6 Types of Insulin and How They Work

If you need insulin for diabetes, you have choices.

As of March 2022, six types of insulin exist to treat diabetes. Your insulin choices vary by how soon they start to work (onset), when they reach their full effect (peak), and how long they can stay in your system (duration).

The types of insulin you can choose to treat your diabetes include rapid-acting, short-acting, intermediate-acting, long-acting, ultra-long-acting, and pre-mixed. You can take many of them in various ways, including inhalers, small needles, or pumps.

Read on to learn more about the types and how to choose the one that's right for you.

Pharmacist testing older adult patient for diabetes

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Why You Need Insulin

Your pancreas makes typically enough insulin to regulate your blood sugar levels, so they don't get too low or too high. When your pancreas doesn't make enough, as in type 1 or type 2 diabetes, your blood sugar levels become uncontrolled. They can get dangerously high, leading to sometimes-fatal complications.

Everyone with type 1 will need insulin regularly. Many people with type 2 (the type 90%-95% of people have) will also require insulin. If you have type 2, you may be able to manage your blood sugar levels with lifestyle changes and use insulin as an addition.

Different types of insulin exist, from biosimilars to unbranded biologic insulin, which is the same thing as the brand but without the label.

You may have to take more than one type, and your needs may change over time and vary depending on your type of diabetes. If you have type 1 diabetes, you'll likely need a combination of insulin types. There are also different strengths. The most common is U-100.

Your healthcare provider will help you choose based on several factors, including:

  • Your age
  • How well you can manage your blood sugar
  • Your activity level
  • Your diet
  • How long it takes your body to absorb insulin, and how long it works
  • Cost and affordability

What Is Biosimilar Insulin?

Biosimilar insulin isn't generic insulin. It's a U.S. Food and Drug Administration (FDA)-approved product similar to an original type of insulin. The main difference is the inactive portion. Healthcare providers may sometimes prescribe them because they cost less.

Rapid-Acting Insulin

What it's called: Humalog (lispro), NovoLog (aspart), Apidra (glulisine), Afrezza, Fiasp (aspart), Lyumjev (lispro-aabc)

How it works: You take rapid-acting insulin just before or after meals to control spikes in blood sugar. This type is typically used with longer-acting insulin.

It often works in 15 minutes, peaks in an hour, and lasts two to four hours. There's an inhaled variety that works in 10-15 minutes, peaks in 30 minutes, and lasts for three hours.

"You can take it a few minutes before eating or as you sit down to eat, and it starts to work very quickly," Manisha Chandalia, MD, past director of the Stark Diabetes Center at the University of Texas Medical Branch in Galveston, told Health.

Short-Acting Insulin

What it's called: Humulin R U-100, Novolin R, Novolin R ReliOn

How it works: Short-acting insulin (sometimes called "regular" insulin) covers your insulin needs during meals. You take it about 30 minutes to an hour before a meal to help control blood sugar levels.

This type of insulin takes effect in about 30 minutes and peaks after two to three hours. Its effects tend to last about three to six hours.

"The biggest advantage of short-acting insulin is that you don't have to take it at each meal. You can take it at breakfast and supper and still have good control because it lasts a little longer," said Dr. Chandalia.

Intermediate-Acting Insulin

What it's called: Humulin N (NPH), Novolin N (NPH), Novolin N ReliOn

How it works: Intermediate-acting insulin can control blood sugar levels for 12 to 18 hours, so it can be used overnight. It begins to work within two to four hours and peaks between four and 12 hours, depending on the brand.

"Intermediate-acting insulin offer baseline insulin coverage and can be used with short-acting insulin or rapid-acting insulin," explained Dr. Chandalia.

Long-Acting Insulin

What it's called: Basaglar (glargine), Lantus (glargine), Humulin R U-500, Lantus (glargine), Levemir (detemir), Semglee vial (glargine-yfgn)

How it works: Long-acting insulin has an onset of two hours and lasts up to 24 hours without peaking. This insulin type tends to cover your insulin needs for a full day. It is commonly taken at bedtime but can be taken at any time of the day if you keep that time consistent.

"These long-acting insulins provide 24-hour coverage and have been helpful at achieving good blood sugar control in type 2 diabetes with just one shot," said Dr. Chandalia.

Ultra-Long-Acting Insulin

What it's called: Toujeo, Tresiba (degludec)

How it works: Ultra-long-acting insulin is insulin that is still working more than 24 hours after you inject it. Your body breaks down this type of insulin more slowly, leading to a slower release. It usually takes six hours to begin working, doesn't peak, and lasts up to 36 hours.

Pre-Mixed Insulin

What it's called: Humulin 70/30, Novolin 70/30, Novolin 70/30 ReliOn, NovoLog 70/30, Humulin 50/50, Humalog mix 75/25, Humalog mix 50/50, Insulin Aspart Protamin and Insulin Aspart 70/30, Insulin lispro protamine and insulin lispro 75/25

How it works: This type of insulin combines intermediate- and short-acting insulin. You usually take it twice a day before meals. You take it 10 minutes to 30 minutes before breakfast and dinner.

Pre-mixed insulin takes effect in 5 to 60 minutes, and its peak times vary. Its effects last from 10 to 16 hours. Pre-mixed insulin was designed to be more convenient. However, not everybody has the same insulin requirements, so the pre-mixed categories don't apply to everyone.

Insulin Delivery

There are various insulin types, and there are also many more ways to deliver the medication than ever. Insulin can be taken via an injector pen, a tiny needle, an inhaler, or an insulin pump.

In whichever way you take it, insulin can be a lifesaver. It lowers high blood sugar, preventing blindness, nerve damage, kidney damage, and other diabetes-related complications. And the more careful you are about taking insulin correctly (don't skip doses), the less likely you will have health problems.

A Quick Review

If you have diabetes, you have a lot of types of insulin to choose from. Manufacturers keep adding to the variety. They offer everything from mixes that start working in five minutes to ultra-long-acting varieties that don't kick in for six hours and last more than a day. Talk to your healthcare provider about the type of insulin you need, including strength and delivery method (inhaler, pump, pen, or injection).

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12 Sources
Health.com uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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