inject the insulin. A small dial allows the individual to select the exact dosage needed.

Pens are typically the size of a large marker and carry 150 or 300 units of insulin. They may be a good option for diabetes patients who are traveling, and can be used and stored easily at work or school. Their convenience and ease of use also may make them good options for certain populations, such as children and elders.

It is important that patients using insulin pens ensure that they properly mix the insulin before injecting the drug. Research indicates that many patients are not properly mixing their dosages, which results in insulin that is absorbed too quickly. This increases the risk of hypoglycemia.