The drug names behind weight loss injections, explained clearly

Tirzepatide: why the drug name matters as much as the brand

When NICE published its appraisal of tirzepatide in December 2024 (Technology Appraisal TA1026), it confirmed this was the first dual GIP and GLP-1 receptor agonist to receive a UK weight-management recommendation. The drug name (tirzepatide) tells you something the brand name Mounjaro does not: that it targets two separate receptor pathways rather than one. GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 (glucagon-like peptide-1) are both gut hormones released after eating; tirzepatide mimics both, slowing gastric emptying and reducing appetite through a broader hormonal signal than single-agonist medicines.

In the SURMOUNT-1 trial, which randomised 2,539 adults with obesity and no diabetes, participants on 15 mg tirzepatide achieved an average body-weight reduction of around 20–21% over 72 weeks. The SURMOUNT-5 head-to-head trial, published in the New England Journal of Medicine in 2025, found tirzepatide produced greater average weight loss than semaglutide 2.4 mg over the same period. These figures come from tightly controlled trials and should not be read as personal predictions, a prescriber assesses whether the drug is appropriate for you before anything is dispensed.

Tirzepatide is supplied as a pre-filled KwikPen, each containing four weekly doses, in strengths from 2.5 mg up to 15 mg. Treatment begins at 2.5 mg (a dose chosen for tolerability rather than therapeutic effect) and titration decisions belong to the prescriber. If you want to understand how weight loss injections work in practice, that page covers the injection process in more detail.

Semaglutide: one molecule, several brand names, different licences

Semaglutide is probably the most widely discussed drug name in this category, partly because it appears under four brand names: Wegovy (weight management injection), Ozempic (type 2 diabetes injection), Rybelsus (type 2 diabetes tablet) and (as of June 2026) Wegovy tablets (the first oral GLP-1 medicine licensed in the UK for weight management). The distinction matters in practice. Understanding which semaglutide brand carries which licence helps you identify what a prescriber can legally issue for weight management, as opposed to diabetes.

Wegovy injection carries a UK weight-management licence for adults with a BMI of 30 or above, or 27 or above with at least one weight-related condition. The NHS describes the full prescribing picture on its semaglutide medicines page. The standard maintenance dose was 2.4 mg weekly; the MHRA approved a 7.2 mg dose in January 2026, with a dedicated single-dose pen confirmed in April 2026 for adults with a BMI of 30 or above. In the STEP 1 trial, 2.4 mg semaglutide produced an average weight reduction of around 15% over 68 weeks in adults with obesity.

Ozempic is not a weight-loss medicine in the UK. A prescriber cannot lawfully issue it for that purpose. This confusion surfaces regularly because Ozempic and Wegovy share the same active drug, but the licence, the dosing and the clinical indication are different. If someone is offering you Ozempic for weight loss, that is a red flag worth taking seriously.

Liraglutide (Saxenda) and why the weekly injectables now dominate

Liraglutide was the first GLP-1 agonist to receive a dedicated UK weight-management licence, under the Saxenda brand. It is administered daily rather than weekly, and average weight loss in clinical trials was lower than what subsequent agents have shown. If you want a broader picture of what the weight loss injection drugs are actually called, liraglutide remains on that list, but both NICE and most prescribers now weigh it against the stronger evidence base for tirzepatide and semaglutide. Some people do still use Saxenda, particularly where the newer agents are contraindicated or unavailable.

It is worth noting that liraglutide (Victoza) is also licensed for type 2 diabetes under a separate brand name, following the same pattern as semaglutide. The active drug is the same; the brand, strength and licence differ.

What these drug names mean for anyone researching private treatment

Knowing the drug name (not just the brand) is genuinely useful when you're comparing providers or checking what you're being prescribed. It lets you verify the product against the GPhC pharmacy register, cross-reference the SmPC, and ask informed questions of a prescriber.

At nume, every patient's consultation is reviewed the same day by a real GPhC-registered Independent Prescriber, not automated software. The treatment options page sets out which medicines are available and what the consultation covers. For anyone who wants to compare the weight loss injections by name before looking at costs, that page is a useful starting point before making a decision, and if you'd also like to browse the names of all weight loss injections available in the UK, that page brings them together in one place so you can see the full picture of what these weight loss injections are actually called before committing to a provider. The cheapest listing doesn't always reflect what's included or who's doing the clinical review.

One practical note: if you're planning to start treatment around a bank holiday or need delivery before a particular week, ordering by 12pm on a working day means same-day dispatch once clinically approved, with free next-working-day tracked delivery through DPD. Worth factoring in if payday or school holidays are your natural planning point.

These are all Prescription-Only Medicines. A prescriber decides whether any of them is appropriate for you, based on your health history and current circumstances, not on which drug name you came in asking for. Speak to our prescribers to start that conversation.