Types of Insulin

People with diabetes have been able to inject insulin since the 1920s when scientists began extracting insulin from the pancreases of cows and pigs. Phew, we’ve come a long way in the last century! Since the 1980s, pharmaceutical companies have been able to manufacture synthetic human insulin.

Nowadays, two groups of injected insulin are available: synthetic human insulin and analog insulin. Within these two groups of insulin, there are different types that have varying characteristics regarding when they start to work, when they peak, and how long they last.

Hopefully, your eyes haven’t started to glaze over yet, because there is plenty more information to cover about insulin. It may seem like a lot to digest at first, but you’ll soon get the hang of it. Remember: Your healthcare team is your best source for questions about insulin. No one is going to just give you a needle and a bottle of insulin and say, “Good luck.”

Instead, you’ll come up with an insulin plan — with the help of your healthcare provider, of course — for your type(s) of insulin, including when, how much, and how often to use insulin. This section is meant to be a primer so you know the scope of options available.

The table lists the commonly used types of insulin.

Human insulin

Synthetic human insulin is manufactured to be the same chemical structure as the insulin that your body naturally produces. However, its action is not the same as your body’s insulin because it clumps up when you inject it under the skin and it takes longer to absorb.

There are three types of human insulin:

• Short-acting human insulin (also called regular insulin) starts to work in 30 minutes, peaks at 2–3 hours, and lasts for 5–8 hours.
• Intermediate-acting insulin (also called NPH) starts to work in 2–4 hours, peaks at 4–10 hours, and lasts for 10–16 hours.
• Premixed combinations of short- and intermediate-acting insulin are also available.

How is human insulin made? Scientists put the human gene for insulin into bacteria or yeast, causing them to churn out insulin. The insulin is then extracted and purified. Voilá! It’s human insulin, without the humans (or perhaps a little help from humans).

Analog insulin

Analog insulin is manufactured to be similar to human insulin, but it has certain more desirable traits such as working more quickly or more slowly. Analog insulin is newer than human insulin — and it’s also more expensive.

There are three types of analog insulin:

• Fast-acting insulin starts to work in 15 minutes, peaks in 1–2 hours, and lasts for 3–5 hours.
• Long-acting insulin starts to work in 1–2 hours and can last up to 24 hours.
• Premixed analog insulin starts to work in 5–15 minutes and lasts up to 24 hours.

Whether you take human or analog insulin depends on many factors such as cost (in general, human insulin is cheaper), insurance coverage, convenience (analogs can provide more flexibility), and your blood glucose goals.

Inhaled insulin

Afrezza is the only FDA-approved inhaled insulin. Adults without chronic lung problems may be eligible to use Afrezza. You use an inhaler to breathe in Afrezza during mealtimes. It’s a fast-acting insulin that starts working within 15 minutes, peaks at about 1 hour, and last for 3 hours.