Other weight loss injections: which ones are licensed, which ones work, and how to choose

The decision starts with what's actually licensed for weight loss

A common source of confusion is that several injectable medicines contain the same active ingredient used in diabetes drugs, but carry different licences. Ozempic, for example, contains semaglutide, as does Wegovy, but Ozempic is licensed for type 2 diabetes, not weight management. Prescribing it for weight loss would be off-label, and the MHRA is clear that GLP-1 medicines are not assessed or authorised for cosmetic weight loss. What you want, if you're looking at weight loss injections as a treatment route, is a medicine licensed specifically for that purpose.

As of summer 2026, the injections licensed in the UK for weight management are tirzepatide (Mounjaro), semaglutide (Wegovy), and liraglutide (Saxenda), and you can read a thorough breakdown of what weight loss injections are there to choose from in the UK. Tirzepatide and semaglutide are both once-weekly; liraglutide requires a daily injection. Each acts on receptors involved in appetite regulation and slows how quickly the stomach empties, which is why nausea is a common early side effect across all three. The mechanism overlaps; the potency, dosing schedule and clinical results differ. The NHS medicines page for tirzepatide and the equivalent for semaglutide set out the expected side-effect profiles clearly, and both are worth reading before starting treatment.

Liraglutide has been available longest and the evidence base is established, but the average weight reduction in trials was more modest than the newer medicines. It's worth knowing about, especially if someone recommends it to you, but it sits behind tirzepatide and semaglutide in the results data.

What the evidence says about each option, and why the gap matters

The clinical trial results across these three medicines are not interchangeable, and the differences are clinically meaningful. In SURMOUNT-1, tirzepatide at its highest maintenance dose produced average body-weight reductions of around 20 to 21 percent over 72 weeks, in thousands of participants without diabetes. Semaglutide 2.4mg produced around 15 percent average reduction over 68 weeks in the STEP 1 trial, a result that was genuinely impressive when it arrived, and still is. The MHRA-approved 7.2mg semaglutide dose, available as a single-dose Wegovy pen since April 2026, narrows that gap further, with trials reporting around 20.7 percent average loss over 72 weeks.

Head-to-head, the SURMOUNT-5 trial published in the New England Journal of Medicine in 2025 compared tirzepatide directly against semaglutide 2.4mg in adults with obesity and no diabetes. Tirzepatide produced greater average weight reduction. That's the most direct comparison available from randomised trial data, and NICE's appraisal of tirzepatide (TA1026) references these findings as part of its recommendation. Which result is achievable for any individual still depends on biology, adherence, lifestyle support and how long treatment continues, trial averages describe populations, not predictions.

You can explore what other weight loss injections exist in the UK in more detail, including how Saxenda fits the picture for people who may not be suited to the newer medicines.

Practical differences that often get overlooked

Beyond the headline weight-loss figures, there are practical factors that matter a lot once you're actually on treatment. Dosing frequency is one: a daily injection requires more routine discipline than a weekly one. Many people find it easier to build a once-weekly injection into a fixed day (a Sunday morning, say, before the week begins) than to remember a daily one. Both weekly options use pre-filled pens, and both need to be stored in the fridge between 2 and 8°C; for the exact room-temperature window for travel or short-term storage, the Patient Information Leaflet for your specific medicine is the definitive source.

Side effects across all three are predominantly gastrointestinal (nausea, loose stools, constipation, indigestion) most noticeable when starting or increasing a dose, and generally easing within a week or two. That said, tirzepatide carries a specific interaction with oral contraceptives: women taking the pill should add a non-oral method of contraception for the first four weeks of treatment and for four weeks after each dose increase, because absorption of the pill can be reduced. There is no equivalent evidence of this effect with semaglutide. This is the kind of nuance that belongs in a clinical conversation, not just a comparison article. Our weight-loss treatment page explains how a consultation at nume works.

If you're older and wondering how these medicines behave in that context, safety considerations for seniors covers the available evidence specifically. The short version is that age alone is not a disqualifier, but a prescriber needs to weigh it alongside other health factors.

How to make sense of this if you're deciding what to ask about

Most people arrive at this question from one of two directions: they've heard about a specific injection and want to know how it compares to others, or they've been on one and are wondering whether switching would help. Both are reasonable starting points. What they share is that the answer belongs in a clinical assessment, not a product comparison table alone.

A prescriber looks at your BMI, any weight-related conditions, your medication history, your kidney and liver function if relevant, and whether you've tried a weight-loss medicine before. The weight-loss treatment overview outlines how eligibility is assessed. If you've already narrowed things down and want to understand how the top options stack up, our guide to the 3 weight loss injections licensed in the UK covers each one clearly. At our registered pharmacy, a GPhC-registered Independent Prescriber reads every consultation personally. Not software, a named clinician, the same day you submit. There's no waiting list and no referral needed, though you do need to meet the clinical criteria for whichever treatment is appropriate. If you have questions before you start, our FAQs cover the most common ones, and our team is available seven days a week.

Choosing to start with a weight loss injection is a decision that a clinician can help you feel confident about, particularly if you want to understand exactly what to expect before your first dose. One practical note: if you order by 12pm on a working day and your consultation is approved that day, your treatment is dispatched the same afternoon and delivered free by DPD the next working day in plain packaging. It's a small thing, but it matters when you've finally decided to start.