Semaglutide and GLP-1: are they the same thing?

You've searched this because someone called it a 'GLP-1' and you want to know what that actually means

It's a reasonable source of confusion. Clinicians, journalists and patients often use 'GLP-1' as shorthand for the whole family of weight-loss injections, when really it refers to a specific hormone your small intestine releases after a meal. That hormone (glucagon-like peptide-1) signals to your brain that you are full, slows the passage of food through your stomach, and nudges the pancreas to release insulin. The catch is that your own GLP-1 is broken down within minutes. It works, briefly, and then disappears.

Semaglutide was designed to solve exactly that problem. Scientists attached the semaglutide GLP-1 sequence to a fatty acid chain that binds to albumin in the blood, keeping the molecule circulating for around a week. The result is a drug that sits on the same GLP-1 receptors and produces the same appetite-suppressing, stomach-slowing effects, but does so continuously, which is why a single weekly injection can meaningfully change how hungry someone feels across seven days. The NHS semaglutide medicines page gives a clear overview of how it works and what to expect.

So when someone says 'I'm taking a GLP-1', they almost certainly mean they are taking a medicine from the GLP-1 receptor agonist class, and if you are wondering whether GLP-1 is the same as semaglutide, the short answer is that semaglutide is one of the most widely used members of that class.

The branded names make this murkier than it needs to be

Semaglutide reaches UK patients under two brand names. Wegovy is licensed for weight management in adults with a BMI of 30 or above, or 27 or above alongside a weight-related health condition. Ozempic carries the same molecule but is licensed specifically for type 2 diabetes. The MHRA is clear that Ozempic is not licensed for weight loss, and presenting it as such would be misleading, the distinction is about the licensed indication, not the chemistry.

There is a common misconception worth letting go of gently: some people assume that because Ozempic and Wegovy contain the same drug, they are interchangeable or that one can be obtained more easily than the other. In practice, both are prescription-only medicines requiring clinical assessment. A prescriber assesses which medicine, at which dose, suits the individual patient's circumstances. The brand name on the packaging does not change that requirement.

Oral semaglutide adds another layer. The Wegovy tablet (approved by the MHRA in June 2026 as the UK's first licensed oral GLP-1 medicine for weight management) contains the same semaglutide molecule taken once daily as a tablet, escalating from 1.5 mg up to a 25 mg maintenance dose. Rybelsus is also oral semaglutide, but it is licensed for type 2 diabetes, not weight loss, and its dose strengths are entirely different. If you are researching the relationship between Wegovy and semaglutide, that distinction between the two oral products is one of the most practically important things to understand.

Where tirzepatide sits in this picture

Mounjaro (tirzepatide) is frequently described alongside semaglutide as a GLP-1 medicine, and that is partly correct. Tirzepatide does activate GLP-1 receptors, and understanding how GLP-1 and semaglutide relate to each other helps clarify why tirzepatide is described as a dual agonist rather than a GLP-1 receptor agonist alone, since it also activates GIP receptors, a second gut-hormone pathway. This places it in the same broad family of incretin-based medicines but gives it a distinct pharmacological profile.

Clinical trials have compared the two directly. In the SURMOUNT-5 trial, published in the New England Journal of Medicine in 2025, tirzepatide produced greater average weight reduction over 72 weeks than semaglutide 2.4 mg. NICE's appraisal of tirzepatide, published as TA1026, references that indirect comparison in its committee discussion. Whether tirzepatide or semaglutide suits a given individual is a clinical question; the mechanism difference is one of the things a prescriber weighs up. For a broader look at how these medicines compare, our weight-loss treatments overview covers the licensed options side by side.

If you are trying to understand your own options, our prescribers are the right people to ask. You can read about our clinical team to get a sense of who reviews consultations, and the FAQs page covers a number of the practical questions that come up most often. For anything not covered there, the contact page is the quickest route to a direct answer.

One practical note on cost: if you are weighing up private treatment, the Wegovy pricing page sets out what affects the cost of semaglutide in the UK, including what a legitimate private prescription should include. When you are ready to explore whether treatment is suitable for you, check your eligibility with a free consultation, reviewed the same day by a GPhC-registered Independent Prescriber.