What is insulin?

How is basal-bolus insulin therapy in the hospital done?

This treatment uses two types of insulin shots. The shots may be given with an insulin pen or with a regular needle.

  • Basal shot: This is long-acting insulin that you get once or twice a day. It gives a small but constant stream of insulin. This insulin helps process the sugar in your blood when you're not eating.
  • Bolus shot: This is short-acting insulin that you get at mealtime. It gives your body an extra burst of insulin. This insulin helps process the new sugar you get when you eat. You may get extra bolus shots between meals.

Your blood sugar will be tested 4 or 5 times a day to be sure it's not too high or too low.

If you have diabetes, you may already use insulin shots and have a target range. But in the hospital these may be different. After you leave the hospital, check with your doctor to see if your insulin routine needs to change.


Insulin is a hormone produced in the pancreas that allows sugar (glucose) to enter body cells, where it is used for energy. It also helps the body store extra energy in muscle, fat, and liver cells.

Diabetes develops if the body does not produce enough insulin, does not use insulin properly, or both.

Types of insulin

Insulin is used to treat people who have diabetes. How quickly insulin starts to work and how long it lasts will be different depending on the type of insulin you use. Other factors that can affect insulin and your blood sugar are exercise, diet, illness, some medicines, stress, the dose, how you take it, or where you inject it. The table below is a general guide. Your results may be different.

Insulin is available in several strengths. U-100 is the most common. U-100 means there are 100 units of insulin in one milliliter of fluid. Other strengths include U-200, U-300, and U-500. For example, U-500 is five times more concentrated than U-100 regular insulin. Be sure to check the concentration of your insulin so you take the right amount.

Insulin is made by different companies. Ask your doctor or diabetes educator about the type of insulin you have and how to use it. See the table below for types of insulin and some examples.

Types of insulin
​ ​ ​ ​ ​
Rapid-acting insulins (bolus insulin) are usually taken at the start of a meal.

Insulin aspart (Fiasp)

Insulin glulisine (Apidra)

Insulin lispro (Humalog)

Clear10–20 minutes2–4 hours
Rapid-acting insulin also comes in a form that can be inhaled through the mouth.Insulin human inhalation powder (Afrezza)Contained in a cartridge12 minutes1½–3 hours
Short-acting insulins (bolus insulin) are usually taken a short time before a meal.

Insulin regular (Humulin-R U-100, Novolin R, and Novolin R ReliOn)

Clear30–60 minutes5–8 hours
Intermediate-acting insulins (basal insulin) are usually taken between meals and at bedtime.

Insulin NPH (Humulin-N, Novolin-N, and Novolin ReliOn)

Cloudy1–3 hoursUp to 24 hours
Long-acting insulins (basal insulin) are usually taken between meals and at bedtime.

Insulin detemir (Levemir)

Insulin glargine (Lantus and Basaglar)

Insulin regular (Humulin R U-500)

Clear60–90 minutes (30 minutes for U-500)Up to 24 hours
Ultra long-acting insulins (basal insulin) are usually taken between meals and at bedtime.

Insulin degludec (Tresiba)

Insulin glargine (Toujeo)

Clear1 hour (up to 6 hours for insulin glargine)36–42 hours

Mixtures of insulin can sometimes be combined in the same syringe, for example, intermediate-acting and rapid- or short-acting insulin. Not all insulins can be mixed together.

For convenience, there are premixed rapid- and intermediate-acting insulins. These come in a premixed ratio, such as 75/25, 70/30, and 50/50. For example, 75/25 means the mixture is 75% intermediate-acting insulin and 25% rapid-acting insulin. They are usually taken 2 times a day at the start of a meal. These insulins look cloudy. The insulin will start to work as quickly as the fastest-acting insulin in the combination. It will last as long as the longest-acting insulin. Examples include:

  • Insulin regular and insulin NPH.
  • Insulin lispro and insulin lispro protamine.
  • Insulin aspart and insulin aspart protamine.

How can you work through your emotions about taking insulin?

For many people, the whole idea of taking insulin can feel overwhelming. It's a big change. Working through your emotions about taking insulin can help.

Ask yourself how you feel about insulin.

Do shots scare you? Are you worried about the hassle or cost? Consider asking your doctor about other ways to take insulin, such as an insulin pen. They're easier than giving a shot with a syringe.

Think about the benefits of taking insulin.

For example, it will help keep your blood sugar under control. This may help you avoid other problems.

Imagine you've been taking insulin for a while.

Think how you'll feel in a few months. Over time, you'll probably get used to the routine or be less fearful of needles. How will that feel?

Write down your feelings.

In 3 months, look back at what you wrote. You might be surprised to see all the ways you're managing better now.

What is the insulin-to-carbohydrate ratio?

This ratio shows how much insulin is needed to keep your blood sugar at your target level. It's based on how many grams of carbs you eat in a meal or snack. Your doctor or diabetes educator can help you find your ratio by tracking what you eat and testing your blood sugar after meals.

How to make it easier to take insulin

There are a lot of reasons it can be hard to take insulin. It's not fun. And it can be a challenge to make it a regular part of your routine. At the same time, you know that insulin does a lot to help control your diabetes. It can also help slow or prevent future problems.

So it can pay off to find ways to make it easier to take insulin. Here's how to get started.

  1. Figure out what makes it hard for you to take insulin.

    This can help you uncover ways that make it easier.

    For some people, it's hard to find the time to take insulin. Others may be afraid to give themselves a shot.

    Time and fear are two common things that can get in the way of taking insulin. But those aren't the only things that can make it hard. For example, some people feel disappointed that they can't control their diabetes in other ways.

  2. Write down what might make it easier for you.

    For example, if time is a problem for you, it might help to:

    • Talk with your health care team about the types of insulin you take.
      • Some types of insulin may be given right before meals, which can help make it easier.
      • Some types can be combined. So you may be able to take fewer shots.
    • Ask your health care team about a diabetes bag. Having a small bag that's designed to hold your supplies can make it easier to leave the house with everything you need.
    • Remember that your routine will get easier and faster with practice.

    If it scares you to give yourself shots, it might help to:

    • Talk to someone else about how it got easier for them.
    • Teach someone else to give you the shots, or even to prepare the shots for you. This can be especially important if you have hand or eye problems.
    • Try using a special type of insulin "pen." The pens have a smaller needle. Some people find them less painful than shots. An insulin pen may help you give yourself more accurate doses. It can also be easier to carry.

    If you need more ideas about how to make taking insulin a little easier, your doctor or a certified diabetes educator may be able to help.

  3. Try out the best solution.

    Think through the pros and cons of each solution. Which one do you think will work best for you?

    After you've decided, think through what will make you more confident about following through with your new solution.

Diabetes: Insulin's Role

How is insulin used to treat type 1 diabetes?

Insulin helps keep your blood sugar level within a target range. It can be taken as a shot (injection) or through an insulin pump. Rapid-acting insulin is also available as a powder that you inhale.

Most people who have type 1 diabetes take a combination of types of insulin. For instance, they may take a long-acting insulin once or twice a day and a rapid-acting insulin before each meal. The amount and type of insulin needed varies for each person.

  • The amount and type of insulin you need changes over time. It depends on your age, hormones (such as during rapid growth or pregnancy), and changes in exercise routine.
  • You may need higher doses during times of illness or emotional stress.

Never skip a dose of insulin without the advice of your doctor.

How to give an insulin injection into the arm

  1. Clean the injection site.

    Make sure the area of skin where you will give the shot is clean. If you use alcohol to clean the skin before you give the injection, let it dry. Remove the cap from the syringe.

  2. Pinch up the skin.

    Using your knee, push up the back of your arm to create a "pinched-up" area of skin.

  3. Push the needle into the skin.

    Push the needle all the way into the pinched-up area.

  4. Relax the skin.

    Lower your knee slightly so that the back of your arm is no longer pinched up.

  5. Inject the insulin.

    Push the plunger of the syringe all the way in.

  6. Throw the needle away safely.

    Throw away the needle in a sharps container or other solid plastic container. You can get a sharps container at your pharmacy.

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