Overview Insulin Pen What is an insulin pen?

An insulin pen looks like a writing pen. But it has a single-use needle for its point and insulin as its “ink.” There are several types of insulin pens.

Parts of an insulin pen

While there are several types of insulin pens, they all have similar basic parts, including:

• Insulin reservoir: This is a clear plastic container that holds the insulin in the pen. You can see the “quality” of the insulin (like if it’s cloudy or clear) and how much insulin is left in the pen. Some pens have insulin cartridges (reservoirs) that you can replace. Other pens are disposable — you throw them away once the insulin reservoir runs out.
• Pen cap: The cap protects the insulin reservoir from damage when you’re not using the pen.
• Rubber seal: The rubber seal is where you connect a single-use needle for an injection.
• Needle: Needles for insulin pens are single-use, which means you only use them for one injection and then throw them away. Each needle comes in a sterile protective container. You remove the needle from the container and attach it to the pen before an injection. Pen needles come in different sizes. Talk to your healthcare provider to choose the pen needle that’s best for you.
• Dosage knob: This is a knob you turn to select the insulin dose you need.
• Dosage window: This shows the number of units of insulin you select using the knob.
• Injection button: Once you inject the pen needle, you press the injection button to give the insulin dose.
• Label: The label tells you the type and brand of insulin in the pen and its expiration date.