Names of Weight Loss Injection Drugs Licensed in the UK

The drug names you'll encounter, and what they mean

Start with the basics. A drug has a generic name (the scientific name for the active compound) and usually a brand name chosen by the manufacturer. In the weight-loss injection space, this trips people up constantly.

Tirzepatide is the generic name. Its UK brand name is Mounjaro, made by Eli Lilly. It works on two gut-hormone receptors simultaneously (GIP and GLP-1) which is what makes it the only dual-agonist weight-loss injection available here. The pen delivers a once-weekly dose, starting low and increasing gradually under prescriber guidance. You'll find more detail on how all of this works on our weight-loss injections overview.

Semaglutide is the other generic name. Its weight-loss brand is Wegovy, made by Novo Nordisk. Semaglutide is a GLP-1 receptor agonist, it activates one of the two pathways that tirzepatide targets. You may also recognise the name Ozempic: same active ingredient, but Ozempic holds a UK licence for type 2 diabetes management, not weight loss. Using it for weight management is off-label and outside the scope of what a responsible prescriber would offer through a service like ours. The NHS medicines page on semaglutide explains the distinction between the two brands clearly.

Then there are names that simply don't apply in the UK. Zepbound is what tirzepatide is called in the United States; it has no UK licence and cannot be legally prescribed or dispensed here. If you see it offered on a UK website, that is a serious red flag. If you want a clear overview of every drug name you're likely to come across, our page covering what the weight loss injection drugs are actually called is a useful reference before reading further.

The names that cause the most confusion, Saxenda, Ozempic, Rybelsus

A few names come up in conversation all the time, often from people who've read about them online or heard a friend mention them.

Saxenda (liraglutide) is a GLP-1 injection licensed for weight management in the UK, made by Novo Nordisk. It requires a daily injection rather than once-weekly, and it is an older drug in this class. It is not dispensed by every provider, and its trial results show more modest weight reduction than Mounjaro or Wegovy. If a Saxenda keyword brought you here, our guide to weight-loss drug injections covers the fuller picture.

Ozempic is regularly described in the press as a weight-loss drug, which makes it one of the most misunderstood names in this space. It contains semaglutide and is effective for weight reduction, but its UK authorisation is specifically for type 2 diabetes. It is not prescribed for weight management through legitimate UK services. The MHRA is explicit on this point.

Rybelsus is oral semaglutide, but again in tablet strengths (3 mg, 7 mg, 14 mg) licensed for type 2 diabetes, entirely separate from the new Wegovy tablet (25 mg maintenance dose) licensed for weight loss. If you're curious about the oral option, our page on how the injection compares to other formats gives useful context.

Getting these names right matters practically, not just academically. Someone searching for Ozempic or Saxenda online is at higher risk of landing on an unverified seller. The MHRA Yellow Card scheme allows anyone to report a suspected counterfeit or unsafe seller, worth bookmarking.

What separates Mounjaro and Wegovy on the evidence

Once you've sorted the name confusion, the real question is usually: which of the two licensed injections might suit me?

In clinical trials, Mounjaro produced average weight reductions of around 20–21% over 72 weeks at the highest dose, in participants without diabetes. The SURMOUNT-5 trial, published in the New England Journal of Medicine in 2025, ran Mounjaro directly against Wegovy in a head-to-head comparison and found tirzepatide produced greater average weight reduction. That said, Wegovy's results in the STEP 1 trial (around 15% average weight loss at 2.4 mg) are substantial by any measure, and the newer 7.2 mg maintenance dose narrows the gap further.

Neither number tells you what will happen to you specifically. Starting dose, how your body responds, any other medicines you take, and your medical history all shape that picture. For some people semaglutide is the better-evidenced or better-tolerated choice; for others tirzepatide is more appropriate. That decision sits with a prescriber, not with a comparison table. It is also worth being aware that some people ask about side effects beyond the commonly discussed digestive ones, and our dedicated page on weight loss injections and vision issues addresses one area that comes up more than you might expect.

If you'd like to understand how private treatment is typically priced before speaking to anyone, our guide to what weight-loss injections cost in the UK walks through what the market looks like honestly. One thing worth knowing now: a legitimate price always includes a prescription and clinical assessment, not just the drug itself.

How prescribing actually works for these drugs

Both Mounjaro and Wegovy are prescription-only medicines in the UK. That legal category means no pharmacy, however convenient, can dispense them without a valid prescription from a qualified prescriber who has assessed your health.

The licensed eligibility criteria are broadly similar for both: adults with a BMI of 30 or above, or 27 or above alongside at least one weight-related condition such as high blood pressure, high cholesterol or obstructive sleep apnoea. Lower BMI thresholds apply for some ethnic backgrounds under UK guidance. BMI alone is not the whole picture, a prescriber looks at your full health history before confirming suitability.

On the NHS, access to these medicines is phased and tied to specific eligibility criteria; waiting lists for Wegovy through specialist services can be long, and the Mounjaro rollout through GP practices (from April 2026) is progressing gradually. Private routes through a regulated online pharmacy avoid those waits, subject to clinical suitability. You can verify any online pharmacy on the GPhC pharmacy register, it takes about thirty seconds and it's the most straightforward way to check you're dealing with a legitimate service.

At nume, your consultation is read and responded to by a GPhC-registered Independent Prescriber on the same day. Your pen would sit in the fridge door when it arrives, discreet, unbranded, tracked by DPD. If you'd like to understand what clinical assessment actually involves, our FAQs cover the most common questions. When you're ready, speaking to our prescribers is a straightforward starting point.