What is insulin?

Insulin is a hormone that is made in a working pancreas, a gland located in the abdomen. Insulin ensures the food that you eat is able to enter your body’s cells to provide nourishment. When insulin is working as it should it will keep your blood sugar at a safe, healthy range and prevent your blood sugar from going too high.

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If my body makes insulin, why do I have to inject it?

For people with type 1 diabetes, the pancreas does not work to make insulin so insulin has to be taken as a medication.

For people with type 2 diabetes, the pancreas may still make insulin, but it isn’t working properly. Sometimes people with type 2 diabetes have to inject insulin to help keep their blood sugar at a healthy range.

How is insulin taken?

Insulin is prescribed by your provider in either an injectable or inhalable form. There are different types of insulin and amounts are individualized and can change.  Insulin can be delivered in a plastic pen with a pen needle, glass vial with a syringe, or as an inhalable powder. Your diabetes care team will work with you to decide what the right type, dose, and timing is for you.

Injecting Insulin with a Pen Needle

Injecting Insulin with a Syringe

What are the different types of insulin?

Bolus insulins (work quickly to help you at mealtime)

Since the bolus insulins work so quickly in the body, it’s most important for you to take these medications BEFORE you start eating. Getting in the habit of injecting before a meal (either 10-15 minutes prior for rapid-acting, or 30 minutes prior for short-acting),  will help your body use the insulin with your meals and prevent your blood sugar from going too high or too low after a meal.

Basal insulins (work throughout the day to keep blood sugar stable between meals)

Basal insulins work like a dripping faucet throughout the day and night. They constantly and slowly break down under the skin to deliver small doses of insulin to keep your blood sugar steady while you sleep and between meals.


These insulins that are a combination of the fast-acting and the slow-acting insulins in the same vial or pen.

How do I store my insulin?

If you fill a prescription with more than one vial or pen of insulin, store the insulin that is not in use in the refrigerator. Do not store insulin in the freezer. The vial or pen that’s in use can be stored at room temperature. Once the seal is broken, the insulin can be used for about 28 days. Please do not store your insulin in the car or freezer. Wide changes in temperature, or if the insulin becomes too cold or too hot, it will become damaged and will no longer work as expected, and a new pen or vial should be started. Ideally, do not prefill syringes however if this is necessary please discuss with your health care team.

Where do I inject my insulin?

Insulin needs to be injected into fatty tissue directly under the skin, not the muscle. Recommended sites include the abdomen, outer thigh, buttock, and the back of the upper arm. Choose from these areas and inject in a consistent rotation (see insulin animation). It’s important to not “overuse” any particular area of the skin. If you develop hard lumps under your skin where you are injecting, you should move to a different area. If you experience any changes in your skin, contact your doctor.

Where do I put my needles after I use them?

Much like your lancing devices, syringes and pen needles are a one-time use product and should not be reused. Do not leave pen needles on your insulin pen. This can cause your insulin to leak or for air to enter the cartridge. Do not share any of your lancing needles, pen needles, or syringes. When you are done with an injection, immediately put any used sharps into one of the following:

  1. FDA-approved “sharps” container.  These can be purchased online, at drug stores, or at office supply stores
  2. Make your own sharps container using an empty laundry detergent container.
    1. Write “Sharps. Biohazard. Do Not Recycle” on it. When it is 2/3 full, screw the lid on tightly and tape with duct tape. Don’t use glass bottles, plastic water bottles, milk jugs or cartons, or soda cans

Once the container is full, it’s important that you know what to do with it. Each state has different rules. Some allow trash or recycle disposal, others require you to bring it to a needle disposal site.