Tirzepatide Drug Names: What the Medicine Is Called and Why It Matters

You've seen three names in three different places (here's what's actually going on

Picture this: you read about "tirzepatide" in a news article, see "Mounjaro" on the pharmacy website, then notice an American forum mentioning "Zepbound") and you're not sure whether these are the same drug or three competing ones. It's a genuinely confusing corner of medicines naming, and it trips up a lot of people.

The answer is straightforward. Tirzepatide is the international non-proprietary name (INN), the official scientific label given to the molecule by the World Health Organisation so that every country, every prescriber and every researcher uses a consistent term. You'll see it in clinical-trial papers, on NHS medicines pages, and in regulatory documents. More about tirzepatide as a drug is covered in our overview if you'd like the full clinical picture.

Mounjaro is what Eli Lilly chose to call their tirzepatide product for the UK and European markets. Brand names are chosen by manufacturers and approved by regulators; they don't change what's inside the pen. When your prescriber writes "Mounjaro" on a prescription, they are prescribing tirzepatide, and when a clinical study reports tirzepatide results, they apply directly to Mounjaro. The relationship between Mounjaro and its generic name is worth reading alongside this page.

One misconception worth clearing up gently: some people assume that a "brand name" medicine is somehow stronger or more refined than its generic counterpart. With tirzepatide, there is no generic alternative in the UK yet, Mounjaro is the only licensed tirzepatide product here, and our guide to tirzepatide brand names explains how those naming conventions work across different markets. The distinction is purely about naming convention, not formulation.

Zepbound, Ozempic and other names you may have encountered, a plain guide

Zepbound is the brand name Eli Lilly uses in the United States for tirzepatide. It does not hold a UK marketing authorisation, is not available from UK pharmacies, and cannot be legally imported for personal use. Any seller in the UK advertising Zepbound by that name is not operating within the licensed supply chain. If you're based in the UK, Mounjaro is the only legitimate route to tirzepatide.

Ozempic is a name that comes up frequently in weight-loss conversations, but it refers to a different molecule entirely: semaglutide, manufactured by Novo Nordisk and licensed in the UK for type 2 diabetes, not for weight management. Wegovy (also semaglutide, also Novo Nordisk) holds the UK licence for weight loss. These are distinct products from tirzepatide, with a different mechanism (GLP-1 receptor agonism only, rather than tirzepatide's dual GIP and GLP-1 pathway). Mixing up these names when searching online can lead you to products that are licensed for a completely different condition. If you want to understand exactly how all the different product names relate to one another, our guide to tirzepatide names sets this out clearly.

There are also names associated with compounded semaglutide or tirzepatide circulating on social media, products sold without a formal brand name and, critically, without a UK marketing authorisation. The MHRA has warned explicitly about counterfeit and unlicensed weight-loss injectables; reporting any suspect product through the Yellow Card scheme helps protect other patients. A name you don't recognise, combined with a price that seems implausible, is a reasonable reason to pause.

What the names mean in practice when you're looking for treatment

Understanding the naming structure has a practical payoff. When you search for information, using "tirzepatide" retrieves the clinical evidence (trial data, NICE guidance, NHS medicines pages) that applies directly to the medicine you'd be taking. The NHS tirzepatide medicine page uses the INN precisely so that information stays accurate regardless of which brand name a country happens to use.

NICE recommended tirzepatide for eligible adults in England in December 2024 (TA1026), and NHS rollout is happening in phases through 2026 and 2027. Private prescribing follows the licensed eligibility criteria in the medicine's SmPC: adults with a BMI of 30 or above, or 27 or above alongside a weight-related health condition. Lower BMI thresholds apply for certain ethnic backgrounds under UK clinical guidance. None of that changes with the name, whether a document says tirzepatide or Mounjaro, the same eligibility criteria and clinical standards apply.

For an honest look at what treatment involves financially, our Mounjaro cost page covers what a private prescription typically includes and where hidden fees sometimes appear. Separately, if you're early in your research, our weight-loss treatment overview explains how the different licensed medicines compare as starting points.

If you'd like to talk through whether tirzepatide is appropriate for your situation, a real prescriber on our team will review your consultation the same day. Speak to our prescribers through a free consultation, no waiting list, and everything is included in a single transparent price.