GLP-1 medicines for type 2 diabetes: how they work and who can have them

Glucagon-like peptide-1 (GLP-1) is a hormone made in the gut and released after eating. GLP-1 receptor agonists mimic its action and can be prescribed to lower blood sugar levels in people with type 2 diabetes, to support weight loss, or to reduce the risk of major cardiovascular events in people with cardiovascular disease and obesity or overweight, according to Diabetes UK.

They work by increasing levels of incretin hormones, which help the body produce more insulin when needed and lower blood sugar. They also slow how quickly food is digested, make you full for longer and can reduce appetite, so many people lose weight. Although most are injections, they are different medicines from insulin.

Diabetes UK lists the following examples prescribed on the NHS, noting that newer brands are continually being developed.

• Semaglutide for type 2 diabetes: Ozempic, a once-weekly injection, and Rybelsus, a once-daily tablet. Wegovy is the brand used for weight management.

• Dulaglutide (Trulicity): a once-weekly injection.

• Liraglutide for type 2 diabetes: Diavic and Zegluxen, given once a day. Saxenda, Biolide and Nevolat are used for weight management.

• Tirzepatide (Mounjaro): a dual GLP-1 and GIP receptor agonist given once a week, used for type 2 diabetes or weight management.

The NHS says that if you need medicine for type 2 diabetes and have no other serious conditions you will usually be offered a combination of metformin and an SGLT2 inhibitor. If you have a history of heart disease you may also be offered a GLP-1 agonist, usually by injection once a week, and if you also live with obesity you may be offered one if other treatments cannot lower your blood sugar.

NICE guideline NG28, as summarised in NICE guidance published in 2026, says to offer subcutaneous semaglutide (Ozempic) up to 1 mg once a week as initial treatment with metformin and an SGLT-2 inhibitor for adults with type 2 diabetes and atherosclerotic cardiovascular disease, and to consider a GLP-1 receptor agonist or tirzepatide for adults with early-onset type 2 diabetes. For adults with type 2 diabetes and obesity (BMI 30 or more, with lower thresholds for some ethnic backgrounds), it says to consider adding a GLP-1 receptor agonist or tirzepatide after at least 3 months of metformin and an SGLT-2 inhibitor to help reach the glycaemic target.

Adults aged 18 and over can be prescribed GLP-1 medicines for type 2 diabetes. Dulaglutide and liraglutide are licensed for children and young people aged 10 and over with type 2 diabetes. Scotland may use SIGN guidance rather than NICE.

NICE says to stop a GLP-1 receptor agonist or tirzepatide if the person becomes underweight (BMI under 18.5), and to stop tirzepatide if it does not help the person reach their individualised glycaemic target. A GLP-1 receptor agonist taken for glycaemic benefit alone should be stopped if it does not help reach the target. Prescribing should follow an individual assessment of the treatment plan, diet and activity, side effect risk, dose and preferences.

Medicines can be paused around surgery or illness. The NHS advises asking for an urgent GP appointment or help from NHS 111 if you are taking diabetes medicine and have vomiting, diarrhoea or a very high temperature, because you may be told to stop temporarily. Do not stop unless a healthcare professional tells you to.

Common side effects are nausea, vomiting, constipation and diarrhoea. On their own GLP-1 medicines do not usually cause hypoglycaemia, but it can happen with insulin or a sulphonylurea, so those doses may be reduced. If insulin is reduced too quickly with a GLP-1, high blood sugar and an increased risk of diabetic ketoacidosis can occur.

Diabetes UK also lists a risk of worsening diabetic retinopathy with semaglutide in people who use insulin, and very rare reports of non-arteritic anterior ischaemic optic neuropathy (NAION) with sudden vision loss, which needs urgent medical advice. Acute pancreatitis is uncommon but can be serious. Its main symptom is severe pain in the stomach that radiates to the back, sometimes with vomiting, fever, jaundice or a fast heartbeat, and requires urgent medical help.

Regulators have investigated reports of suicidal thoughts. Diabetes UK says initial investigations found no evidence that these medicines cause suicidal thoughts or actions, but a small risk could not be completely ruled out and monitoring continues. People taking a GLP-1 should contact their team straight away about sudden changes in mood or new or worsening thoughts. Side effects can be reported to the Yellow Card Scheme.

Diabetes UK says a GLP-1 may not be suitable if you have severe digestive problems, severe liver disease, a history of pancreatitis, or kidney disease depending on stage, and that you should not take it if you are pregnant or breastfeeding, so people planning a pregnancy should speak to a healthcare professional. It will usually be stopped if diabetic ketoacidosis develops. GLP-1s are not licensed for type 1 diabetes and are not a replacement for insulin.

On the NHS, GLP-1 medicines for type 2 diabetes are prescribed through the GP or diabetes team as part of a wider plan including lifestyle changes, structured education and regular checks such as HbA1c every 3 to 6 months. Diabetes UK notes guidance has been produced for pharmacists providing private prescriptions, but a prescription should follow an individual assessment of your full medical history, so tell any private prescriber about all conditions and medicines, and keep your diabetes team informed.