Insulin is a hormone made in your pancreas, which is a gland behind the stomach. It helps your body use glucose (sugar) for energy.
When your pancreas is working properly it makes small amounts of insulin all the time and releases more insulin when your blood glucose levels increase after eating. When you have diabetes, your body does not make enough insulin or the insulin it makes does not work properly.
Everyone with type 1 diabetes, and some people with type 2 diabetes or gestational diabetes, needs to take insulin to help manage their blood glucose levels. This reduces the chances of getting the symptoms of high blood glucose (hyperglycaemia) and serious long-term problems that can damage the heart, kidneys, eyes, nerves and feet.
Long-acting insulin is a type of insulin that you inject once or twice a day. It works throughout the day and night to provide you with low levels of insulin all the time. Long-acting insulin is sometimes also known as basal insulin.
You may also need to use a rapid-acting insulin or short-acting insulin before meals to stop your blood glucose from going too high when you eat carbohydrates. Some people may take long-acting insulin along with other diabetes medicines to manage their blood glucose levels.
Long-acting insulin is available on prescription only. It comes as cartridges that you use in a reusable insulin pen, pre-filled pens, and a solution in a vial (a small bottle) for injecting.
Long-acting insulin types, brands and pens
There are 3 different types of long-acting insulin:
- insulin detemir (Levemir)
- insulin glargine (Abasaglar, Lantus, Semglee and Toujeo)
- insulin degludec (Tresiba)
They come in different brands and are used with different types of insulin pen, but they all work in a similar way.
Insulin detemir is usually taken twice a day. Insulin glargine and insulin degludec last for longer and are usually taken once a day.
Key facts
- Long-acting insulin starts to work after 30 minutes to 4 hours, depending on the type. It usually lasts for 16 to 24 hours, depending on the type and your dose. You'll usually take it once or twice a day.
- Your doctor or diabetes nurse will tell you how much long-acting insulin to take.
- Insulin treats the symptoms of diabetes by lowering your blood glucose. But it can sometimes cause your blood glucose to go too low. This is known as hypoglycaemia, or hypos. Make sure you know the symptoms of a hypo, and always carry a source of glucose with you, such as sugary sweets, in case you need to treat a hypo.
- It's a good idea to carry medical identification such as an insulin safety card or insulin passport – a small card with up-to-date details of the type of insulin you use, and what to do in an emergency.
- If you have diabetes, you're entitled to free prescriptions for all your medicines, not just your insulin.