What is the other name for tirzepatide — and does it matter which you use?

How regulators and manufacturers use names differently

Every licensed medicine has at least two names. The international non-proprietary name, or INN, is the scientific identifier agreed by the World Health Organisation so that clinicians, pharmacists and researchers across every country can refer to the same compound without confusion. Tirzepatide is that INN. Eli Lilly then chose Mounjaro as the brand name when it sought regulatory approval, first from the US FDA and later from the MHRA and the European Medicines Agency.

In the UK, the MHRA granted Mounjaro its licence for weight management and type 2 diabetes. That licence covers adults with a BMI of 30 or above, or 27 or above where at least one weight-related condition is present. Your prescriber uses the clinical name tirzepatide when writing to your GP or reviewing your notes; your pharmacy label will say Mounjaro; your pen itself is called a KwikPen. All three point to the same thing. You can read a plain-language summary of tirzepatide on the NHS medicines page for tirzepatide, which uses both names throughout.

Knowing this matters if you are searching online or comparing prices. If you are curious about what tirzepatide's brand name is and how it came to be chosen, that background can help you make sense of listings that use one term or the other, though only a GPhC-registered pharmacy dispensing from the licensed UK supply chain guarantees that the pen in your fridge is what it claims to be.

Why there is no other UK brand name, and what about Zepbound?

A common question our prescribers hear most weeks is whether Zepbound (which appears frequently in search results) is available in the UK. It is not. Zepbound is the brand name Eli Lilly uses in the United States; it refers to the same tirzepatide molecule but has never been submitted for MHRA approval as a separate UK product. Any seller offering 'Zepbound' in Britain is not selling a UK-licensed medicine.

Similarly, tirzepatide has no other licensed brand in the UK at the time of writing. The NICE technology appraisal TA1026, published in December 2024 and updated in September 2025, refers to the medicine throughout as 'tirzepatide (Mounjaro)', the standard convention for a single-brand medicine where the brand and the INN are effectively interchangeable in clinical use. If you see a different brand name attached to tirzepatide, treat it as a red flag.

For a deeper look at what the medicine itself involves, our page on what tirzepatide is covers the mechanism, the dual-agonist action on GIP and GLP-1 receptors, and how that differs from older weight-loss injections.

How the naming question connects to safe buying

Understanding that Mounjaro and tirzepatide are one and the same has a practical consequence: it makes it easier to spot products that are neither. The MHRA has warned repeatedly about counterfeit weight-loss pens sold through social media and unverified websites, including fake pens that contained substances other than what was claimed. Those sellers often use generic or unfamiliar names, vague labelling, or prices well below what a legitimately dispensed pen costs through a regulated UK pharmacy.

If you want to understand the range of names and terms associated with Mounjaro that appear in conversation and online (including colloquialisms you might encounter) that page unpacks them without adding to the confusion. It is also worth knowing that there is another name for tirzepatide that you may come across depending on which country's sources you are reading, and understanding why that name exists helps explain some of the variation you will see online. The short version: the only name that matters for safe access in the UK is the one on a prescription written by a registered prescriber, dispensed by a pharmacy you can verify on the GPhC register.

If you are thinking about treatment and want to understand what the process looks like from a cost perspective, the weight-loss treatments overview sets out what private treatment typically involves in plain terms.

What this means when you talk to a prescriber

Whether you call it tirzepatide or Mounjaro in your consultation makes no difference clinically. Prescribers use both terms freely. What does matter is that any assessment goes beyond the name: a prescriber should be looking at your BMI, your weight-related health conditions, your current medicines, and any contraindications before deciding whether this treatment is right for you. The tirzepatide starting dose of 2.5mg exists specifically to let your body adjust before any therapeutic increase, that is a clinical decision, not something to skip.

At nume, a GPhC-registered Independent Prescriber reads every consultation personally. If you order before noon on a working day and are found clinically suitable, your prescription is dispatched the same day and arrives with DPD the next working day in plain, unbranded packaging, about as low-key as the morning post. For a fuller picture of what Mounjaro involves before you decide, the Mounjaro information page is the place to start. When you are ready, check your eligibility with a free consultation.