How much weight loss did retatrutide achieve in clinical trials?

In the Phase 3 TRIUMPH-1 trial of 2,339 adults with obesity, retatrutide produced up to about 25% average body weight loss at 80 weeks on the 12mg dose, rising to around 30.3% in higher-BMI patients. Around 45% of top-dose patients lost at least 30% of their body weight.

Retatrutide: The ‘Triple G’ Weight-Loss Injection Explained — and When Ireland Might See It

If you follow weight-loss news, you’ve probably heard the name retatrutide — often called the “triple G” or the next generation beyond Ozempic and Mounjaro. The trial results are genuinely striking. Here’s what the science actually shows, and the honest answer to the question everyone asks us at the counter: when can I get it in Ireland?

The short version: retatrutide has produced the largest weight loss ever seen from a weight-loss injection in late-stage trials — up to around 25% of body weight, and close to 30% in some patients. But it is not yet approved anywhere in the world. Realistically, Ireland is unlikely to see it before 2028.

What makes retatrutide different?

Ozempic and Wegovy work on one hormone pathway (GLP-1). Mounjaro works on two (GLP-1 and GIP). Retatrutide works on three — it adds a hormone called glucagon, which helps the body burn energy and use fat. That’s why it’s nicknamed the “triple agonist,” and it appears to be why the weight-loss numbers are higher than anything before it.

The clinical trial results, in plain figures

Retatrutide is being tested in a large programme of studies called TRIUMPH. The headline study, TRIUMPH-1, followed 2,339 adults with obesity for 80 weeks.

25%average body weight lost on the 12mg dose at 80 weeks (TRIUMPH-1)

30.3%average loss in higher-BMI patients in the extension — and still falling

45%of top-dose patients lost at least 30% of their body weight

To put that in context, that upper range approaches the kind of weight loss usually associated with bariatric (weight-loss) surgery — from an injection. Importantly, the weight loss had not plateaued when the main study ended, which is unusual.

Trial	Who	Result
TRIUMPH-1 (2026)	2,339 adults with obesity	Up to 25% weight loss at 80 weeks; ~30.3% in higher-BMI extension
TRIUMPH-4 (Dec 2025)	Obesity + knee osteoarthritis	28.7% weight loss at 68 weeks, plus real joint-pain relief
TRANSCEND-T2D-1 (Mar 2026)	Adults with type 2 diabetes	16.8% weight loss at 40 weeks

Sources: Eli Lilly Phase 3 announcement and the reporting summarised by the Pharmaceutical Journal, AJMC and Eli Lilly.

When will retatrutide be available in Ireland?

This is the honest part, and it matters. Retatrutide is not approved or for sale anywhere yet — not in the US, not in Europe, not in Ireland. The manufacturer, Eli Lilly, hasn’t even submitted it to regulators. Here’s the realistic road ahead:

Late 2026

Eli Lilly expected to submit retatrutide to the US regulator (FDA) for approval.

Late 2027 – early 2028

Possible US approval, after the standard review period.

2028 and beyond

European approval (via the EMA) typically follows the US, so Ireland would realistically be 2028 at the earliest — quite possibly later.

A serious safety word. Because retatrutide is generating so much hype, unlicensed “retatrutide” is already being sold online and through social media. Please do not buy it. It is not an approved medicine, nobody is checking what’s in the vial, and there is no pharmacist or doctor overseeing your safety. Counterfeit weight-loss injections have already put people in hospital in Ireland. If a route to any weight-loss medicine doesn’t involve a prescription and a pharmacy, it isn’t safe.

What can you actually do now?

The good news: highly effective, fully approved weight-loss medicines are available in Ireland today — and we dispense them from stock at Laois Pharmacy. Ozempic, Wegovy and Mounjaro each produce substantial, well-evidenced weight loss, and Mounjaro in particular has shown the strongest results of any medicine available right now.

Our approach is always GP-first: your own doctor decides whether treatment is right for you, we dispense it (usually same day), and we support you month to month. Not sure if you’d qualify? Our free BMI eligibility calculator takes two minutes.

Want to talk about the options available today?

Retatrutide is still years away — but you don’t have to wait to get started safely. Talk to our pharmacists about the licensed treatments in stock now.

Our Weight Management Service WhatsApp us — 085 840 7548

Retatrutide FAQs

Is retatrutide better than Mounjaro or Ozempic?

In trials, retatrutide produced greater average weight loss than any currently available medicine — up to around 25%, and close to 30% in some patients. But it is still experimental and unlicensed, whereas Mounjaro, Wegovy and Ozempic are approved and available now.

When will retatrutide be available in Ireland?

Realistically not before 2028, and possibly later. It has not yet been submitted to any regulator. US approval is expected around late 2027 to early 2028, with European and Irish availability following after that.

Can I buy retatrutide now?

No — not legally or safely. It is not an approved medicine anywhere. Anything sold online as “retatrutide” is unlicensed and unregulated, with real risk to your health.

How does retatrutide work?

It acts on three hormone pathways — GLP-1, GIP and glucagon — reducing appetite while also helping the body use energy and fat.

What weight-loss medicines can I get in Ireland right now?

Ozempic, Wegovy and Mounjaro are all available with a prescription. Laois Pharmacy dispenses them from stock, usually the same day, with GP-first support. See our weight management service.

Reviewed by Deirdre O’Donovan MPSI, pharmacist (registered since 1981), Laois Pharmacy, Portlaoise. Correct as of July 2026 — approval timelines are estimates and can change. This article is general information, not medical advice; always talk to your GP or pharmacist about your own situation.