What Is Insulin Therapy?
Insulin is a hormone that your pancreas makes to allow cells to use glucose. When your body isn't making or using insulin the way it should, you can take manufactured insulin to help control your blood sugar. Most people take insulin by injecting it into the skin, though there’s also a version that you inhale. If you have type 1 diabetes, you need insulin because your pancreas no longer makes the hormone. If you have type 2 diabetes, you may need insulin, though many people with this form of the disease can control their blood sugar without it.
What Are the Different Types of Insulin?
Many forms of insulin treat diabetes. They're grouped by how fast they start to work and how long their effects last.
The types of insulin include:
Rapid-acting: This type of insulin starts to work in about 15 minutes and lasts for 1 to 5 hours, depending on which type you use. You take rapid-acting insulin before a meal and it’s usually paired with a longer-acting form of insulin.
Short-acting: Also called regular insulin, this form takes about 30 minutes to work fully and lasts 3 to 8 hours. You should take short-acting insulin 30 to 60 minutes before a meal.
Intermediate-acting: Often combined with rapid- or short-acting insulin, intermediate-acting insulin covers your insulin needs for about half a day. Some people use it overnight. Intermediate-acting insulin starts working in an hour or two, and takes 2 to 4 hours to reach peak effect.
Long-acting: This form provides a full day of insulin coverage. You will probably use a shorter-acting type of insulin with it.
Premixed: There are several forms of premixed insulin, including Humulin, Novolog, and others. These varieties combine short-acting and intermediate-acting insulins in one bottle or insulin pen, which some people find easier to administer.
What is glargine insulin used for?
Glargine insulin is a type of long-acting insulin, which lasts for about 1 day.
How to Take Types of Insulin
There are several options for taking insulin. Each method for administering insulin has its own technique. Your doctor can help you choose the one that works best for you.
Ways to take insulin
The major options for taking insulin include:
Syringes: Most people who use insulin administer it with a syringe, which is a tube attached to a needle that can be used to inject medicine into the body. To prepare the syringe, place the needle into a bottle of insulin and withdraw the right dose. Then you or your caregiver insert the needle into your body and inject the insulin.
Pens: Similar to a syringe, an insulin pen uses a needle to inject the medicine into your body. But pens are prefilled with insulin, so you don’t need to fill them from a bottle. Some insulin pens are disposable, while others can be reused by inserting a new cartridge of insulin. Pens are more convenient than syringes but more expensive to use.
Pumps: An insulin pump is a small computer that you wear on your body. It has a container full of insulin and a hose with a needle on the end, which you insert into your body. You can instruct the computer to provide a low, steady stream of insulin all day or deliver a “bolus” of insulin after you eat a meal to control your blood sugar.
Inhalers: If you use rapid-acting insulin, you have the option to inhale it instead of injecting. To use Afrezza, which has been available in the United States since 2015, you place an oral inhaler to your mouth and breathe the medicine into your lungs.
Best insulin injection sites
The place on the body where you give yourself the shot may matter. You'll absorb insulin the most evenly when you inject it into your belly. The next best places to inject it are your arms, thighs, and buttocks. Make it a habit to inject insulin at the same general area of your body, but change up the exact injection spot. Some doctors recommend spacing out injection sites by at least the width of one finger or slightly more if you use an insulin pump. This helps lessen scarring under the skin. If you develop hard lumps in your injection site, you may have scarring and need to use a different injection site.
Which is the least painful spot to inject insulin?
One small study found that people with diabetes considered insulin injections in the belly to be less painful than injections in the upper arm or thigh. However, these patients also said that they didn’t think insulin injections were very painful to begin with. The belly is also the best place to inject insulin, since you absorb the medicine more evenly. Be sure to insert the needle at least a few inches from your belly button.
What Type of Insulin Is Best for My Diabetes?
Your doctor will work with you to prescribe the type of insulin that's best for you and your diabetes. Making that choice will depend on many things, including:
- How you respond to insulin. How long it takes the body to absorb it and how long it remains active varies from person to person.
- Lifestyle choices. The type of food you eat, how much alcohol you drink, or how much exercise you get will all affect how your body uses insulin.
- Your willingness to give yourself multiple injections per day
- How often you check your blood sugar
- Your age
- Your goals for managing your blood sugar
Your doctor may prescribe more than one type. You might need to take insulin more than once daily, to space your doses throughout the day, or to add other medicines.
Afrezza, a rapid-acting inhaled insulin, is FDA-approved for use before meals for both type 1 and type 2 diabetes. The drug peaks in your blood in about 15-20 minutes and it clears your body in 2-3 hours. It must be used along with long-acting insulin in people with type 1 diabetes.
The chart below lists the types of injectable insulin with details about onset (the length of time before insulin reaches the bloodstream and begins to lower blood sugar), peak (the time period when it best lowers blood sugar) and duration (how long insulin continues to work). These three things may vary. The final column offers some insight into the "coverage" provided by the different insulin types in relation to mealtime.
| Type of Insulin & Brand Names | Onset | Peak | Duration | Role in Blood Sugar Management |
| Rapid-Acting | ||||
| Lispro (Humalog) | 15-30 min. | 30-90 min | 3-5 hours | Rapid-acting insulin covers insulin needs for meals eaten at the same time as the injection. This type of insulin is often used with longer-acting insulin. |
| Aspart (Novolog) | 10-20 min. | 40-50 min. | 3-5 hours | |
| Glulisine (Apidra) | 20-30 min. | 30-90 min. | 1-2 1/2 hours | |
| Short-Acting | ||||
| Regular (R) or novolin | 30 min.-1 hour | 2-5 hours | 5-8 hours | Short-acting insulin covers insulin needs for meals eaten within 30-60 minutes. |
| Velosulin (for use in the insulin pump) | 30 min.-1 hour | 1-2 hours | 2-3 hours | |
| Intermediate-Acting | ||||
| NPH (N) | 1-2 hours | 4-12 hours | 18-24 hours | Intermediate-acting insulin covers insulin needs for about half the day or overnight. This type of insulin is often combined with a rapid- or short-acting type. |
| Long-Acting | ||||
| Insulin glargine (Basaglar, Lantus, Toujeo) | 1-1 1/2 hours | No peak time. Insulin is delivered at a steady level. | 20-24 hours | Long-acting insulin covers insulin needs for about one full day. This type is often combined, when needed, with rapid- or short-acting insulin. |
| Insulin detemir (Levemir) | 1-2 hours | 6-8 hours | Up to 24 hours | |
| Insulin degludec (Tresiba) | 30-90 min. | No peak time | 42 hours | |
| Premixed* | ||||
| Humulin 70/30 | 30 min. | 2-4 hours | 14-24 hours | These products are generally taken two or three times a day before mealtime. |
| Novolin 70/30 | 30 min. | 2-12 hours | Up to 24 hours | |
| Novolog 70/30 | 10-20 min. | 1-4 hours | Up to 24 hours | |
| Humulin 50/50 | 30 min. | 2-5 hours | 18-24 hours | |
| Humalog mix 75/25 | 15 min. | 30 min.-2 1/2 hours | 16-20 hours | |
| *Premixed insulins combine specific amounts of intermediate-acting and short-acting insulin in one bottle or insulin pen. (The numbers following the brand name indicate the percentage of each type of insulin.) | ||||
When to Take Insulin
Follow your doctor's guidelines on when to take your insulin. The time span between your shot and meals may vary depending on the type you use.
In general, though, you should coordinate your injection with a meal. You want to time your shot so that the glucose from your food gets into your system at about the same time that the insulin starts to work. This will help your body use the glucose and avoid low blood sugar reactions. From the chart above, the "onset" column shows when the insulin will begin to work in your body. You want that to happen at the same time you're absorbing food. Good timing will help you avoid low blood sugar levels.
- Rapid acting insulins: About 15 minutes before mealtime
- Short-acting insulins: 30 to 60 minutes before a meal
- Intermediate-acting insulins: Up to 1 hour prior to a meal
- Premixed insulins: Depending on the product, between 10 minutes or 30 to 45 minutes before mealtime
Exceptions to Insulin Dosing and Timing
Long-acting insulins aren’t tied to mealtimes. You’ll take detemir (Levemir) once or twice a day no matter when you eat. And you’ll take glargine (Basaglar, Lantus, Toujeo) once a day, always at the same time. Deglutec is taken once a day, and the time of day can be flexible. But some people do have to pair a long-acting insulin with a shorter-acting type or another medication that does have to be taken at mealtime.
Rapid-acting products can also be taken right after you eat, rather than 15 minutes before mealtime. You can take some of them at bedtime.
For more information about when to take insulin, read the "dosing and administration" section of the insulin product package insert that came with your insulin product, or talk with your doctor.
Types of Insulin Side Effects
The major side effects include:
- Low blood sugar
- Weight gain when you first start using it
- Lumps or scars where you've had too many injections
- Rash at the site of injection or, rarely, over your entire body
With inhaled insulin, there's a chance that your lungs could tighten suddenly if you have asthma or the lung disease COPD.
Storing Injectable Insulin
Always have two bottles of each type you use on hand. You don't need to refrigerate vials of insulin that you're using. A good rule of thumb is that if the temperature is comfortable for you, the insulin is safe. You can store the bottle that you're using at room temperature (not higher than 80 F) for 30 days. You don't want it to get too hot or too cold, and keep it out of direct sunlight.
Keep your extra backup bottles in the refrigerator. The night before you're going to start using a new bottle, take it out and let it warm up. Don't let your insulin freeze.
Always look at your insulin inside the bottle before you draw it into the syringe. Rapid-acting, short-acting, and certain long-acting types should be clear. Other forms may look cloudy, but they shouldn't have clumps.
If you carry a bottle with you, be careful not to shake it. That makes air bubbles, which can change the amount of insulin you get when you withdraw it for an injection.
For insulin pens, check the package insert for storage instructions.
Storing Inhaled Insulin
Check the directions on the package. You should keep a sealed package in the refrigerator until you're ready to start using it. If you don't, you must use it within 10 days.
You can refrigerate packages you've opened, but let a cartridge warm up to room temperature for 10 minutes before you use it.
Takeaways
There are many forms of insulin, which differ by how long it takes them to start working, reach their peak effectiveness, and stop working. Your doctor can help you determine which insulin or combination of the different types of insulin is right for you. There are also different ways to take insulin, so you can choose the option that you find convenient and easiest to use.
Types of Insulin FAQs
How many types of human insulin are there?
There are five general types of insulin made for treating diabetes. All types of insulin help cells use glucose for energy. The different types of insulin vary according to how rapidly they go to work and last in the body. The five main types of insulin are:
- Rapid-acting insulin is usually taken right before a meal and stays active for several hours.
- Short-acting insulin is usually taken before a meal, too, but takes somewhat longer to work.
- Intermediate-acting insulin works for about half a day.
- Long-acting insulin provides about a day’s worth of coverage.
- Premixed insulin is a combination of intermediate- and short-acting insulin.
How long does Novolog last?
Novolog (the brand name for insulin aspart) lasts 3 to 5 hours. Novolog is a rapid-acting insulin. It begins working in as little as 10 minutes and reaches peak effectiveness in 40 to 50 minutes.
Which insulin is best?
No form of insulin is best. Each category of insulin has unique properties that determine how long it takes to work, reach its peak effectiveness, and stop working. Using a combination of different types of insulin can help you control blood sugar.
Does type 2 diabetes require insulin?
People with type 2 diabetes who can’t control their blood sugar by making lifestyle changes and taking other diabetes treatments may need to use insulin. Some people with type 2 diabetes use insulin and other diabetes treatments.
Is Lantus a long-acting insulin?
Lantus is a long-acting insulin. Its effects last up to 1 day. There are other types of long-acting insulins, including Basaglar and Toujeo.
