Tirzepatide name brands explained: Mounjaro, Zepbound and what's actually available in the UK

Step 1: understand why tirzepatide has more than one name

Pharmaceutical companies register brand names country by country. Eli Lilly chose Mounjaro as the name for tirzepatide in the UK (and across most markets where it holds a licence), while the US brand name is Zepbound. Same molecule, same Eli Lilly factory, two different regulatory jurisdictions, and therefore two different names. If you search for tirzepatide online and see Zepbound results, those pages are aimed at US readers. Zepbound is not a product that exists on a UK pharmacy shelf.

This distinction matters more than it might seem. Dosing presentations, approved strengths and the labelling on the pen can differ between markets. Someone importing or sourcing a US-labelled product would be receiving medicine that the MHRA has not assessed for the UK population in that form. The MHRA has warned publicly about the risks of sourcing weight-loss medicines outside the licensed supply chain, and large quantities of illegally traded pens have been seized across the UK. Worth checking: if you can look up a seller on the GPhC pharmacy register in under a minute, do it before you hand over any payment details.

Step 2: know which brand names are licensed for which use in the UK

Mounjaro holds two separate UK licences. The first covers weight management in adults with a BMI of 30 or above, or 27 and above where at least one weight-related condition is present. The second covers type 2 diabetes. The pen looks identical in both contexts, the clinical indication differs, not the device. This is why you will sometimes read about Mounjaro in diabetes coverage and sometimes in weight-loss coverage; it genuinely straddles both.

There is no other UK-licensed brand name for tirzepatide, and you can get a full picture of what is currently available by browsing the tirzepatide brands that hold a UK licence. If a seller offers you tirzepatide under any other name, or claims a new brand has been approved, that is a red flag. You can read the full clinical background on how Mounjaro got its brand name and what the approval process involved. The NHS tirzepatide medicine page confirms Mounjaro as the licensed product and is a useful reference point if you want an official cross-check.

Step 3: understand what Mounjaro actually is and how it differs from the other weight-loss injections

Mounjaro belongs to a class of medicines called dual GIP and GLP-1 receptor agonists. It activates two gut-hormone receptors involved in appetite regulation and blood-sugar control, slowing how quickly the stomach empties and increasing feelings of fullness after eating. The other main injectable weight-loss medicine in the UK, Wegovy, works on the GLP-1 receptor only. Mounjaro's dual action is what makes it structurally distinct, and the only medicine of its kind licensed for weight management in this country.

In the SURMOUNT-1 clinical trial, involving thousands of adults with obesity, participants taking the 15mg dose saw an average body-weight reduction of around 20 to 21 percent over 72 weeks. That figure comes from the trial published in the New England Journal of Medicine; the NICE technology appraisal (TA1026) drew on it when recommending tirzepatide for NHS use. A cost comparison of Mounjaro in the UK may also be useful if you are weighing up the private-treatment route. Different brands and price points reflect different service models, not different medicines, the molecule is the same wherever the pen is legitimately dispensed.

Step 4: check what any UK prescriber or pharmacy can and cannot supply

Because Mounjaro is a prescription-only medicine, no UK pharmacy can legally dispense it without a valid prescription from a registered prescriber. A prescriber who has reviewed your clinical history decides both whether tirzepatide is appropriate and which dose to begin with, the starting dose of 2.5mg is a tolerability step; the prescriber titrates upward from there based on how you respond. Questions about whether different brands of tirzepatide exist beyond Mounjaro in the UK are best answered with a clear no, at least for now.

At nume, every consultation is read by a GPhC-registered Independent Prescriber on the same day, a real clinician, not an automated decision system. If you are already on treatment elsewhere and considering a transfer, or simply want to understand your options, our clinical team is set up to talk you through the specifics. For a broader look at what weight-loss treatments are currently available, the weight-loss treatments overview sets out the landscape clearly. When you are ready to take the next step, check your eligibility with a free consultation.