Insulin for Type 2 Diabetes

Insulin may be something you tend to associate with type 1 diabetes, but not type 2. The reality is that, as you age, your pancreas can essentially get tired, and the beta cells that make insulin (the hormone that helps to normalize blood sugar) can die or get sluggish. When this happens, over time, controlling your blood sugar with diet, exercise, and oral medication alone is no longer enough to manage your type 2 diabetes effectively. That means that you need to take insulin that is manmade.

You might also need insulin if your blood sugars were extremely high at diagnosis, if you are very insulin resistant, or if you are unable to control your blood sugar with oral medicine, diet, and exercise. Depending on your situation, you might only be on insulin for a short period of time to normalize blood sugars. Others may need to take it for longer. Everyone's diabetes medication regimen is tailored to their specific needs. If you are starting insulin, discuss why it's recommended, what type you are set to take, and how to use it with your healthcare provider.

What Exactly Does Insulin Do?

Insulin plays many roles, but its main one is to help balance blood sugar. It promotes the absorption of sugar from the bloodstream into muscle, liver, and fat cells, where it is used for energy production or stored for future energy needs.

When we eat carbohydrates, the pancreas kicks out a large load of insulin to bring down our blood sugar. And when we are at rest, the pancreas produces a small amount of insulin all day long to keep blood sugars stable. People who do not have diabetes make the perfect amount of insulin to control blood sugar by themselves. People with diabetes, however, don't have the ability to do that. Sometimes, people with type 2 diabetes can control their blood sugars with oral medications, diet, and exercise. Sometimes, they need to either take a long-acting insulin, a mealtime insulin, or a combination of both to get the job done.

What Types of Insulin Are Available?

There are several different types of insulin available:

  • Long-acting insulin
  • Rapid-acting insulin
  • Short acting insulin
  • Intermediate-acting insulin
  • Mixed insulin

Each type of insulin is created for a specific purpose. Some are meant to lower after-meal sugars, others to cover blood sugar throughout the day, and others are created to do both. Sometimes people need to take one type of insulin. Other times, people need to take two types. Insulin differs in onset (how long it takes for the insulin to start working after you inject it), peak (when the insulin is working its strongest to lower your blood sugar), and duration (how long the insulin lasts in your body).

Some people with diabetes need to take two different types of insulin to control their blood sugar. If they are unable to use two different pens (or other delivery methods), mixtures of intermediate-acting insulin and either rapid-acting insulin or short-acting insulin are available. You can not combine long-acting insulin with rapid- or short-acting insulin into one mixture. Pre-mixed insulin isn't always the most reliable way to control blood sugar, but is an alternative to taking multiple injections and maybe easier for those people who are older or are unable to quite master two separate insulin injections. These types of insulin mixtures are not great options for people who skip meals or have erratic eating schedules.

Your doctor will let you know what type of insulin you need to take and why. Sometimes your insurance plan prefers a specific type of insulin. If your cost of insulin is too high, you may want to check with your insurance carrier to make sure you are taking the preferred insulin.

Here are some different types of insulin and how they compare:

Type of Insulin Onset Peak Duration Examples
Rapid-acting insulin 10 to 30 minutes 30 to 90 minutes 3 to 5 hours

Apidra (insulin glulisine)

Humalog (insulin lispro)

NovoLog (insulin aspart)

Short-acting insulin 30 to 60 minutes 2 to 5 hours Up to 12 hours

Humulin R (regular insulin)

Novolin R (regular insulin)

Intermediate-acting insulin 1.5 to 4 hours 4 to 12 hours 12 to 16 hours, but can last as long as 24 hours

Humulin N (NPH insulin)

Novolin N (NPH insulin)

Long-acting insulin 1 hour minimal 20 to 24 hours

Lantus (insulin glargine)

*Levemir (insulin detemir)

Toujeo (lantus in its concentrated form)

**Tresiba (insulin degludec)

Mixed insulin 5 to 60 minutes varies 10 to 16 hours

Humalog 50/50 (50% intermediate-acting + 50% rapid-acting)

Humalog 75/25 (75% intermediate-acting + 25% rapid-acting)

Humulin 50/50 (50% intermediate-acting + 50% short-acting)

Humulin 70/30 (70% intermediate-acting + 30% short-acting)

Novolin 70/30 (70% intermediate-acting + 30% short-acting)

NovoLog 70/30 (70% intermediate-acting + 30% rapid-acting)

*This medication can be variable in how long it lasts in the body; people on large doses may need to take multiple injections.

**Some studies suggest you can vary injection times of this drug and still have the same blood sugar control.

How Do I Take Insulin?

Insulin can be delivered through many different types of devices. The most common one for people with type 2 diabetes used today is called an insulin pen. Other devices include a vial and syringe, an insulin pump, an insulin patch pump, and inhaled insulin.

Insulin pen: An insulin pen is a device that is used to deliver insulin using a small, attachable needle. Pens can be used to deliver a variety of long-acting and rapid acting insulin types, as well as premixed insulin formulations. They get their name because they are about the size and shape of ink pens.

The pen can either be pre-filled with insulin (these are disposable) or you can be prescribed a reusable pen. If you have a reusable pen, you must load it with a cartridge of insulin (sold separately in boxes of five cartridges). Depending on the size of your doses, a cartridge may give you enough insulin to last for several days of injections. When the cartridge is empty, you throw it away and load a new cartridge. When you are finished with a disposable insulin pen, you simply throw it away.

Before injecting yourself with insulin, you must attach the needle. You must use a new needle for each injection. All pens that are not in use should be refrigerated. Once you've opened a pen and begin to use it, you can keep it outside of the refrigerator. Most pens last about 28 to 30 days, depending on the pen (always read the package insert). Aim to avoid exposing pens to extreme temperatures and make sure you dispose of all sharps in either a sharps container or a puncture proof container. Ask your certified diabetes educator or physician to teach your to properly inject your insulin dose.

Vial and syringe: Insulin can be distributed via a vial or a small glass container. Syringes vary in how much insulin they hold, as well as how thick and long the needle is. You will insert your needle (or syringe) into the vial to pull out enough insulin. Your doctor, nurse, or certified diabetes educator can show you how to do this. This can sometimes be difficult for people with dexterity issues or elderly people who have a hard time reading small numbers. There is a system to doing this; if not done correctly, you can pull up the wrong amount of insulin, which can affect your blood sugars.

Insulin pump: An insulin pump is a small, pager-sized device that delivers a continuous dose of insulin through a cannula to cover your baseline or background insulin needs. It can also deliver insulin to cover your meal time sugars, which is referred to as bolusing. In order for people with type 2 diabetes to be eligible for an insulin pump, they need to meet specific requirements.

Insulin patch pump: An insulin patch pump is a portable, tubeless, disposable insulin delivery system (like a mini pump). It is very light in weight, about 0.7 to 1.8 ounces, and is 2.4 inches long, 1.3 inches wide and half an inch thick. It was approved by the Food and Drug Administration (FDA) in 2010 and has been marketed in the United States since 2012. It acts similarly to an insulin pump in that it delivers a continuous amount of basal insulin during a 24-hour period and also delivers bolus insulin (insulin that helps to cover after meal blood sugars). It comes in a variety of doses.

Inhaled insulin: Afreeza is a rapid-acting insulin that is used to reduce meal time blood sugars. It is not recommended in people who smoke. This inhaled insulin is not prescribed often, as it is expensive and can only deliver four, eight, and 12 units or insulin at a time, which can be inconvenient for those who are on more or less insulin.

  • Afreeza Insulin Powder

When Should I Take Insulin?

The timing of insulin will depend on several things, including what type of insulin you are taking, your blood sugar number and targets, and your meal schedule. Some people with type 2 diabetes only need to take one injection a day, whereas others may need to take multiple insulin injections to get their blood sugars to target. Your physician will discuss with you how many injections you need per day and when you should take them to reach your target blood sugar. If you're ever unsure, ask.

What Are the Potential Side Effects of Insulin?

The main side effect of insulin is low blood sugar, known as hypoglycemia. Low blood sugar can occur if you take too much insulin, if you take insulin and exercise for a long period of time, or if you take insulin without eating enough (or at all). Low blood sugar is defined as a sugar of less than 70 md/dL. Symptoms of a low blood sugar include shaking, sweating, confusion, and dizziness.

It's important to know how to correct a low blood sugar. If your blood sugar is low, treat it with 15 grams of fast acting carbohydrate, such as four ounces of juice, four glucose tablets, five hard candies, or eight ounces of skim milk. Re-check your blood sugar and make sure it has risen above 70mg/dL. If it hasn't, repeat the treatment. If it has risen, you may need to have a small snack with carbohydrate and protein to prevent it from falling again. If you experience low blood sugars often, you should contact your healthcare provider. You may need to change your insulin dose.

Another side effect of insulin is weight gain. Insulin is a fat-storing hormone. Sometimes, when your blood sugars are elevated and they start to normalize, your body begins to use the glucose your are feeding it and you can gain weight. You may also gain weight if you are on a large amount of insulin. The best way to try to stabilize your weight is to aim to eat a healthy diet and exercise.

Some insulin may have other side effects such as reactions at the injection site. Be sure to read medication package inserts and discuss side effects of specific insulin with your healthcare provider.

Type 2 Diabetes Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

Doctor Discussion Guide Man

A Word From Verywell

Starting insulin may sound scary, but it's just the body's way of telling you that it needs some help. Whether you are starting a long-acting insulin, a mealtime insulin, or some other combination of insulin, once you get the hang of things, you'll see that it's not as difficult or scary as you once thought. And if you have needle fear, it may comfort you to know that needles today are very thin and short. Change can be tough, but you can do it.

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Article Sources

  • American Association of Diabetes Educators. Insulin Injection-Know How.
  • Joslin Diabetes Center. Insulin A-Z: A Guide of Different Types of Insulin.
  • Novo Nordisk. Tresibs.
  • Sanofi -Aventis. Toujeo.