Semaglutide: the peptide name behind Wegovy and what it actually means

What exactly is a peptide, and why is semaglutide described as one?

A peptide is a short chain of amino acids, the same building blocks that make up proteins, just fewer of them linked together. Natural GLP-1 is itself a 30-amino-acid peptide released from cells in the gut wall within minutes of eating. Its job is to signal fullness to the brain, slow the rate at which the stomach empties, and prompt the pancreas to release insulin in a glucose-dependent way.

Semaglutide is a modified version of that peptide. Researchers at Novo Nordisk altered the amino acid sequence slightly and attached a fatty-acid side chain. That attachment lets semaglutide bind to albumin (a protein that circulates in the blood) which protects it from the enzyme dipeptidyl peptidase-4 (DPP-4) that would otherwise degrade it within two minutes, as it does natural GLP-1. The result is a peptide with a half-life of roughly one week, which is why a single weekly injection or daily tablet maintains steady levels throughout the treatment period.

The NHS patient information on semaglutide explains the molecule's action in plain language if you want a readable starting point alongside this page. For deeper pharmacological detail, the British National Formulary's semaglutide drug monograph is the professional reference UK prescribers consult. Understanding this background is also helpful when reading about semaglutide as a peptide in broader clinical contexts.

Does the peptide name change between Wegovy, Ozempic and the Wegovy tablet?

No. The active molecule (semaglutide) is the same peptide in each product. What differs is the formulation, dose, delivery route and, critically, the licensed indication.

Ozempic is a weekly subcutaneous injection licensed for type 2 diabetes in the UK. Its doses (0.5mg, 1mg, 2mg) are lower than the weight-management schedule and it holds no licence for weight loss from the MHRA. Wegovy uses the same peptide but at doses titrated up to 2.4mg (and now up to 7.2mg following the MHRA's April 2026 approval of a dedicated single-dose pen) specifically licensed for weight management in adults with obesity or overweight with a weight-related condition. The Wegovy tablet, approved by the MHRA on 11 June 2026 as the first oral GLP-1 weight-loss medicine licensed in the UK, uses semaglutide co-formulated with an absorption enhancer called SNAC; its maintenance dose is 25mg daily, a figure that looks very different from the injection schedule but reflects the oral bioavailability challenge rather than a greater amount of peptide reaching the bloodstream.

If you are trying to make sense of the differences in practice, our guide to Wegovy versus Ozempic covers the licensing distinction in more detail, and the Wegovy overview page sets out the full injection schedule. You can also explore whether the tablet or the injection might suit your routine on the weight-loss treatments overview.

Is semaglutide the same as other GLP-1 peptides used for weight loss?

GLP-1 receptor agonists share the same general mechanism (activating the GLP-1 receptor) but they are different peptides with different molecular structures, half-lives and clinical profiles. Liraglutide (Saxenda) is also a GLP-1 peptide licensed for weight management but requires daily injection and produces more modest average weight loss in trials. Tirzepatide, the peptide inside Mounjaro, activates both the GLP-1 and GIP receptors, a dual-agonist structure that makes it chemically distinct from semaglutide even though both are sometimes called GLP-1 medicines colloquially.

In clinical trials, semaglutide 2.4mg produced an average body-weight reduction of around 15% over 68 weeks in the STEP 1 study, published in the New England Journal of Medicine. The question of how different GLP-1 peptides compare is one our prescribers field regularly, the answer depends on the whole clinical picture, not just the molecule name. The page on GLP-1 peptides for weight loss explores the broader family if you want to read further, and our discussion of semaglutide's role in weight management covers the evidence in more depth.

Does knowing the peptide name help when considering treatment?

Practically, yes, in a few ways. First, it helps you read product information and clinical trial results accurately. STEP 1 and other SURMOUNT-programme papers refer to semaglutide and tirzepatide by their nonproprietary names; knowing which brand maps to which peptide stops confusion. Second, it matters for conversations about switching formulations: if you move from the Wegovy injection to the Wegovy tablet, the peptide is the same but the titration schedule restarts. A prescriber will guide that transition, but understanding the molecule helps you ask better questions.

Third, the peptide name is how the MHRA licenses and regulates these medicines. When the regulator approves a new indication (as it did for the MASH (fatty liver disease) indication for semaglutide in July 2026) the approval attaches to the molecule and product together, not interchangeably across brands. Storage routine is one small practical area where this knowledge helps too: the Wegovy injection pen lives in the fridge (2–8°C), while the Wegovy tablet needs no refrigeration and can travel in a handbag without a cold pack.

If you are weighing up whether semaglutide-based treatment is appropriate for your situation, the cost and treatment information page is a useful next step for context, and the semaglutide peptide dosing overview explains how the schedule works. At nume, every consultation is reviewed by a GPhC-registered Independent Prescriber, a real clinician reads your answers, not an algorithm. Speak to our prescribers to find out whether Wegovy is clinically suitable for you.