You'll usually take a dose of long-acting insulin once or twice a day. If you take it once a day, try to stick to the same time each day. If you take it twice a day, take the doses 12 hours apart and try to stick to the same times each day. either 100 or 200 units of insulin per 1ml. Make sure you know what strength of insulin you're taking.
You'll usually take a dose of long-acting insulin once or twice a day. If you take it once a day, try to stick to the same time each day. If you take it twice a day, take the doses 12 hours apart and try to stick to the same times each day.
Your doctor or diabetes nurse will tell you how many units of insulin you'll need to take.
The dose of long-acting insulin you need depends on:
You may need to change your dose:
It's a good idea to keep a record of the amount of insulin units you inject if possible.
Testing your blood glucose regularly will help you and your diabetes healthcare team know if you're taking the right dose for you. Your doctor or diabetes nurse will explain how to do this.
Information:Most people take long-acting insulin using an insulin pen. The type of pen you'll use depends on which brand of insulin you've been prescribed. There are different types of pre-filled pens and reusable pens so check the instructions for the type of pen you're using.
If you use vials and syringes to inject instead of a pen, your diabetes nurse will show you how to do this.
When you start taking insulin your diabetes nurse will show you how to use your pen to inject. Always follow the instructions for your pen.
Using an insulin pen does not usually hurt. The needles are very small as you only inject a small amount into the layer of fat just under your skin.
It's important to vary the places you inject so that you're less likely to get fatty lumps under your skin (lipohypertrophy). Although these are usually harmless, they can mean that insulin is not always absorbed at the same speed when you inject into them. This can affect your blood glucose.
Information:It's important to always take the right amount of insulin. To avoid making any mistakes with your insulin dose:
Insulin pens are designed to stand up to a lot of wear and tear. But they can sometimes become faulty, and this can affect your blood glucose levels.
If you're concerned that your pen is not reliably giving the right dose of insulin, contact your doctor or diabetes nurse for advice.
If you have type 1 diabetes you'll need to take insulin for your whole life.
If you have type 2 diabetes you'll need to take insulin if other treatments for diabetes are not reducing your blood glucose enough. Once you start taking insulin it's likely that you'll need to take it for the rest of your life, provided it improves your blood glucose and you cope well with the treatment.
If you're taking insulin to treat gestational diabetes you can usually stop taking it once your baby is born, as the condition usually goes away after you give birth.
It's important to take insulin as recommended by your doctor or nurse. Speak to them if you have any problems with taking it.
When your blood glucose is well managed you're less likely to get the short-term symptoms of high blood glucose (hyperglycaemia) such as blurred vision, needing to pee more, tiredness and feeling very thirsty. You're also less likely to get serious long-term problems that can damage your heart, kidneys, eyes, nerves and feet.
Stopping insulin suddenly can lead to severe hyperglycaemia and a life-threatening condition called diabetic ketoacidosis.
If you have any concerns about your insulin treatment, talk to your diabetes specialist, doctor or diabetes nurse.
Taking too little insulin increases the risk of high blood sugar (hyperglycaemia) and long-term complications from diabetes.
If you forget to take your dose of long-acting insulin but remember within 2 hours of when it was due, it's usually OK to take your usual dose as soon as you remember. But be aware that the insulin will continue to work in your body later than it normally would and this might increase your risk of a hypo. Speak to your diabetes team if you're worried.
If you forget for longer than 2 hours and you're not sure what to do, speak to your diabetes team. Check your blood glucose before contacting them as this information will help them advise you.
Look out for any signs of high or low blood glucose levels, and check your blood glucose levels more often than usual for the next 24 hours. Contact your doctor or diabetes nurse if you're concerned.
Never take 2 doses to make up for a forgotten dose.
If you often forget doses, it may help to set an alarm to remind you. You could also ask your pharmacist for advice on other ways to help you remember to take your long-acting insulin.
Taking too much long-acting insulin can make your blood sugar go too low, causing hypoglycaemia (a hypo). You might also have a hypo if you:
Symptoms of low blood sugar include:
It's also possible for your blood sugar to go too low while you're asleep. If this happens, you may wake up at night feeling sweaty and confused, or you may feel tired or have a headache in the morning. Speak to your diabetes team if you think you might be having hypos at night.
These symptoms happen when your blood glucose falls below 4mmol/L.
If you get hypo symptoms, follow the instructions you've been given to treat a hypo:
Always carry glucose tablets or high sugar snacks with you in case you have a hypo.
Do not drive, cycle or use machinery if you've taken too much insulin, even if you do not have symptoms. If you have a hypo, do not drive for at least 45 minutes after you've recovered.
Try to make sure someone stays with you if you've taken too much insulin.
If you have very low blood glucose (a severe hypo) you may become drowsy or unconscious. Make sure your family or friends know what to do if this happens, including how to give a glucagon injection, and when to call 999 for an ambulance.
Find out more about side effects of long-acting insulin including severe hypos.
Page last reviewed: 7 July 2023
Next review due: 7 July 2026