Types Of Insulin

Insulin is a vital hormone that is made by both humans and animals alike. When insulin was first recognised as a treatment for diabetes, it was harvested from animal sources such as cows and pigs. This insulin was then used by patients to replace the insulin their bodies could no longer make. This type of insulin is still used in developing countries, however in the UK, it is now synthetically made.

There are a number of different types of insulin that are available today. These include:

Regular Insulin
Rapid Acting Insulin
Intermediate Insulin
Prolonged Acting Insulin
Combination Insulin

Regular Insulin

Regular insulin is used approximately half an hour before eating and can last up to four hours after a meal. Sometimes this can lead to hypoglycaemic events after eating.

Rapid Acting Insulin

Rapid acting insulin is usually used before meals that are high in carbohydrates. This helps to prevent hypoglycaemia that can occur after eating. It is absorbed into the circulation extremely rapidly, usually within 5-10 minutes. It is also removed from the blood very quickly. Another advantage to this type of insulin is that it can be given after eating, due to it being absorbed very rapidly. Examples include insulin aspart (Novalog) and insulin lispro (Humalog). This type of insulin has been used to help decrease symptoms of night time hypoglycaemia.

Intermediate Insulin

Intermediate insulin is longer acting than both the regular and rapid acting insulin. It is usually made as a mixture of two types of insulin. The first type is called NPH (neutral protamine Hagedorn) which is usually mixed with a soluble insulin to make a form that acts both quickly and over longer periods. It starts acting within two hours and has its greatest effect 12 hours post injection. There are other forms of intermediate insulin that can be mixed with the soluble type prior to use, the main one is zinc insulin (Lente), which acts over the same time scale as NPH.

Prolonged Acting Insulin

Prolonged acting insulin continues to work up to 24 hours after injection It is able to stay in the muscle it has been injected into then dissolve slowly back into the blood. The most widely used prolonged acting insulin is insulin glargine (Lantus). It carries a lower risk of hypoglycaemia than the other types of insulin.

Combination Insulin

Combination insulin is a relatively new method of combining the rapid and prolonged types of the hormone to give the best clinical outcome possible. It allows you to have fewer injections over the course of the day whilst still maintaining good control of your blood sugar levels. The most common mixtures are NPH added to soluble insulin.