Insulin is a hormone normally produced by the body. Its job is to help the body either use or store the glucose (sugar) it gets from food.
Diabetes occurs when the body either stops making insulin or can't properly use what it does make. When that happens, too much glucose stays in the blood. Insulin may be needed to get glucose back under control before it causes the damage that can accompany diabetes. 
For people with type&nbsp;1 diabetes&mdash;whose bodies produce none of this essential hormone&mdash;using insulin is a must. 
Some people with type&nbsp;2 diabetes&mdash;whose bodies don't use insulin properly&mdash;may be able to manage the condition without taking insulin. Others will need insulin to fully control their blood sugar levels. 
With both type 1 and type 2 diabetes, other medications may be needed in addition to insulin. 
The choices
There are more than 20&nbsp;types of insulin available in the United States, according to the <a target="_blank" href="http://www.netreturns.biz/healthinfo/bouncelink.aspx?shortcut=diabetes">American Diabetes Association</a> (ADA). They can differ in: 
<ul>
 <li>Onset&mdash;how quickly the insulin starts working. </li>
 <li>Peak time&mdash;when the insulin is at maximum strength in lowering blood sugar. </li>
 <li>Duration&mdash;the length of time the insulin keeps working. </li>
</ul>
It may take a combination of different insulin types to get blood sugar fully under control. 
Storing and using insulin
Insulin can be stored at room temperature if you will be using it within a month. If not, it should be stored in the refrigerator. Just remember to take it out of the fridge to warm up to room temperature before using it. 
The ADA offers these additional tips for storing and using insulin: 
<ul>
 <li>Keep insulin away from extreme heat and cold. </li>
 <li>Don't freeze insulin, leave it in direct sunlight or keep it in your car's glove compartment. </li>
 <li>Don't use insulin that's past its expiration date. Also, check for clumps in the insulin, discoloration, or crystals or frosting on the inside of the bottle. Don't use the insulin if any of these are present. </li>
</ul>
Delivery systems
Insulin must be injected, not taken as a pill, since it would be broken down in the digestive system. Injecting it allows it to get into the blood where it can do its work. 
But there are different ways to inject insulin. 
Needle and syringe. Most people who take insulin use this method. It's important to note that the area of the body where you inject makes a difference in how quickly insulin acts. Try to use the same area of the body (for instance, the abdomen), but vary the location so you're not injecting the exact same spot each time. Your doctor can recommend the best sites to inject. 
Insulin pen. These injection devices look like a pen with a cartridge. They can be disposable or refillable and are easy to use. Insulin pens use a very fine needle and may be less painful than standard needle and syringe injections. 
Insulin pump. The pump itself can be placed in a pocket or worn on your belt. The pump can deliver insulin day and night via a catheter inserted in the skin. 
Jet injector. This device uses high pressure to spray a fine mist of insulin through the skin&mdash;no needle required. 
Monitoring is key
Both the type of insulin you use and how it is delivered can affect how your blood sugar levels are controlled. Monitor your blood sugar levels as instructed by your doctor. And work closely with your doctor and healthcare team to find the combination that works for you.
Reviewed 10/2/2023

Insulin basics

Learn how to store and use insulin properly.