What types of insulin are there?
As you might already realise, there are quite a few different types of insulin that can be used by people with type 1 diabetes, and they all have different actions. This is good as your diabetes team can choose the best to fit into your lifestyle. This is to try and keep your life as near to normal and how it was before you were diagnosed. Here is a document and also a chart that shows the main types of insulin which are explained below, but also shows you a daily graph so you can see how long they work in your body.
What are you taking?
1. Fast-Acting Analogue insulin
These insulins are designed to inject with carbs. So when you eat food containing carbs, you need insulin to move the glucose in your blood into the cells to use for energy. So this insulin needs to work fast to do this. There are 3 types called Apidra, Humalog or Novorapid. When injected and absorbed into the bloodstream, fast-acting analogue insulin starts to lower the blood glucose within 15 minutes. The peak time action is 1 – 2 hours after injection and can work for up to 5 hours. This insulin tries to copy the time food is digested, so before you eat you should inject your insulin dose and some people may inject and wait around 15 minutes before eating. Some people may be told to inject after food if the type of carbs are slow acting and take a while to be digested, like pasta for an example. Ask your diabetes team what you should do if you aren’t sure.
2. Soluble or Quick-Acting insulin
These insulins are a bit older and were used before fast-acting analogue insulin was around. They are Humulin S or Actrapid. They do work a bit longer and you usually need to inject them about 20 minutes before eating. When injected and absorbed into the bloodstream, insulin starts to work after 30 minutes. The peak time action is 2-3 hours after injection and can work for up to 6 hours. Sometimes people need to have a mid-morning and mid-afternoon snack as they can be a risk of having hypos as the insulin works for longer.
3. Long-Acting Analogue insulin
This insulin looks after your blood glucose levels when you aren’t eating carbs. You need it for your body to provide a constant supply of glucose to use as energy in the cells for daily maintenance and giving your organs glucose. There are two types called Lantus (Glargine) and Levemir (Detemir). These insulins work at a stable rate and have no peak time action. They start to work after around 1 hour after injection, and can last for 18-24 hours. You would usually take these insulins at the same time everyday and don’t usually have to adjust the dose often. You don’t need to eat carbs when you inject this as it is not used to look after carbs you have eaten.
4. Isophane insulin
This is an older version of long-acting insulin analogue insulin. They are called Humulin I or Insulatard. When injected and absorbed into the bloodstream, the insulin starts to work after 2 hours. The peak time action is 4-6 hours after injection and can work for up to 8-12 hours. Often people take this insulin twice a day.
5. Pre-Mixed insulin
The insulin types are: Humulin M3, Humalog mix 25 or 50, Hypurin Porcine 30/70, Mixtard 30, Novomix 30. Pre-mixed insulin contains either quick or fast-acting analogue insulin with isophane and is already mixed together in a vial. They are usually given twice a day before breakfast and evening meal. They start to work around 10-20 minutes after injection and last around 8-12 hours. The peak time is around 2-4 hours.
Next, we’ll talk about the different ways you can use these insulins.