Semaglutide

Key points

• Semaglutide is a GLP-1 receptor agonist: a medicine that copies a gut hormone to lower appetite and blood sugar.
• It is licensed in the UK as Wegovy for weight management and as Ozempic for type 2 diabetes. Rybelsus is an oral form, licensed for diabetes.
• It is a prescription only medicine, so a registered prescriber must assess you first. A pharmacy cannot supply it from an online questionnaire alone.
• Wegovy and Ozempic are given as a once weekly injection under the skin, with the dose raised in steps.
• It is available on the NHS for some people under NICE criteria, and privately through CQC registered clinics and GPhC registered pharmacies.

Quick facts

UK status

Licensed prescription only medicine

Licensed as

Wegovy (weight management), Ozempic (diabetes), Rybelsus (oral, diabetes)

Class

GLP-1 receptor agonist

Half life

About 1 week, so it is given once weekly

Given as

Once weekly injection under the skin (Wegovy, Ozempic)

Legal supply

NHS services, CQC registered clinics, GPhC registered pharmacies

Dosing: the licensed step up

Wegovy for weight management is started low and raised in steps, usually every 4 weeks, to reduce stomach side effects, reaching a 2.4 mg maintenance dose. The schedule below is the licensed step up used in the trials and the product information. Ozempic for diabetes uses lower doses.

This is the licensed schedule, not a dosing recommendation. Your prescriber sets your dose and may move more slowly if you have side effects. Never change the dose yourself.

Put your own dates on it: Wegovy dose schedule →

How it works

Semaglutide copies the action of GLP-1, a hormone the gut releases after eating. It signals to the brain that you are full, slows how quickly the stomach empties, and helps the pancreas release insulin when blood sugar is high. Together these effects lower appetite and food intake, which is why the same molecule is used for both weight management and type 2 diabetes.

What the evidence shows

Semaglutide has been studied in large clinical trials. In the STEP programme for weight management, people on the weight management dose alongside diet and activity support lost much more weight on average than those on a placebo, around 15% of body weight over about 68 weeks. In the SUSTAIN programme for type 2 diabetes it lowered blood sugar and supported weight loss. The SELECT trial reported fewer heart attacks and strokes in people living with overweight or obesity who already had heart disease.

What it does not settle

• How much weight people keep off after stopping. Studies suggest much of it returns once treatment ends.
• Safety over many years is still being followed up.
• Results vary widely between individuals, and every trial pairs the medicine with diet and activity support.

Side effects

Common

• Nausea, vomiting, diarrhoea, constipation and stomach discomfort, most often while the dose is going up. These usually ease as the body adjusts.
• Headache, tiredness and dizziness.

Less common but serious

• Pancreatitis is rare but serious. Seek urgent medical help for severe, lasting stomach pain, especially with vomiting.
• Gallbladder problems, dehydration, and low blood sugar when it is combined with certain diabetes medicines.

Report any suspected side effect through the MHRA Yellow Card scheme.

UK legal status and access

Semaglutide is a licensed prescription only medicine, so there is a legal, regulated supply in the UK. You can be assessed on the NHS where you meet the NICE criteria, which differ by nation, or privately through a CQC registered clinic or a GPhC registered pharmacy. Choosing a provider that is registered with the GPhC or CQC helps you avoid fake or unsafe products.

UK approvals

• Sep 2023Wegovy injection became available in the UK for weight management, following NICE approval.
• Jul 2024The MHRA approved a cardiovascular risk reduction indication for Wegovy.
• Jun 2026An oral Wegovy tablet was approved for weight management, the first GLP-1 weight loss tablet in the UK.

Common questions