Types of insulin - Explained

In this article, we will explore the types of insulin and understand the basis for insulin classification.

Let us understand the function of insulin.

Insulin and its importance

Insulin is a hormone secreted by the beta cells of the pancreas to regulate blood glucose levels.

If insulin is deficient or the body is unable to respond to the insulin it leads to diabetes which requires insulin to be administered from external sources to manage hyperglycemia or high blood glucose levels.

Based on the onset time (how long it takes to start working) and the duration (how long it lasts) of insulin action, insulin is broadly classified into 5 types.

Rapid Acting Insulin
Short Acting Insulin
Intermediate Acting Insulin
Long-Acting Insulin
Mixture

Let us get familiar with the methods of insulin administration.

Methods of insulin administration

Why is insulin not administered orally?

When ingested, insulin reaches the GI tract and gets destroyed and digested in the acidic pH of the stomach by being acted upon by HCl.

Hence, insulin is not administered orally and can only be administered through

Intravenously or IV – less common method
Subcutaneous tissue – more common method

Over the years, insulin has been extracted from pigs and bovine which are not completely identical to human insulin. With advances in biotechnology, insulin that is identical to human insulin (humulin) could be developed synthetically for treating diabetic patients.

Classification of insulin

Type	Onset of action	Duration of action	Insulin under brand name
Rapid Acting Insulin	15 minutes	2 to 4 hours	Novolog or Insulin AspartHumalog or Insulin lisproApidra or insulin glulisine
Short Acting Insulin	30 minutes	3 to 6 hours	Novolin R or Insulin Regular
Intermediate Acting Insulin	1 to 2 hours	12 hours	Novolin N or NPHInsulin-Zn (with Zn suspension)
Long Acting Insulin	2 to 4 hours	24 hours	Levemir or Insulin detemirLantus, Basaglar or Insulin glargine
Mixture	Mixture Insulin is a combination of two or more than two types of insulin.The mixture can beRegular or Rapid acting mixture with 20-50% of rapid or regular insulin mixed with the other.Isophane or NPH with 50-80% of either component.Longer Acting Analog – a mixture of different long-acting insulin types.

Important points to remember:

Only in case of an emergency, Regular Insulin can be given Intravenously (IV)
Characteristics of Regular insulin which makes it the only insulin type-safe to be administered through the IV method.