On this page:
- What is semaglutide?
- How does semaglutide work?
- How many types of semaglutide are there?
- Who can take semaglutide?
- Your prescription
- Semaglutide side effects
- More information and support
What is semaglutide?
Semaglutide can be prescribed to lower blood sugar levels in people with type 2 diabetes. It can also be prescribed to support people with weight loss or to reduce the risk of major cardiovascular events such as heart attack or stroke in people living with cardiovascular disease (CVD) and obesity or overweight.
Semaglutide belongs to a group of drugs called GLP-1 receptor agonists (GLP-1 RAs or GLP-1s) – they can also be known as GLP-1 analogues, GLP-1 agonists or incretin mimetics.
How does semaglutide work?
Glucagon-like peptide GLP-1 is a naturally occurring hormone in the gut and is released after eating. Semaglutide is a medication that mimics the action of natural GLP-1.
It works by helping your body to produce more insulin when needed. It also reduces the amount of glucose, or sugar, produced by the liver, and slows down how quickly food is digested. This all helps to lower blood sugar levels and HbA1c.
Semaglutide can also lead to weight loss. This is because it slows down how quickly food is digested. This means it can help you stay full for longer, which can lead to weight loss.
How many types of semaglutide are there?
Semaglutide is available under three different brand names:
- Ozempic – a type 2 diabetes medication that you inject, which is prescribed to manage blood glucose levels. It should only be prescribed to people with type 2 diabetes.
- Rybelsus – a drug that comes as a tablet that you swallow, which can be used to treat type 2 diabetes.
- Wegovy – a drug that you inject, which is available on the NHS to support weight management.
Who can take semaglutide?
Type 2 diabetes
Adults aged 18 and over with type 2 diabetes can take semaglutide.
New guidelines from the National Institute for Health and Care Excellence, or NICE for short, recommend earlier use of GLP-1s for some groups of people. You’re more likely to be offered a GLP-1 such as semaglutide if you’re an adult with type 2 diabetes and:
- You were diagnosed before the age of 40
- Have cardiovascular disease such as heart disease or stroke
- Are living with obesity.
Your healthcare team will discuss your options to decide if this treatment is right for you based on your individual needs and circumstances. If you think that you would benefit from taking semaglutide for diabetes management, speak with your healthcare team so that you can make an informed decision together about your treatment.
NICE guidelines are used in England and Wales and tend to be endorsed and adopted in Northern Ireland. If you live in Scotland, care may be based on SIGN guidelines. Please speak to your healthcare team if you have any questions or concerns about your treatment.
Weight management
Adults aged 18 and over can take semaglutide for weight management alongside a reduced-calorie diet and physical activity.
NICE guidelines recommend Wegovy for adults who have a body mass index (BMI) of 35kg/m² and over, and at least one weight-related health condition, such as prediabetes or type 2 diabetes or a BMI of 30kg/m² to 34.9kg/m² and meet the criteria for referral to specialist overweight and obesity management services.
NICE recommends – due to their risk from obesity-related health problems at a lower BMI – that people from Black African, African-Caribbean, Asian, South Asian, Chinese, and Middle Eastern backgrounds receive Wegovy at a lower BMI.
Cardiovascular disease
Wegovy might be prescribed to adults living with cardiovascular disease and obesity or overweight to reduce the risk of major cardiovascular events such as heart attack or stroke. This includes people living with or without type 2 diabetes.
Can children take semaglutide?
Wegovy is licensed for weight management in children and young people aged 12 and over who live with obesity and weigh over 60kg, it’s usually only prescribed in specialist weight management clinics by specialist doctors.
Who can’t take semaglutide?
Some medications might not be suitable for some people, which might be because of medical conditions or other reasons. The list below shows some of the reasons semaglutide might not be a suitable treatment for you:
- If you have end-stage kidney disease, you might not be able to take semaglutide;
- If you have severe liver disease, you might not be able to take semaglutide;
- You might need to temporarily stop semaglutide if you’re going to have an operation;
- If you have severe heart failure, semaglutide might not be suitable for you;
- If you’ve had pancreatitis before, semaglutide might not be suitable for you. Your doctor will tell you to stop taking this medication if you have pancreatitis;
- Your doctor will tell you to stop taking semaglutide if you develop diabetic ketoacidosis, also called DKA;
- You should not take semaglutide during pregnancy. It should not be used if you are breastfeeding. If you are planning a pregnancy, it’s very important to speak to a healthcare professional if you are using this medication.
The patient information leaflet that comes with the medication will have an up to date list of warnings and precautions. When you start a new medication, always check with your healthcare team that it’s suitable for you to take. You can discuss any other medical conditions you have and any other medications you are taking.
Your prescription
Your healthcare team should explain your prescription to you, but it's important to make sure you ask if you don't feel you know enough.
And make sure you talk to your GP or your diabetes team if you struggle to take your medication. They might be able to help by giving you a different dose.
In England, if you need to take any medication to manage your diabetes, your prescriptions will be free. Ask your healthcare team about a prescription exemption certificate if you don't have one, to make sure you don't get charged for your medication. Prescriptions are already free for everybody in the rest of the UK, so you shouldn't pay for your medication.
Semaglutide side effects
Common side effects of semaglutide can include:
- feeling sick (nausea)
- being sick (vomiting)
- constipation
- diarrhoea
- risk of low blood sugar
- risk of worsening retinopathy.
Risk of low blood sugar
Our pages on the different brands of semaglutide, Ozempic, Wegovy and Rybelsus, have further information about the risk of blood sugar becoming too low, also called hypoglycaemia or hypos, when taking these medications.
Hypos are more likely to happen when you take semaglutide with other diabetes medications such as insulin or a sulphonylurea. Speak to your healthcare team if you aren’t sure if the diabetes medication you take increases your risk of hypos.
Your healthcare team may advise reducing the dose of your sulphonylurea or insulin medicine when you start taking semaglutide to reduce the risk of hypos.
Risk of high blood sugar
If you take semaglutide with insulin and your insulin dose is reduced too quickly, this can cause high blood sugar, also known as hyperglycaemia, and there is an increased risk of DKA. Your health care team should discuss with you the signs and symptoms of DKA.
Risk of worsening retinopathy
If you have diabetic eye disease, known as diabetic retinopathy, and you’re taking insulin, then your retinopathy could get worse when you start using semaglutide, and this might need treatment.
Tell your doctor if you have diabetic eye disease or if you experience eye problems during treatment with semaglutide.
Risk of Non-arteritic anterior ischemic optic neuropathy (NAION)
NAION is a condition that affects the optic nerve in the eye. NAION happens when blood flow to the optic nerve is reduced. This can cause sudden loss of vision, typically in one eye. It’s often described as a blurring or cloudiness of vision. Semaglutide (Ozempic, Rybelsus, Wegovy) has been associated with very rare reports of NAION. If you notice a sudden change in your eyesight such as sudden vision loss or your eyesight gets worse very quickly in one or both of your eyes during treatment with semaglutide, seek urgent medical advice.
These are not all the side effects. You will find a full list of known side effects in the Patient Information Leaflet. This comes in the medication box.
Like all medications, semaglutide can cause side effects. But when side effects are listed as common in the Patient Information Leaflet, it doesn’t mean that everyone who takes the medication will get them. Read more about GLP-1 agonist side effects.
The information about side effects is based on the likelihood of people having them. For example, if a side effect is very common, then it can affect more than one in ten people, and if a side effect is very rare, then it affects fewer than one in 10,000 people.
Because medicines can affect people differently, your healthcare team will speak to you about what’s best for you and discuss any side effects.
It’s also important that you take individual advice from your healthcare team before starting GLP-1 agonist treatment and report any side effects to your healthcare professionals if you experience any.
You can also report these side effects to the Yellow Card Scheme, which is the government system used for recording adverse effects and incidents with medicines in the UK.
More information and support
If you're worried about your medication, struggling with side effects, or want to know if it's right for you, speak with your healthcare team.
Still have more questions? Or is there anything you're not sure about semaglutide after reading this page? Contact our helpline on 0345 123 2399.
You can visit the NHS website for more information on semaglutide.
