What type of drug is semaglutide?
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What type of drug is semaglutide? Learn about this GLP-1 treatment and how it supports weight loss.
If you've ever wondered 'what type of drug is semaglutide?', you're in the right place.
Semaglutide is the active ingredient in Wegovy – a prescription-only medication used to support weight loss.
It's a GLP-1 receptor agonist (also called an 'incretin mimetic'). That means it mimics natural hormones in the body that help regulate appetite, digestion and blood sugar.
Keep reading to find out everything you need to know about this weight loss drug and how it could help you lose weight and keep it off.
What does 'GLP-1 receptor agonist' mean?
A GLP-1 receptor agonist is a medicine used to treat obesity and type 2 diabetes. It mimics the naturally occurring hormone GLP-1, which stands for 'glucagon-like peptide-1'.
This hormone plays an important role in regulating blood sugar, digestion and appetite. It increases insulin production in the body, which lowers blood sugar by moving glucose out of the bloodstream and into cells. At the same time, it reduces glucagon – a hormone that raises blood sugar by telling the liver to release stored glucose.
GLP-1 receptor agonists like Wegovy help:
- Make you feel full more quickly
- Curb cravings
- Slow how quickly food leaves the stomach
- Keep blood sugar levels more stable
This usually results in you naturally eating less and feeling more satisfied with smaller portions. If you take Wegovy as part of a
medical weight loss plan, there's no need to follow extreme food rules or meal replacements.
Is Wegovy the same as semaglutide?
Yes. Wegovy is the brand name for semaglutide when prescribed for weight loss.
How do I take Wegovy?
Wegovy is taken once a week by injection using a pre-filled injection pen. You start on a low dose, which increases gradually over time. This helps your body adjust and makes side effects less likely.
Is semaglutide effective for weight loss?
Yes. Semaglutide is one of the most effective weight loss drugs currently available.
In a large clinical trial, people using Wegovy lost an average of 15% of their body weight over 68 weeks.
This trial also showed that semaglutide works best alongside a healthy, balanced diet and regular exercise. No extreme restrictions or crash diets are needed.
How does semaglutide compare to other weight loss drugs?
Semaglutide is part of a wider group of medicines used for weight loss. They all work in similar was.
Mounjaro (tirzepatide)
Mounjaro is a newer injectable drug that mimics both GLP-1 and glucose-dependent insulinotropic polypeptide (GIP), another hormone involved in digestion. This combination makes it even more effective for weight loss than semaglutide alone.
In clinical trials, people using Mounjaro lost an average of 21% of their body weight over 72 weeks.² That's compared to 15% with Wegovy.
Tirzepatide is available in the UK on private prescription. It's also available to a limited number of people on the NHS.
Saxenda (liraglutide)
Saxenda is an older GLP-1 medication. It also helps you feel fuller and reduces appetite, but it needs to be taken daily as an injection. This daily dosing schedule can make it harder to stick to.
Saxenda is still prescribed when other options aren't suitable or available. However, it's being used less often.
Is there a tablet version of Wegovy?
Yes, semaglutide is also available as a tablet called 'Rybelsus'. It's approved for type 2 diabetes, not weight loss. At the time of writing, Rybelsus is not licensed in the UK for treating obesity.
What are the side effects of semaglutide?
Like all medications, semaglutide can cause side effects. Most are tolerable and get less severe as your body adjusts. Common side effects include:
- Nausea
- Constipation
- Diarrhoea
- Headaches
- Tiredness or low energy
Some people experience more serious side effects, but these are rare. This is one reason why semaglutide should always be prescribed by a medical professional who can assess your health and monitor your progress.
To learn more, read our guide to Wegovy side effects.
Why do people choose GLP-1 medications?
Many people find that GLP-1s like Wegovy help them lose weight in a way that feels manageable. You don't have to follow a restrictive diet plan – just a normal, healthy diet. With Wegovy, you simply feel less hungry and eat less with no need for meal replacements or drastic changes.
It can also help improve blood sugar levels, which is helpful if you're at risk of developing type 2 diabetes.
GLP-1 medications like Wegovy provide medical support that works alongside lifestyle changes. They give your body the help it needs to lose weight more effectively.
How SemaPen can help
SemaPen is part of Phoenix Health, the only provider of bariatric care trusted to provide NHS treatment. We prescribe both Wegovy (semaglutide) and Mounjaro (tirzepatide) as part of a fully supported, evidence-based programme.
You won't just receive the medication. You'll also get personalised care from obesity experts who understand the challenges of weight loss.
Our programmes include:
- A full medical consultation to check if either of the treatments are right for you
- A smart scale that sends data directly to your care team
- Regular check-ins with obesity experts through live chat
- A money-back guarantee if the treatment doesn't work*
If you're losing weight too slowly or quickly, one of our experts will step in and help you get back on track. And if you have questions or concerns, we're always on hand to support you.
Whether you're prescribed Wegovy or Mounjaro, we're here to help you get the best possible results safely.
Are you looking for expert support with Wegovy or Mounjaro? When you join the SemaPen programme, you're supported by real obesity specialists – not just pharmacists or GPs. Why not take our online consultation to see if our programmes are right for you?
Sources
1. Wilding, J.P.H. et al. (2021) "Once-weekly semaglutide in adults with overweight or obesity" The New England Journal of Medicine, 384(11) https://doi.org/10.1056/NEJMoa2032183
2. Jastreboff, A.M. et al. (2022) "Tirzepatide Once Weekly for the Treatment of Obesity" The New England Journal of Medicine, 387(3) https://doi.org/10.1056/NEJMoa2206038
* Terms and conditions apply.
This article was reviewed and approved by Qutayba Almerie MD, MSc, FRCS on 14 July 2025.
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