Independent UK Compound Guide
Semaglutide
Independent information on how Semaglutide works, what clinical research shows, common side effects, injection frequency, cost and what may happen when treatment stops.
Slim Shots is an independent educational resource. Semaglutide is a prescription-only medicine in the UK. This page does not replace advice from a doctor, pharmacist or other qualified healthcare professional.
Semaglutide Explained
What Is Semaglutide?
Semaglutide is a medicine in a group called GLP-1 receptor agonists. It is the active ingredient in branded medicines including Wegovy® and Ozempic®.
GLP-1 is a hormone the body naturally releases after eating. Semaglutide acts on GLP-1 receptors involved in appetite, fullness and blood-glucose regulation. Depending on the product and clinical circumstances, Semaglutide may be prescribed for type 2 diabetes or weight management.
In the UK, licensed Semaglutide medicines are prescription-only. Whether treatment is suitable depends on an individual's health, medical history, current medicines and treatment goals.
Mechanism of Action
How Does Semaglutide Work?
Semaglutide works through the GLP-1 pathway. Its effects can include changes to appetite, fullness and blood-glucose regulation.
Appetite Regulation
GLP-1 receptor activity can reduce hunger and help some people feel satisfied with less food.
Feeling Full for Longer
Semaglutide can slow gastric emptying. This may contribute to a longer-lasting sensation of fullness after eating.
Blood-Glucose Effects
Semaglutide also affects insulin and glucagon in a glucose-dependent way, which is relevant to its use in type 2 diabetes treatment.
Product Imagery
Semaglutide Vial Formats
Semaglutide products can differ by dose, presentation, delivery method and prescribing instructions. Always follow the information supplied with the specific product prescribed or provided to you.
Semaglutide
5 mg vial
Semaglutide
10 mg vial
Clinical Research
How Much Weight Can You Lose With Semaglutide?
Weight-loss outcomes vary significantly between individuals. Factors can include baseline weight, treatment duration, dose, dietary changes, physical activity, other health conditions and whether treatment is tolerated.
In the STEP 1 clinical trial, adults with overweight or obesity who received once-weekly Semaglutide 2.4 mg plus lifestyle intervention had an average body-weight reduction of approximately 14.9% over 68 weeks.
A clinical-trial average is not a guarantee of an individual outcome. A qualified prescriber can assess suitability and monitor progress.
STEP 1 Clinical Trial
14.9%
Average body-weight reduction over 68 weeks
Reported in adults receiving Semaglutide 2.4 mg alongside lifestyle intervention. Individual results can vary substantially.
Product Context
Semaglutide, Wegovy® and Ozempic®
Semaglutide is the active ingredient in both Wegovy® and Ozempic®, but these are different branded products with different licensed uses, dose schedules, delivery devices and prescribing arrangements.
| Topic | Semaglutide | Important Context |
|---|---|---|
| Active ingredient | Semaglutide | Semaglutide is the active ingredient in branded medicines including Wegovy® and Ozempic®. |
| Licensed uses | Depend on the specific medicine and prescribing decision. | Wegovy® and Ozempic® are not interchangeable simply because they contain the same active ingredient. |
| Dosing and delivery | Product-specific. | Follow the instructions from a clinician, pharmacist and the product information for the exact medicine supplied. |
| Suitability | Assessed individually. | A qualified healthcare professional should consider medical history, medicines, treatment goals and potential risks. |
Semaglutide FAQs
Frequently Asked Questions About Semaglutide
Clear answers to common Semaglutide questions, including cost, side effects, injections, branded medicines and stopping treatment.
What is Semaglutide?
Semaglutide is a GLP-1 receptor agonist medicine. It is the active ingredient used in branded medicines including Wegovy® and Ozempic®. In the UK, licensed Semaglutide medicines are prescription-only.
How does Semaglutide work for weight loss?
Semaglutide mimics GLP-1, a naturally occurring hormone. It can reduce appetite, increase feelings of fullness and slow gastric emptying. For eligible people, it may be used alongside nutrition, activity and behavioural changes as part of a broader treatment plan.
How much weight can you lose with Semaglutide?
Results vary. In the STEP 1 clinical trial, people receiving Semaglutide 2.4 mg with lifestyle intervention had an average body-weight reduction of approximately 14.9% after 68 weeks. Individual outcomes can be higher or lower and are not guaranteed.
How much does Semaglutide cost in the UK?
Private costs vary by provider, prescribed product, dose, consultation arrangements and monitoring. NHS availability depends on eligibility criteria and local pathways. Check current availability, price and clinical suitability directly with a regulated prescriber or pharmacy.
What are the common side effects of Semaglutide?
Common side effects can include nausea, vomiting, diarrhoea, constipation, stomach pain, headache and tiredness. Stomach-related side effects can be more noticeable when treatment starts or after a dose change. Speak to a prescriber or pharmacist if side effects are severe, persistent or concerning.
Are there serious Semaglutide side effects to be aware of?
Serious side effects are less common but can occur. Seek urgent medical advice for severe or persistent abdominal pain, signs of a severe allergic reaction, dehydration caused by repeated vomiting or diarrhoea, or sudden changes in vision. Tell your prescriber about your medical history and any medicines you use before treatment.
How often is Semaglutide injected?
Injectable Semaglutide is generally administered once weekly. However, the exact instructions depend on the specific prescribed product. A clinician or pharmacist should explain the correct injection technique, injection site and site rotation.
Is Semaglutide the same as Ozempic® and Wegovy®?
Semaglutide is the active ingredient in both Ozempic® and Wegovy®. They are different branded medicines with different licensed uses, dose schedules, delivery devices and prescribing arrangements. A prescriber can advise which product, if any, is appropriate.
What happens when you stop taking Semaglutide?
The appetite and fullness effects of Semaglutide reduce after treatment stops. Weight regain can occur, particularly without continued nutrition, activity and behavioural support. Speak to your prescriber before stopping, especially if Semaglutide is being used for type 2 diabetes.
Do you need a prescription for Semaglutide in the UK?
Yes. Licensed Semaglutide medicines are prescription-only in the UK. Appropriate assessment, prescribing and monitoring should be provided by a qualified healthcare professional.
Safety and Suitability
Semaglutide Is Not Suitable for Everyone
Before prescribing Semaglutide, a healthcare professional should consider medical history, existing conditions, current medicines, previous side effects and pregnancy plans.
Only use medicines obtained through an appropriate regulated route. If you experience a suspected side effect, speak to a healthcare professional. In the UK, suspected side effects can also be reported through the MHRA Yellow Card scheme.
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Semaglutide Information Sources
- Clinical weight-loss evidence: Wilding JPH et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity, STEP 1 trial.
- UK medicine information: NHS Semaglutide medicine guidance, including licensed uses and product information.
- Side effects and safety information: UK Medicines and Healthcare products Regulatory Agency and the British National Formulary.
Semaglutide Information
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