Insulin is a pancreas-produced hormone that has several important functions in the human body, in particular the control of blood sugar and the prevention of hyperglycaemia. It not only regulates the way the body uses and stores glucose and fat but also affects several other areas of the body, including lipid synthesis and the regulation of enzyme activity.

Insulin and blood sugar

Insulin helps control blood sugar levels by signalling the liver, muscle and fat cells to take up glucose from the blood. It therefore helps cells to take up glucose for use as an energy source. If the body has enough energy, insulin signals the liver to take up glucose and store it as glycogen. The liver can store up to about 5% of its mass as glycogen. Some cells in the body can take glucose from the blood without insulin, but most cells require the presence of insulin. In addition to its role in regulating blood sugar, insulin is also involved in the body's use of fat. When the liver has used up its glycogen capacity, insulin signals the fat cells to take up glucose and store it as triglycerides. More risk factors for diabetes can be found in this link on

Insulin and type 1 diabetes

In type 1 diabetes, the body produces insufficient insulin to regulate blood sugar levels. Without insulin, many of the body's cells cannot absorb glucose from the blood which leads to the body using other sources of energy. Ketones are then produced by the liver as an alternative energy source. However, high levels of ketones can lead to a dangerous condition called ketoacidosis. People with type 1 diabetes will need to inject insulin to compensate for their body's lack of insulin.

Insulin and type 2 diabetes

Type 2 diabetes is characterised by the body not responding effectively to insulin. This is called insulin resistance. As a result, the body is less able to absorb glucose from the blood. In the early stages of type 2 diabetes, the body responds by producing more insulin than it would normally need. In addition, while type 2 diabetes develops over some years, the extra demands placed on the pancreas to produce insulin can lead to the loss of insulin-producing cells as these can wear out. Depending on their level of insulin resistance, people with type 2 diabetes may also need insulin injections to manage their blood glucose levels.