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Insulin

What is insulin?

Insulin is a hormone that allows glucose to move from the bloodstream into the body’s cells, where it can be used for energy.

Read more in our fact sheet Insulin.

When you have type 1 diabetes

Your body either makes very little or no insulin at all. This is because the immune system destroys the insulin-producing cells in the pancreas. To make up for this lack of insulin, you will need to inject insulin several times a day, or infuse it continuously via an insulin pump.

When you have type 2 diabetes

Your pancreas can still make insulin but it either does not work properly or there is not enough of it. This causes your blood glucose levels to rise above the normal range.

Type 2 diabetes is managed through healthy eating and regular physical activity. You may also need glucose-lowering medications such as tablets. As type 2 diabetes progresses, you may also need injectable medications (insulin and non-insulin types) to help keep your blood glucose levels in the target range.

Read more in our fact sheet Concerns about starting insulin (for people with type 2 diabetes).

Read more about the role of insulin in the management of type 2 diabetes in our Starting insulin booklet.

Insulin during pregnancy for women with type 2 diabetes

Some women with type 2 diabetes may already be taking insulin before becoming pregnant. Other women may need to start taking insulin early during pregnancy to help manage their blood glucose levels. Most women with type 2 diabetes will need insulin at some stage during their pregnancy.

Your insulin requirements are likely to change constantly throughout your pregnancy, as different hormones take effect and your baby grows.

As pregnancy progresses, it is common to need more insulin. This is because the hormones made by the placenta interfere with the way your insulin normally works – as the pregnancy hormones rise, so does your need for insulin. It is common to adjust your insulin dose at least once a week in the second half of pregnancy.

Insulin requirements tend to continue rising until about 34 to 36 weeks, when they may plateau or start to fall a little. If you notice your insulin requirements fall significantly and rapidly in late pregnancy, this can be a sign of problems with the pregnancy–contact your specialist for advice immediately.

Read more in our booklet Having a healthy baby: a guide to planning and managing pregnancy for women with type 2 diabetes.

When you have gestational diabetes

Gestational diabetes is a type of diabetes that can occur during pregnancy. When you are pregnant, some of the hormones that the placenta produces make it more difficult for insulin to work properly. The pancreas then needs to produce extra insulin to keep blood glucose levels in the target range. If the pancreas is unable to produce enough insulin, blood glucose levels rise, and gestational diabetes develops. Gestational diabetes can be managed by following a healthy eating plan, regular physical activity and monitoring blood glucose levels. You may also need medication or insulin injections to help manage gestational diabetes.

Administering insulin

Currently, insulin can only be injected or infused. Insulin cannot be given in tablet form, as it would be destroyed in the stomach. This means that it would not be available to convert glucose into energy.

Insulin is injected or infused through the skin into the fatty tissue known as the subcutaneous layer. You do not inject or infuse it into muscle or directly into the blood. The absorption of insulin varies depending on the part of the body into which you inject or infuse it. The tummy (abdomen) absorbs insulin the fastest and is the site most people use, although others prefer to use the buttocks and thighs.

While it is essential to inject or infuse insulin in a slightly different spot within the one site, it is not advisable to change sites without first discussing it with your doctor or diabetes educator.

The range of devices make injecting or infusing insulin much easier than most people imagine. When starting insulin, your doctor and diabetes educator will help you adjust to the new routine and the task of giving insulin, as well as find the right dose for you to reduce your blood glucose levels to your target range.

Insulin can be injected by an insulin syringe, an insulin pen with a fine needle, or infused via an insulin pump. The method chosen is based on an individual’s needs.

Insulin syringes and insulin pens (pen needles) are currently the most common way of injecting insulin. Injection devices are made in different sizes, and the size used depends on the quantity of insulin being injected. To avoid under-dosing or overdosing, it is important you know how to measure the insulin dose in your device. Your diabetes educator can help you with this.

Many people find insulin pens easier to use than syringes. If you have difficulties with your sight or with arthritis, you may find an insulin pen easier to use.

An insulin pump is a small programmable device that holds a reservoir of insulin. The pump is programmed to infuse insulin into the body through thin plastic tubing known as the infusion set or “giving set”. The pump is worn outside the body, in a pouch or on your belt. The infusion set has a fine needle or flexible cannula that is inserted just below the skin, where it stays in place for two to three days.

Only fast-acting insulin is used in the pump. Whenever food is eaten the pump is programmed to deliver a surge of insulin into the body similar to the way the pancreas does in people without diabetes. Between meals, a small and steady rate of insulin is infused.

An insulin pump is not suitable for everyone. If you’re considering using one, you should discuss it first with your doctor or diabetes educator.

Read more in our fact sheet Insulin.

Types of insulin

When you take insulin, it acts to reduce the level of glucose in your blood. When glucose is at its lowest level, the effect of the insulin is said to have reached its ‘peak’. After this, the effect gradually wears off and blood glucose levels rise.

Your doctor or diabetes educator will work out with you what type of insulin is right for you.

Read more in our fact sheet Insulin.