Retatrutide Brand Name: Why It Doesn't Have One Yet (UK)

Published on: April 24, 2026

Medically reviewed by

Ashis Tandukar

Superintendent Pharmacist · Reg: GPhC No. 2084170

If you've been researching new weight loss medications, you've probably noticed something strange about retatrutide. Search for "Mounjaro" and Eli Lilly's polished blue-and-white branding fills the screen. Search for "Wegovy" and you get Novo Nordisk's injector pen. Search for "retatrutide" and you get a chemical name, a development code, and a nickname borrowed from the people making TikToks about it.

There's a reason for that. Retatrutide doesn't have a brand name yet. Not in the UK, not in the US, not anywhere in the world.

What retatrutide is actually called

Retatrutide is the official generic name, assigned by the World Health Organisation through its International Nonproprietary Names (INN) programme. Every medicine that reaches the regulatory finish line gets one of these. Semaglutide is an INN. Tirzepatide is an INN. Paracetamol is an INN. They're the names used in scientific papers, regulatory documents and medical curricula, regardless of which company ends up selling the drug.

Alongside the INN, Eli Lilly — the company developing retatrutide — uses an internal development code: LY3437943. You'll see this code throughout ClinicalTrials.gov and the academic literature. If you're reading a paper about retatrutide and it suddenly switches to LY3437943, it's the same compound.

Then there's the nickname. Retatrutide is often called "triple G" (or sometimes "triagonist") because it activates three receptors at once — GLP-1, GIP and glucagon. The nickname stuck partly because it's memorable and partly because it captures what makes retatrutide interesting in the first place. Semaglutide (the drug in Ozempic and Wegovy) hits one receptor. Tirzepatide (the drug in Mounjaro) hits two. Retatrutide hits three.

So when someone asks what is the brand name of retatrutide?, the honest answer is: it doesn't have one. It has a generic name, a development code and a shorthand the internet invented.

Why there's no retatrutide brand name yet

A pharmaceutical brand name doesn't exist until a regulator approves the drug for sale. Brand names are proprietary trade marks — they're proposed by the manufacturer, trademarked, and submitted for approval alongside the product itself. Regulators then check that the proposed name isn't confusingly similar to existing medicines and won't mislead prescribers or patients. Only once all of that is signed off can the drug be sold under that name.

Retatrutide is still in Phase 3 clinical trials. It has not received a Marketing Authorisation from the Medicines and Healthcare products Regulatory Agency (MHRA) in the UK, the European Medicines Agency (EMA) in Europe, or the Food and Drug Administration (FDA) in the United States. Until one of these regulators approves it, retatrutide remains what the rules call an investigational medicinal product — and investigational products don't get commercial brand names.

Eli Lilly hasn't publicly announced a working brand name. Industry watchers speculate it will probably start with the prefix "reta-" (much like tirzepatide became Mounjaro for diabetes and Zepbound for weight loss in the US, and semaglutide became Ozempic for diabetes and Wegovy for weight loss). But speculation is just speculation. The actual name will appear when the approval application is made public.

When could a retatrutide brand name arrive in the UK?

Once Phase 3 data is complete, the path to a UK brand name looks roughly like this:

1. Eli Lilly submits a Marketing Authorisation Application to the MHRA.
2. The MHRA reviews the full safety, efficacy and quality dossier.
3. If approved, the drug launches in the UK under its registered brand name.
4. NICE separately assesses it for NHS availability and value for money.

The timing isn't guaranteed. Lilly has said publicly that availability "around 2026" is plausible, but regulatory review can stretch that. NICE technology appraisals for NHS use typically take another 6–12 months on top. A realistic picture is: a retatrutide brand name could appear on the UK private market at some point in 2026 or 2027, with NHS access following later. Anyone telling you a specific launch date right now is guessing.

For context on how long this process can take, our guide on how to get retatrutide in the UK walks through the actual access routes currently available (which, in April 2026, still amounts to clinical trials only).

Why the brand name question matters: the counterfeit problem

Here's where the lack of a brand name becomes a safety issue rather than a marketing curiosity.

Retatrutide is widely discussed online but isn't available through any regulated channel in the UK. That gap has created a market for unlicensed versions. In December 2025, the MHRA raided a UK facility producing counterfeit retatrutide and tirzepatide for sale online. Products labelled as "retatrutide peptide," "retatrutide 10mg pen" or "retatrutide 40mg" are not the real thing. They're unlicensed compounds, often manufactured without pharmaceutical-grade controls, and with no guarantee of what's actually in the vial.

If you see retatrutide being sold on a website, through Instagram, via a "peptide" supplier or at an aesthetics clinic, that product is not legally available for weight loss in the UK. There is currently no regulated route to obtain retatrutide outside an authorised clinical trial.

This is the practical reason the brand name question matters. A real, approved brand name is your signal that a medicine has cleared regulatory review. Its absence means anything claiming to be retatrutide right now has not.

For more on the safety picture around this class of drugs, see our write-up on retatrutide side effects from the trial data and the broader guide on retatrutide availability, safety and alternatives in the UK.

How retatrutide compares to medicines that already have brand names

To anchor all this, here's how the three main GLP-1-based weight loss drugs currently line up:

Early Phase 2 data (published in the New England Journal of Medicine in 2023) showed some trial participants lost more than 20% of their body weight across 48 weeks on retatrutide. That's why it's generating so much interest. But those findings come from trials of a few hundred people — the Phase 3 programme, which enrols tens of thousands of participants, is what will determine whether retatrutide actually delivers on that promise when used more broadly.

It's also worth saying: retatrutide has not been compared head-to-head with tirzepatide or semaglutide in any published trial. Cross-trial comparisons are unreliable. Anyone presenting retatrutide as definitively "more effective" than Mounjaro is running ahead of the evidence.

If you're wondering about the dosing being studied, we've summarised the numbers in our guide to retatrutide dosage for weight loss.

If you're looking at retatrutide because your current treatment isn't working

If you've tried Wegovy or Mounjaro and not had the response you hoped for, the answer is rarely to wait 12–24 months for an unapproved medication. Much more often, it's one of these things:

• Your dose hasn't been optimised. Titration can take 6 months or more to reach a maintenance level that actually works for you.
• Side effects have limited your ability to stay on treatment, and a different approach (slower titration, a different injection day, anti-nausea support) might fix that.
• Lifestyle factors — sleep, protein intake, resistance training — haven't been addressed alongside the medication.
• You're in a plateau that will resolve with patience and small adjustments rather than a brand-new drug.

A clinician who takes the time to review your treatment properly will usually find something worth changing before recommending you hold out for a medication that may not reach the UK market until 2027. Our breakdowns of Wegovy cost in the UK and how to choose a Mounjaro provider are a good place to start if affordability or service quality is part of what's made things difficult.

The other names you'll see for retatrutide

Pulling everything together, here are the names and phrases you're likely to come across in the wild, and what each actually refers to:

• Retatrutide — the generic name (INN), assigned by the WHO. This is what regulators, scientists and prescribers use.
• LY3437943 — Eli Lilly's internal development code. Appears in clinical trial records and research papers.
• Triple G / triple agonist / triagonist — descriptive nicknames that refer to its mechanism of action (GLP-1, GIP and glucagon). Not official names.
• GLP-3 — occasionally used informally in the press to imply a next-generation GLP-1. Not a formal classification.
• Any brand name you see online right now — unofficial at best, counterfeit at worst.

If you're searching clinical trial databases or scientific publications, use retatrutide or LY3437943. These will give you the most accurate results. If you're on social media and see a specific brand name being sold, treat it with the same scepticism you'd apply to any other unlicensed medicine.

Medical disclaimer

This article is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional before starting any treatment.