Insulin is a hormone created by the pancreas that plays a key role in regulating blood sugar levels. For individuals with diabetes, either their body doesn’t produce enough insulin, or it can’t use the insulin effectively, leading to high blood sugar levels. This is where insulin therapy comes into play. Insulin injections are vital for people with diabetes to maintain blood sugar control. But when it comes to insulin, the world of treatment options is far from simple. There are various types of insulin, each serving a different function and working at different speeds.

In this article, we will take a deep dive into the different types of human insulin available today, how they work, and how they help individuals with diabetes control their blood sugar levels. By the end, you’ll have a better understanding of which insulin might be suitable for your needs.

What Is Human Insulin?

Before exploring the different types of insulin, it’s essential to understand what human insulin is. Human insulin refers to the form of insulin that is made to be chemically identical to the insulin naturally produced by the pancreas in the human body. Historically, insulin used for diabetes management came from animal sources, such as cows or pigs. However, with advancements in biotechnology, human insulin is now produced using recombinant DNA technology. This means that scientists can create insulin that is virtually identical to the insulin our body naturally produces, making it more effective and compatible for human use.

Human insulin is vital in diabetes management as it helps regulate blood sugar by promoting the uptake of glucose into cells for energy or storage. For those with diabetes, insulin therapy can replace or supplement the insulin their body no longer produces or utilizes effectively.

Types of Human Insulin

Human insulin can be classified into several types based on how quickly it acts and how long its effects last. Broadly, insulin types are categorized into five main categories:

1. Rapid-Acting Insulin
2. Short-Acting Insulin
3. Intermediate-Acting Insulin
4. Long-Acting Insulin
5. Pre-Mixed Insulin

Each of these categories has specific characteristics, such as their onset (how quickly the insulin works after injection), peak (the time during which the insulin works most effectively), and duration (how long the insulin lasts in the body). Let’s explore each type in more detail.

1. Rapid-Acting Insulin

Rapid-acting insulin is one of the most commonly used types of insulin. It is designed to act quickly and cover blood sugar spikes that occur after meals. As the name suggests, rapid-acting insulin works very quickly, and it begins to lower blood sugar within 10 to 30 minutes after injection. It typically reaches its peak effect in about 1 to 2 hours and lasts for approximately 3 to 5 hours.

For people with diabetes, rapid-acting insulin is usually administered right before or immediately after meals to manage blood sugar spikes due to food intake. It is also used in insulin pumps, allowing for a steady infusion throughout the day.

Common examples of rapid-acting insulin include:

• Insulin Lispro (Humalog): This insulin has a very fast onset, making it ideal for controlling blood sugar during meals.
• Insulin Aspart (NovoLog): Another fast-acting insulin that works similarly to insulin lispro.
• Insulin Glulisine (Apidra): This insulin also works quickly to cover meals, with a fast onset and shorter duration than many other insulins.

Rapid-acting insulin is especially useful for people who need to closely control post-meal blood sugar spikes. It can also be combined with long-acting insulin to help provide continuous glucose control throughout the day.

2. Short-Acting Insulin

Short-acting insulin (also known as regular insulin) is slower in onset compared to rapid-acting insulin. It typically starts working within 30 minutes to 1 hour after injection, peaks in about 2 to 3 hours, and lasts for 3 to 6 hours. Short-acting insulin is often used for meal-time blood sugar control, but it takes longer to start working, so it needs to be injected 30 to 60 minutes before a meal to be most effective.

Short-acting insulin has been a cornerstone of diabetes treatment for decades. While it’s less commonly used today in comparison to rapid-acting insulins, it remains an important option for those who require additional blood sugar control between meals or overnight.

Common examples of short-acting insulin include:

• Regular Insulin (Humulin R, Novolin R): This is the classic form of insulin used to control blood sugar levels, especially after meals.

Due to its slower onset, short-acting insulin is typically used for situations where rapid coverage isn’t necessary but consistent, steady insulin release is still required.

3. Intermediate-Acting Insulin

Intermediate-acting insulin offers longer-lasting effects and provides steady control of blood sugar levels over a longer period. It usually starts working within 1 to 3 hours, peaks in about 4 to 12 hours, and lasts for up to 12 to 18 hours. This type of insulin is often used as a basal insulin, providing continuous, long-term coverage to keep blood sugar levels stable between meals and overnight.

Intermediate-acting insulin is commonly mixed with other types of insulin, such as rapid-acting or short-acting insulins, to help balance short-term and long-term insulin needs.

A common example of intermediate-acting insulin is:

• Insulin NPH (Humulin N, Novolin N): NPH insulin is one of the most commonly used intermediate-acting insulins and is often taken once or twice a day.

NPH insulin is suitable for people who need consistent blood sugar control but are not necessarily experiencing major fluctuations in blood sugar. It’s most effective when combined with other types of insulin to control blood sugar during the day and night.

4. Long-Acting Insulin

Long-acting insulin is specifically designed to provide a slow, continuous release of insulin throughout the day and night. It begins working within 1 to 2 hours after injection, has no peak effect, and can last for up to 24 hours or even longer, depending on the specific type. Long-acting insulin is used as basal insulin to maintain a stable insulin level over an extended period, often injected once or twice a day.

Some examples of long-acting insulin include:

• Insulin Glargine (Lantus, Toujeo): This is one of the most commonly prescribed long-acting insulins. It provides stable, long-lasting insulin coverage with minimal risk of hypoglycemia.
• Insulin Detemir (Levemir): Another option for long-acting insulin, Levemir offers a similar duration of action to insulin glargine but may have a slightly shorter duration.
• Insulin Degludec (Tresiba): This insulin offers an ultra-long duration of action, often lasting up to 42 hours, which provides even more flexibility for timing injections.

Long-acting insulin is ideal for people who need steady and consistent insulin levels throughout the day and night. It’s often used in combination with rapid-acting or short-acting insulins to manage post-meal glucose spikes.

5. Pre-Mixed Insulin

Pre-mixed insulin combines both intermediate-acting and rapid-acting or short-acting insulin into a single injection. These insulins are typically used to provide both basal and bolus coverage in one shot, making them convenient for people who don’t want to take multiple injections per day. Pre-mixed insulin can be a convenient option for those who need both short-term and long-term insulin coverage but don’t want to manage multiple types of insulin.

Examples of pre-mixed insulin include:

• Humulin 70/30 (70% NPH and 30% Regular insulin)
• Novolin 70/30 (70% NPH and 30% Regular insulin)
• Humalog 75/25 (75% insulin lispro protamine and 25% insulin lispro)

Pre-mixed insulin can be used by people who have relatively stable blood sugar levels throughout the day. However, for those with highly fluctuating blood sugar, other types of insulin may offer more flexibility and control.

Choosing the Right Type of Insulin

The type of insulin that’s best for you depends on several factors, including your lifestyle, how your body reacts to insulin, your blood sugar levels, and how often you need to manage blood sugar spikes.

• Rapid-acting insulin is ideal for managing blood sugar spikes after meals.
• Short-acting insulin provides effective blood sugar control but takes longer to work.
• Intermediate-acting and long-acting insulins offer continuous coverage and help maintain stable blood sugar levels over time.
• Pre-mixed insulin is convenient for those who need both basal and bolus insulin coverage.

Your healthcare provider will work with you to determine which insulin regimen works best based on your specific needs, helping you achieve optimal blood sugar control. Additionally, the use of insulin pumps or continuous glucose monitoring systems may be recommended to improve insulin delivery and monitoring for more effective diabetes management.

Conclusion

There are many types of human insulin available, each designed for different purposes and to meet the specific needs of people with diabetes. Rapid-acting, short-acting, intermediate-acting, long-acting, and pre-mixed insulins all play important roles in managing blood sugar levels and helping individuals with diabetes maintain optimal health.

By understanding the differences between these types of insulin, individuals with diabetes can better manage their condition and work with their healthcare providers to create a treatment plan tailored to their unique needs. Whether you need insulin to manage blood sugar spikes or provide consistent, long-term coverage, there is a type of insulin that can help you live a healthier, more balanced life.