Insulin therapy helps control blood sugar levels in diabetes. What type of insulin you take, how often you take it, and how it’s administered are all part of your individualized treatment plan.

Diabetes is a chronic medical condition. It occurs when your body can’t effectively use the hormone insulin or when it doesn’t produce enough insulin to regulate your blood sugar (glucose) level. While several types of diabetes exist, type 2 diabetes is the most common.

For many people diagnosed with diabetes, insulin therapy is necessary to keep blood sugar within a consistent, safe range. While insulin pumps and inhalers are options for some people, self-injections are a standard route of insulin administration for many people living with type 2 diabetes.

By learning more about insulin injections, you can reduce feelings of uncertainty and apprehension and feel more in control of your diagnosis.

Insulin injections involve a needle and syringe or an insulin pen.

Needles and syringes are used to draw insulin from a vial each time you need an injection.

Insulin pens are handheld devices that contain pre-filled insulin cartridges or reservoirs. Like syringes, they have a needle for administration, but a dial on the pen sets your insulin dose. Insulin pens are available in reusable or disposable options.

No matter which option you choose, taking insulin means an injection. Insulin injections are administered just under the skin (subcutaneously), allowing the insulin to enter your bloodstream gradually.

You may feel a sensation similar to a pinprick, followed by burning, coldness, or tingling as the insulin is administered. For many people, insulin injections are mild and don’t cause any significant soreness or pain.

How often you take insulin will depend on factors such as the severity and type of diabetes, your insulin sensitivity, present complications, lifestyle, and current therapy goals.

Insulin types vary based on their speed of effect, when they reach peak effectiveness, and how long they work. Your doctor will decide which type is right for you based on your diagnosis.

Different types of insulin and their common brand names include:

  • Rapid-acting: Starts working in 15 minutes with a peak onset of 1 hour. It’s usually taken immediately before a meal and lasts 2–4 hours. (Fiasp, NovoLog, Apidra, Humalog)
  • Regular/short acting: Starts working within 30 minutes with peak onset after 2–3 hours. Usually taken 30–60 minutes before a meal and lasts for 3–6 hours. (Humulin R, Novolin R, Velosulin R)
  • Intermediate acting: Starts working in 2–4 hours with peak onset between 4 and 12 hours. Lasts between 12 and 18 hours. (Humulin N, Novolin N, ReliOn)
  • Long-acting: Starts working 2 hours after administration and provides consistent dosing with no peak for up to 24 hours. (Tresiba, Levemir, Lantus)
  • Ultra-long acting: Starts working after 6 hours and provides consistent dosing with no peak for 36 hours or longer. (Toujeo)
  • Premixed: A combination of short-acting and intermediate-acting insulin that begins working within 5–60 minutes with varying peaks. Lasts between 10 and 16 hours and is typically taken 10–30 minutes before breakfast and dinner. (Humalog Mix, Novolog Mix, Ryzodeg)

Your prescribed insulin will also have a strength represented by a “U” number, which indicates how many units of insulin are in a milliliter of solution. The most common strength of insulin is U-100, but your doctor may prescribe other strengths, such as U-200, U-300, or U-500.

Your insulin supplies will depend on your choice of injection method: syringe or insulin pen.

If you’re using a syringe to administer your insulin, you’ll need:

  • a syringe (typically comes with needles attached)
  • needles (if not attached to the syringe)
  • your vial of insulin
  • medical disposal container (sharps container)

If you’re using an insulin pen, you’ll need:

  • your insulin pen
  • an insulin cartridge if your pen is not disposable
  • disposable pen needle
  • medical disposal container (sharps container)
  • manufacturer instructions for your specific pen

The choice to use a syringe or a pen is often a matter of personal preference, though cost, insulin dose, and insurance coverage can affect your decision.

Benefits of insulin pens:

  • offer more precise dosing options
  • have smaller, thinner, more comfortable needles
  • are easier to use
  • are less conspicuous

Not all types of insulin can be used with a pen, however, and pens can be more expensive and are not covered by all insurance providers. Some pens may also have batteries that need to be monitored and replaced as needed.

Benefits of syringes:

  • are less expensive
  • can be used with all types of insulin
  • allow full hands-on control of the dosing and administration process
  • do not require any batteries
  • don’t have temperature requirements for storage or transport (though the insulin vial does)
  • may cause more injection site discomfort

Used syringe needles, disposable pen needles, and disposable pens need to go in a medical waste container. These puncture-resistant containers, often called “sharps” containers, prevent accidental needlestick exposures that may pose a health risk.

Check with your health department about the disposal of needleless syringes, empty insulin vials, and pen casings. They can often go in your regular trash, though local restrictions may vary.

Your health department can also instruct you on what to do if you don’t have a sharps container handy. You may be able to place used needles in a heavy-duty plastic container with a secure lid, like an empty laundry detergent bottle.

When your container is full, it may need to be taken to an approved drop-off location like a healthcare facility, local pharmacy, or waste management facility. Your local health department can provide instructions.

How to store insulin

The package insert will let you know how your insulin should be stored.

Most manufacturers recommend insulin be kept in the refrigerator, but your doctor may suggest keeping the bottle you’re using at room temperature if you find injecting cold insulin unpleasant.

Insulin can last up to 1 month at room temperature.

Avoid extreme temperatures when storing insulin, and never keep bottles in the freezer, in direct sunlight, or out in your car.

A to-go bag, or to-go kit, is a small container that holds all the supplies you’ll need for daily or emergency diabetes care. It’s kept separate from your regular supplies, so it’s always ready to go when you leave the house.

Inside the bag, you’ll have:

  • insulin vial or cartridges
  • syringes
  • insulin pens (with extra batteries)
  • blood glucose meter (with extra batteries)
  • lancets
  • glucose and ketone test strips
  • glucagon syringe
  • fast-acting carbohydrates like glucose gel or candy
  • healthy snacks like crackers and peanut butter
  • water
  • medical waste disposal container
  • written instructions for calculating insulin doses
  • list of emergency contacts
  • ice packs to keep insulin within the required temperature range

Even if you usually take your insulin with a pen, adding syringes and an insulin vial to your to-go bag can provide a backup option if there’s a malfunction or another reason the pen can’t be used.

How quickly insulin enters the bloodstream varies depending on the injection site. Insulin injections in the abdomen, for example, tend to work faster than those given in the upper arms, thighs, or buttocks.

Your individual needs and preferences will determine which site your doctor says is the “best” site for you.

Site preparation starts with making sure the area is clean. Soap and water are fine for preparing your skin. If you use an alcohol swab, make sure the area is dry before starting your injection.

To prepare for using a syringe:

  1. Wash your hands.
  2. Check your insulin vial’s expiration date.
  3. Look for any unusual changes in the insulin’s color or consistency.
  4. Gently roll the vial between your palms to mix the insulin if indicated (do not shake).
  5. Remove the lid from the bottle.
  6. Lightly wipe the top of the bottle with an alcohol swab.
  7. Allow the top to dry.
  8. Remove the cap from your syringe.
  9. Pull air into the syringe by pulling back on the syringe plunger. Stop when the plunger top inside the syringe is at the dose you need.
  10. Insert the needle part of the syringe into the rubber top of the insulin vial.
  11. Turn the vial upside down so all the liquid is at the top.
  12. Push out the air from the syringe into the vial.
  13. Pull insulin into the syringe slowly until the top of the plunger is at the correct dose.
  14. Remove the syringe from the vial.

If you’re using an insulin pen:

  1. Familiarize yourself with your pen’s manufacturer’s instructions.
  2. Wash your hands.
  3. Verify the label on your pen to make sure it’s the correct one.
  4. Check the expiration date.
  5. Look for any unusual changes to the color or consistency of the insulin in the pen.
  6. Gently roll the pen between your palms to mix the insulin if indicated (do not shake).
  7. Take the top off the pen to attach the needle.
  8. Prime the pen by turning the dosing dial to the recommended number of units for priming.
  9. Hold the pen upright and gently tap the insulin cartridge to remove air bubbles.
  10. Push the injection button to verify insulin is coming out.
  11. Repeat up to several times if necessary for new pens or cartridges.
  12. Once you’ve verified the pen is primed and working, select your insulin dose using the dosing dial.
  13. Make sure you’re starting at “zero” when inputting your dose.

When your syringe or pen is ready, pinch the skin at your injection location and insert the needle all the way in at a 45-degree angle. In thicker tissue areas, you may need to go in completely upright at a 90-degree angle.

Slowly push the plunger or press the injection button and wait 5 seconds before pulling the needle out.

Some important safety tips regarding insulin injections include:

  • Give insulin injections in the same area of the body to keep insulin absorption consistent.
  • Avoid using the exact same injection site each time.
  • Avoid placing insulin shots on bruised or tender skin.
  • Don’t place injections into hard lumps or bumps under the skin.
  • Try to place injections away from areas with altered circulation, like scars.
  • Don’t use insulin that has an unusual color, cloudiness, or consistency.
  • Don’t use expired insulin.
  • If insulin needs to be mixed, avoid shaking as this could cause large clumps.
  • Don’t use insulin that’s had exposure to extreme temperatures.

Some, but not all, insulin injections are dependent on when you eat. Eating increases the amount of glucose in your bloodstream, and taking insulin around meals directly helps your blood sugar remain steady and within its target range.

Rapid-acting and short-acting insulin is typically taken at mealtime and can be used alongside other, longer-acting forms of insulin (basal insulin) that work throughout the day.

If you take insulin at mealtime, you may have a set dose, called a bolus dose, or you may need to calculate the dose based on which foods you eat and how they affect blood sugar.

Incorporating insulin into your daily life can take some getting used to, but injections don’t have to feel like a daunting obstacle. Syringes and insulin pens are both available, depending on your diagnosis and personal preferences.

Once you become familiar with insulin injections and how they slot into your day, you can get back to doing the activities you enjoy with more peace of mind about diabetes management.