How Many Weight Loss Injections Are There — and Which Are Licensed in the UK?

Which injections are actually licensed for weight loss in the UK?

The short answer: two. Mounjaro and Wegovy are the only injectable medicines the MHRA has authorised specifically for weight management in UK adults. You may have come across other names (Ozempic, Saxenda, Victoza) and it is worth being clear about each.

Ozempic is also semaglutide (the same active ingredient as Wegovy), but its UK licence covers type 2 diabetes, not weight management. Using it off-label for weight loss is a different matter legally and clinically, and our guide to what weight loss injections are available covers that distinction in detail. Saxenda (liraglutide) holds a UK weight-management licence but is a daily injection that predates both Mounjaro and Wegovy; it is not dispensed by nume. The NHS medicines page for tirzepatide is a good starting point if you want to read the official patient-level information on Mounjaro.

So when people ask whether there is an injection for weight loss that is genuinely available to them in the UK, the honest, practical answer for UK adults in 2025 and 2026 is two current options with full weight-management authorisation: Mounjaro and Wegovy. Everything else either has a different licensed purpose or is not available in the UK at all (Zepbound, for instance, is the US brand of tirzepatide and does not exist as a UK product).

How do Mounjaro and Wegovy actually differ from each other?

Both slow gastric emptying and reduce appetite (the shared mechanism of GLP-1 receptor agonism) but Mounjaro goes further by also activating GIP receptors, making it the only dual-agonist weight treatment licensed in the UK. In the SURMOUNT-5 trial, a 72-week head-to-head study published in the New England Journal of Medicine in 2025, tirzepatide produced greater average weight reduction than semaglutide 2.4mg. SURMOUNT-1 (also published in the NEJM) reported average body-weight reductions of around 20–21% at the highest tirzepatide dose over 72 weeks.

Wegovy's STEP 1 trial reported around 15% average weight reduction over 68 weeks at the 2.4mg weekly dose. A higher 7.2mg dose of Wegovy was approved by the MHRA in early 2026, with trial data suggesting average losses approaching those seen with tirzepatide 15mg. You can read more about how both injections work in detail on our treatments overview.

The injection formats are similar: both are once-weekly subcutaneous injections using pre-filled pens, given into the abdomen, thigh or upper arm. Neither requires refrigeration during active use, though both should be stored in the fridge between doses, with the specific room-temperature window detailed in the Patient Information Leaflet for each. A good habit many people settle into is keeping the pen in the fridge door and setting a weekly phone reminder for the same day. That consistency matters more than the exact time of day.

Which medicine is more suitable for a particular person depends on their medical history, any other conditions, and what their prescriber finds during assessment. It is not a decision made by comparing trial percentages alone.

What about the number of injections a course actually involves?

Both treatments are once-weekly injections with no defined end point built into the licence, they are intended to be used alongside a reduced-calorie diet and increased activity for as long as clinically appropriate. There is no "course" of ten injections and you are done. How many injections your treatment involves is therefore a question answered over time, in conversation with your prescriber, based on how your body responds and what your health goals are.

Mounjaro starts at 2.5mg (a dose designed to let your body adjust, not to produce immediate weight change) and is titrated upward roughly every four weeks by the prescriber. Wegovy follows a similar stepped approach from 0.25mg through to 2.4mg (or 7.2mg at the highest dose now available). The titration schedule affects how many pens you go through before reaching the maintenance dose, which is why the total number of shots per pen is a practical question worth understanding before you start.

People find their way to these treatments at different life stages, after years on NHS waiting lists, after a GP referral, or independently through a regulated private pharmacy. Some start in January, some after a summer where they felt their health was slipping. A few of the patients our prescribers see start just after payday, when the decision that has been sitting in the back of their mind finally feels manageable. Whenever the timing works for you, the clinical process stays the same.

How do I know which option (and which service) is safe to use?

Both Mounjaro and Wegovy are prescription-only medicines, which means the law requires a prescriber to assess you before any supply. That assessment protects you: it checks for contraindications, considers any other medicines you take (the interaction between tirzepatide and oral contraceptives is one example that needs addressing from day one), and reviews whether the dose is right for where you are in treatment.

The MHRA has issued public warnings about fake weight-loss pens sold online, with around 20 million doses of illegally traded weight-loss medicines worth roughly £45 million seized in 2025 alone, some counterfeits have contained insulin rather than the labelled medicine. The MHRA Yellow Card service lets you report suspected fakes. Any legitimate pharmacy supplying these medicines can be verified on the GPhC register; our pharmacy's registration number is 9012878, checkable at the GPhC website.

If you are considering treatment through a private route, understanding what legitimate supply looks like is a worthwhile first step. For a broader look at the treatment landscape, our weight loss overview sets out what is currently available and how the options compare. When you are ready to talk to a clinician about your own situation, our prescribers are there, start your free consultation and a GPhC-registered Independent Prescriber will review it the same day.