Insulin is a hormone that helps cells use glucose (sugar) for energy. It works as a “key,” allowing the sugar to go from the blood and into the cell. In type 1 diabetes, the body doesn’t make insulin. In type 2 diabetes, the body doesn’t use insulin correctly, which can lead to the pancreas not being able to produce enough — or any, depending on the progression of the disease —insulin to meet your body’s needs.
Diabetes is normally managed with diet and exercise, with medications, including insulin, added as needed. If you have type 1 diabetes, insulin is required for life. This may seem difficult at first, but you can learn to successfully administer insulin with the support of your healthcare team, determination, and a little practice.
Insulin injection methods
There are different ways to take insulin, including syringes, insulin pens, insulin pumps, and jet injectors. Your doctor will help you decide which technique is best for you. Syringes remain a common method of insulin delivery. They’re the least expensive option, and most insurance companies cover them.
Syringes vary by the amount of insulin they hold and the size of the needle. They’re made of plastic and should be discarded after one use.
Traditionally, needles used in insulin therapy were 12.7 millimeters (mm) in length. Recent research shows that smaller 8 mm, 6 mm, and 4 mm needles are just as effective, regardless of body mass. This means insulin injection is less painful than it was in the past.
Where to inject insulin
Insulin is injected subcutaneously, which means into the fat layer under the skin. In this type of injection, a short needle is used to inject insulin into the fatty layer between the skin and the muscle.
Insulin should be injected into the fatty tissue just below your skin. If you inject the insulin deeper into your muscle, your body will absorb it too quickly, it might not last as long, and the injection is usually more painful. This can lead to low blood glucose levels.
People who take insulin daily should rotate their injection sites. This is important because using the same spot over time can cause lipodystrophy. In this condition, fat either breaks down or builds up under the skin, causing lumps or indentations that interfere with insulin absorption.
You can rotate to different areas of your abdomen, keeping injection sites about an inch apart. Or you can inject insulin into other parts of your body, including your thigh, arm, and buttocks.
The preferred site for insulin injection is your abdomen. Insulin is absorbed more quickly and predictably there, and this part of your body is also easy to reach. Select a site between the bottom of your ribs and your pubic area, steering clear of the 2-inch area surrounding your navel.
You’ll also want to avoid areas around scars, moles, or skin blemishes. These can interfere with the way your body absorbs insulin. Stay clear of broken blood vessels and varicose veins as well.
You can inject into the top and outer areas of your thigh, about 4 inches down from the top of your leg and 4 inches up from your knee.
Use the fatty area on the back of your arm, between your shoulder and elbow.
How to inject insulin
Before injecting insulin, be sure to check its quality. If it was refrigerated, allow your insulin to come to room temperature. If the insulin is cloudy, mix the contents by rolling the vial between your hands for a few seconds. Be careful not to shake the vial. Short-acting insulin that isn’t mixed with other insulin shouldn’t be cloudy. Don’t use insulin that is grainy, thickened, or discolored.
Follow these steps for safe and proper injection:
Gather the supplies:
- medication vial
- needles and syringes
- alcohol pads
- puncture-resistant sharps container for proper needle and syringe disposal
Wash your hands thoroughly with soap and warm water. Be sure to wash the backs of your hands, between your fingers, and under your fingernails. The Centers for Disease Control and Prevention (CDC) recommends lathering for 20 seconds, about the time it takes to sing the “Happy Birthday” song twice.
Hold the syringe upright (with the needle on top) and pull the plunger down until the tip of the plunger reaches the measurement equal to the dose you plan to inject.
Remove the caps from the insulin vial and needle. If you've used this vial before, wipe the stopper on top with an alcohol swab.
Push the needle into the stopper and push the plunger down so that the air in syringe goes into the bottle. The air replaces the amount of insulin you will withdraw.
Keeping the needle in the vial, turn the vial upside down. Pull the plunger down until the top of the black plunger reaches the correct dosage on the syringe.
If there are bubbles in the syringe, tap it gently so the bubbles rise to the top. Push the syringe to release the bubbles back into the vial. Pull the plunger down again until you reach the correct dose.
Set the insulin vial down and hold the syringe as you would a dart, with your finger off of the plunger.
Swab the injection site with an alcohol pad. Allow it to air dry for a few minutes before inserting the needle.
To avoid injecting into muscle, gently pinch a 1- to 2-inch portion of skin. Insert the needle at a 90-degree angle. Push the plunger all the way down and wait for 10 seconds. With smaller needles, the pinching process may not be needed.
Release the pinched skin immediately after you’ve pushed the plunger down and removed the needle. Don’t rub the injection site. You may notice minor bleeding after the injection. If so, apply light pressure to the area with gauze and cover it with a bandage if necessary.
Place the used needle and syringe in the puncture-resistant sharp’s container.
Follow these tips for more comfortable and effective injections:
- You can numb your skin with an ice cube for a couple of minutes before swabbing it with alcohol.
- When using an alcohol swab, wait for the alcohol to dry before injecting yourself. It may sting less.
- Avoid injecting in the roots of body hair.
- Ask your doctor for a chart to keep track of your injection sites.
Disposing of needles, syringes, and lancets
In the United States, people use more than 3 billion needles and syringes each year, according to the Environmental Protection Agency. These products are a risk to other people and should be disposed of properly. Regulations vary by location. Find out what your state requires by calling the Coalition for Safe Community Needle Disposal at 1-800-643-1643, or visiting their site at http://www.safeneedledisposal.org.
You aren’t alone in treating your diabetes. Before beginning insulin therapy, your doctor or health educator will show you the ropes. Remember, whether you’re injecting insulin for the first time, running into problems, or just have questions, turn to your healthcare team for advice and instruction.