The names of weight loss injections licensed in the UK — and what they actually do

Step 1, Start with the active ingredient, not just the brand

When people search for weight loss injection names, they usually find brand names first. That's a reasonable starting point, but the active ingredient sitting behind the brand is what determines how a medicine works, who it's licensed for, and what side effects to expect.

Mounjaro's active ingredient is tirzepatide. It works on two gut-hormone receptors simultaneously (GIP and GLP-1) slowing gastric emptying, reducing appetite signals, and improving blood-sugar regulation. It is the only dual-agonist weight-loss medicine licensed in the UK. Clinical trials in the SURMOUNT programme (SURMOUNT-1, published in the New England Journal of Medicine, involved 2,539 adults) recorded average body-weight reductions of around 20–21% at the 15 mg maintenance dose over 72 weeks.

Wegovy's active ingredient is semaglutide. It targets the GLP-1 receptor alone. The titration pathway runs from 0.25 mg through to a 2.4 mg maintenance dose; a higher 7.2 mg dose was approved by the MHRA in early 2026 for eligible adults. The STEP 1 trial (also in the New England Journal of Medicine) recorded around 15% average weight reduction over 68 weeks at 2.4 mg. Knowing the ingredient name helps you verify supply, cross-reference with your GP, and spot products that are not what they claim to be.

You can explore the drug names behind UK weight loss injections in more detail if you'd like the full pharmacological picture.

Step 2, Understand why some familiar names don't belong on the licensed weight loss list

Ozempic is probably the most widely mentioned name in media coverage of GLP-1 medicines. It contains semaglutide (the same active ingredient as Wegovy) but it is licensed in the UK for type 2 diabetes, not weight management. Prescribing it off-label for weight loss is not the same as using a medicine with a weight-management licence, and it is not something a regulated weight-loss service should be offering for that purpose.

Saxenda (liraglutide) is another name that circulates. It does hold a UK licence for weight management, but it is injected daily rather than weekly and has largely been superseded by the newer once-weekly options in clinical practice. Rybelsus is oral semaglutide but in the 3 mg, 7 mg and 14 mg tablet strengths licensed for diabetes, not the weight-loss tablet schedule.

The MHRA is clear that GLP-1 medicines are not assessed or licensed for quick or cosmetic weight loss, and that supply without a valid prescription is illegal. If you come across a seller offering injections under any of these names without a clinical assessment, that is a significant safety concern. The MHRA's Yellow Card scheme exists partly to receive reports of suspect sellers and counterfeit products.

A fuller run-down of how brand names and licensed indications map to each other is available on our weight loss injection brand names page.

Step 3, Know what a legitimate prescription actually involves

Both Mounjaro and Wegovy are Prescription-Only Medicines. That means a qualified prescriber must review your medical history, current medicines, BMI, and relevant conditions before deciding whether either is appropriate. The licence covers adults with a BMI of 30 or above, or 27 or above where at least one weight-related condition is present, but BMI alone is not a green light. Contraindications, existing health conditions and other medicines all factor in.

At nume, a GPhC-registered Independent Prescriber reviews every consultation personally, a real clinician, reading your answers the same day. Once approved, the pen is dispatched from our own GPhC-registered pharmacy and arrives via DPD the next working day, in plain, unbranded packaging with a tracking link on your phone. The pen itself is a pre-filled KwikPen (Mounjaro) or Wegovy pen; each contains four weekly doses.

If you're thinking about costs alongside clinical suitability, our weight loss injections prices page sets out what private treatment typically involves and what a transparent price should include. For a broader overview of how these medicines fit into a wider treatment plan, the weight loss treatment overview covers lifestyle, eligibility and the clinical pathway in one place.

Step 4, Match the name to the right starting point for you

Now that the names are clear, the practical question is which medicine a prescriber might consider for you, and through what route. Both Mounjaro and Wegovy are available on the NHS, but access is phased and the eligibility thresholds are strict. NICE recommends tirzepatide (TA1026, updated September 2025) for adults with a BMI of 35 or above plus at least one weight-related comorbidity through the NHS; lower thresholds apply for South Asian, Chinese, Middle Eastern, Black African or African-Caribbean backgrounds under that guidance. If you are based in the capital and considering private treatment, our weight loss injections London page explains what local access looks like and how the clinical pathway works through a regulated online pharmacy.

Our guide to weight loss injections covers eligibility in more depth, and our complete list of weight loss injection names covers every product name that surfaces in searches, with notes on each one's licensing status. If you'd like to talk through which option suits your situation, our clinical team profile at Mostafa Damghani explains who reviews your consultation and what their qualifications are.

These are serious prescription medicines. Getting the name right is only the first step; getting the clinical assessment right is what keeps the process safe. Speak to our prescribers to start that conversation.