Insulin is a hormone made in your pancreas. It helps your body use glucose (sugar) for energy.
In type 1 diabetes your pancreas no longer makes insulin, so you have to inject it to control your blood glucose levels.
There are different types of insulin, taken at different times.
Insulin taken once or twice a day
This is called long-acting, background or basal insulin.
It gives your body the insulin it needs whether you eat or not.
Basal insulin should keep your blood glucose stable overnight and between meals.
Insulin taken with food or drink
This is called fast-acting, mealtime or bolus insulin.
It helps reduce the rise in blood glucose caused by eating or drinking.
You usually take it before a meal, snack or drink with carbohydrates in it.
Diabetes UK has more information on treating diabetes with insulin.
Page last reviewed: 14 May 2018
Next review due: 14 May 2021