The top 5 weight loss injections available in the UK right now

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

The five worth knowing about, in rough order of how commonly they appear in current clinical practice, are: tirzepatide (Mounjaro), semaglutide (Wegovy), liraglutide (Saxenda), naltrexone-bupropion (Mysimba, though this is a tablet rather than an injection), and older agents such as orlistat. For injectable options specifically, the list narrows to three.

Tirzepatide is the newest and, on current trial evidence, the most effective. It activates two gut-hormone receptors (GIP and GLP-1) slowing gastric emptying and reducing appetite through a dual mechanism no other licensed weight loss injection shares. In the SURMOUNT-1 trial, published in the New England Journal of Medicine, participants on the 15mg dose lost an average of around 20–21% of their body weight over 72 weeks. NICE recommended it for NHS use in England in December 2024 (TA1026).

Semaglutide (Wegovy) is a GLP-1 receptor agonist and has been available in the UK longer. The STEP 1 trial reported an average of roughly 15% weight loss at the 2.4mg weekly maintenance dose over 68 weeks. A higher 7.2mg dose was approved by the MHRA in early 2026, with trial data suggesting around 20.7% average loss, closing the gap with tirzepatide. NICE recommended it earlier, under TA875.

Liraglutide (Saxenda) is a once-daily GLP-1 injection, older and generally showing more modest results than either of the above. It remains licensed for weight management in the UK, though it is less commonly prescribed now that the weekly options are established. Beyond these three, the broader weight loss injections landscape includes medicines not licensed for weight loss at all in the UK, which is worth understanding before you decide anything.

How do these five injections actually compare on results and side effects?

Comparing them honestly means sitting with some uncertainty. Head-to-head data between all five does not exist in the way a single tidy table would suggest. What we do have is solid.

The SURMOUNT-5 trial (a direct head-to-head over 72 weeks in adults with obesity) found tirzepatide produced greater average weight reduction than semaglutide 2.4mg. That is the most rigorous comparison available for the top two. For liraglutide versus semaglutide, older indirect comparisons consistently favour semaglutide, and clinical practice has largely followed that direction.

Side effects across the class share a common profile: nausea, vomiting, diarrhoea, constipation, and fatigue. They are most noticeable when starting or moving up a dose, and for most people they settle within a few weeks. Pancreatitis is a rarer but serious risk the MHRA specifically flagged in a Drug Safety Update in January 2026, severe stomach pain that spreads to the back warrants urgent medical attention. The NHS medicines page for tirzepatide and its equivalent for semaglutide both carry the full side-effect profiles and are worth reading before you start either treatment.

One thing many people find reassuring: the side-effect profile does not automatically get worse with a more effective medicine. Tirzepatide's GI effects are broadly similar in frequency to semaglutide's in trial data, though individual experience varies. A clinical review before and during treatment exists precisely to manage this, adjusting timing, dose, and any other medicines you take.

If you want a fuller side-by-side breakdown, our guide to the top 3 weight loss injections currently used in UK clinical practice covers the evidence in more depth.

What about injections people mention online that aren't on this list?

This is a question our prescribers hear regularly, and it matters. Several medicines circulate online under the weight-loss label that are not licensed for that purpose in the UK. Ozempic is the most common: it contains semaglutide, but its UK licence is for type 2 diabetes, not weight management. Using it off-label for weight loss, obtained through channels that bypass a proper prescription, is a significant safety risk, and a legal one for whoever supplies it.

Then there are injections sold through social media or unofficial websites with no licensed status at all. The MHRA has warned publicly about counterfeit pens seized in the UK, including fake tirzepatide pens produced at an unlicensed site. If a seller is offering these medicines without a valid prescription from a registered prescriber, that is a red flag, not a shortcut.

The safe route is straightforward: a UK-registered prescriber, a GPhC-registered pharmacy you can verify on the GPhC register, and a genuine supply chain. You can check any online pharmacy's registration in seconds. It is worth doing before you hand over personal health information, let alone payment.

For people exploring how the private route actually works in practice, the guide to getting weight loss injections covers the process step by step.

Who is actually eligible, and what happens at a consultation?

Eligibility for weight loss injections in the UK follows the licensed criteria set out in each medicine's approval. The private route broadly mirrors this: Mounjaro and Wegovy are licensed for adults with a BMI of 30 or above, or 27 and above where at least one weight-related condition is present, things like high blood pressure, high cholesterol, obstructive sleep apnoea, or type 2 diabetes. Lower thresholds apply for some ethnic backgrounds under UK guidance. BMI alone does not decide it; a prescriber looks at your full health picture.

If you are wondering whether you might qualify, you are not alone, a lot of people sit in that uncertain middle ground, unsure whether their BMI or health history makes them a candidate. That is exactly what a consultation is for, and our guide to the top weight loss injections available in the UK can help you go in with a clearer sense of the options available.

At nume, a GPhC-registered Independent Prescriber reads every consultation personally on the day it comes in, your answers are not processed by software. There is photo-ID verification and live weight confirmation, and your GP is notified in line with GPhC guidance. If treatment is clinically suitable and you order before midday, it is dispatched the same day and arrives the next working day by tracked DPD. One price covers everything: consultation, prescription, medicine, and delivery. There are no subscriptions and no hidden charges. Current pricing is on the treatment page, and a full overview of the options we provide is on the weight loss treatment overview.

If you are ready to find out whether treatment is right for you, start your free consultation and a prescriber will review it the same day.