GLP1 Europe › Retatrutide
Is retatrutide approved in Europe?
Short answer
No. Retatrutide has no marketing authorisation in the European Union, in the United Kingdom, or in any other country in the world. It is an experimental drug made by Eli Lilly and is still going through clinical trials.
Its first large Phase 3 trial reported results in May 2026 and they were strong. Eli Lilly has since said it intends to file for approval in the United States in the first quarter of 2027. It has announced no filing date for Europe, and no regulator has begun a review.
| Developer | Eli Lilly and Company |
|---|---|
| Research code | LY3437943 |
| Brand name | None. It has never been marketed. |
| What it targets | Three receptors: GLP-1, GIP and glucagon |
| Furthest stage reached | Phase 3 |
| European Union | Not authorised |
| United Kingdom | Not authorised |
| United States | Not authorised |
| Application filed with EMA | Not announced |
| Application filed with FDA | Not yet filed. Eli Lilly signalled a first-quarter 2027 submission. |
What is retatrutide?
Retatrutide is an injectable drug being developed for obesity and type 2 diabetes. It belongs to the same broad family as semaglutide and tirzepatide, the molecules sold as Wegovy, Ozempic and Mounjaro, but it works on more targets than either of them.
Your gut naturally releases hormones after a meal that tell the body it has eaten. Two of them are GLP-1 and GIP. Semaglutide imitates GLP-1. Tirzepatide imitates both GLP-1 and GIP. Retatrutide imitates those two and adds a third, glucagon, which is involved in how the body releases stored energy. That is why it is often called a triple agonist. The word agonist simply means a substance that switches a receptor on.
Adding the glucagon target is the interesting part and also the uncertain part. In theory it raises energy expenditure rather than only reducing appetite. In practice, glucagon activity is harder to balance, which is one reason the drug has taken a long time to work through trials.
Is retatrutide approved anywhere?
No. As of 14 August 2026, no medicines regulator anywhere has approved retatrutide. That includes the European Medicines Agency, which handles most EU-wide approvals, the Medicines and Healthcare products Regulatory Agency in the United Kingdom, and the Food and Drug Administration in the United States.
This matters more than it might sound. An unapproved drug has no agreed product information, no approved dose, no official list of who should avoid it, and no formal system collecting reports when something goes wrong. Approval is not a rubber stamp at the end of the process. It is the point at which all of that documentation becomes official.
The only routine legal way to receive retatrutide in Europe today is to take part in one of Eli Lilly's clinical trials.
What did the Phase 3 trial show?
On 21 May 2026, Eli Lilly published results from TRIUMPH-1, the first large Phase 3 trial of retatrutide in obesity. It enrolled 2,339 adults with obesity, or with overweight plus at least one weight-related health condition. People with diabetes were excluded and studied separately.
The main phase ran for 80 weeks. A smaller group of 532 participants with a body mass index of 35 or above continued to 104 weeks.
| Dose | Weight lost | Average amount |
|---|---|---|
| Placebo | 2.2% | 2.5 kg |
| Retatrutide 4 mg | 19.0% | 21.4 kg |
| Retatrutide 9 mg | 25.9% | 29.2 kg |
| Retatrutide 12 mg | 28.3% | 31.9 kg |
In the 104 week extension, the 12 mg group averaged 30.3 percent of body weight lost, around 38.6 kg. Just under half of that group, 45.3 percent, lost 30 percent or more of their starting weight. For context, that overlaps with the range usually associated with bariatric surgery, which is why the result drew so much attention.
One technical note that is worth understanding, because it explains why you will see different numbers quoted for the same trial. Researchers report two figures. The efficacy estimand estimates what happens in people who actually stay on the drug as intended. The treatment-regimen estimand includes everyone who started, whether or not they stopped early, so it is always the more conservative number. On the treatment-regimen basis the 12 mg figure was 25.0 percent rather than 28.3 percent. Neither is wrong. They answer slightly different questions.
An earlier Phase 2 trial, published in the New England Journal of Medicine in 2023, had already shown up to 24.2 percent weight loss at 48 weeks. TRIUMPH-1 largely confirmed that at a bigger scale and over a longer period.
What side effects were reported?
Mostly digestive, and more common at higher doses. These are the rates reported for the 12 mg group compared with placebo.
| Effect | Retatrutide 12 mg | Placebo |
|---|---|---|
| Nausea | 42.4% | 14.8% |
| Diarrhoea | 32.0% | 13.5% |
| Constipation | 26.1% | 10.9% |
| Vomiting | 25.3% | 4.8% |
| Altered skin sensation | 12.5% | 0.9% |
The last one, altered skin sensation or dysesthesia, is less familiar and has been reported more with retatrutide than with the GLP-1 drugs already on the market. It describes tingling, prickling or other unusual sensations in the skin.
People also stopped the trial because of side effects at a rate that climbed with the dose: 4.1 percent at 4 mg, 6.9 percent at 9 mg and 11.3 percent at 12 mg. That gradient is part of what regulators will weigh up. A drug that produces the best results at a dose one in nine people cannot tolerate is a more complicated approval decision than the headline number suggests.
If it is not approved, why is it sold online?
Because it is not being sold as a medicine. It is sold as a laboratory chemical, usually labelled "for research use only" and "not for human consumption".
That label is a real regulatory category. Research institutions genuinely need to buy experimental compounds, and there is a legitimate supply chain that serves them. What the label does not do is create a legal route for a member of the public to take an unapproved drug. In the European Union, supplying an unauthorised medicinal product for human use is prohibited under Directive 2001/83/EC. The label describes what the seller is permitted to supply. It says nothing about what a buyer is permitted to do.
Worth knowing
A certificate of analysis tests a sample from a batch. It is not a test of the specific vial you receive, it does not verify sterility, and it can be fabricated. Independent testing of grey market peptides has repeatedly found products that differ from their label in identity, purity or quantity. If a product does turn out to be contaminated or wrongly dosed, there is no regulator collecting the reports and no manufacturer with a legal duty to act.
None of that is an argument about what anyone should do. It is a description of what the approval system provides and what buying outside it does not.
How is retatrutide different from tirzepatide?
The clearest difference is the number of receptors each one activates, and the practical difference is that one is a licensed medicine and the other is not.
| Tirzepatide | Retatrutide | |
|---|---|---|
| Receptors | GLP-1, GIP | GLP-1, GIP, glucagon |
| Sold as | Mounjaro | Not marketed |
| EU status | Authorised | Not authorised |
| Long-term safety data | Several years of post-approval monitoring | Trial data only |
Comparing weight loss percentages across separate trials is unreliable, because the participants, trial lengths and measurement rules differ. Retatrutide's numbers do look higher than tirzepatide's, but no head to head trial has been published, so the honest position is that the comparison remains an estimate.
The seven steps to a European pharmacy
Nothing reaches a European pharmacy without clearing all of these. Two are done, one is running.
-
Phase 2 trial published
June 2023, New England Journal of Medicine. Up to 24.2 percent average weight loss at 48 weeks.
Done
-
First Phase 3 results: TRIUMPH-1
21 May 2026. An average of 28.3 percent at 80 weeks on the highest dose, 2,339 participants. Full breakdown.
Done
-
Remaining Phase 3 readouts
TRIUMPH-2 in type 2 diabetes and TRIUMPH-3 in cardiovascular disease, expected through the rest of 2026. Regulators usually want the full programme.
In progress
-
Filing with the US FDA
Eli Lilly signalled a first-quarter 2027 submission in July 2026, pushed back from an earlier end-of-2026 target.
Signalled Q1 2027
-
Filing with the EMA
Not announced. Companies frequently file in Europe after the United States.
Not announced
-
EMA review
Normally around a year from filing to decision.
Pending
-
National pricing and reimbursement
Each country then decides separately whether its health system pays. How that works.
Pending
The honest read
A European approval before 2028 would be fast, and that assumes the filing happens, the review runs smoothly, and nothing in the remaining trial data changes the picture. Any site quoting you a specific launch date is guessing, and most of the ones doing so also sell peptides.
When could retatrutide be approved in Europe?
Eli Lilly has given a date for the United States and not for Europe. What is known:
- In July 2026 Eli Lilly said it intends to file retatrutide with the United States FDA in the first quarter of 2027. That is a delay: the company had previously pointed at the end of 2026, and cited manufacturing and quality documentation as the reason for moving it.
- No European filing date has been announced. Companies do not always submit to the EMA and the FDA at the same time, and Europe frequently comes second.
- TRIUMPH-1 reported in May 2026, and further Phase 3 readouts from the programme were expected through the rest of 2026. Regulators usually want the full programme, not a single trial.
- Once an application reaches the European Medicines Agency, the review itself normally takes around a year. Each country then makes its own pricing and reimbursement decision after that, which adds more time before anyone can actually get it.
Putting those together, a European approval before 2028 would be fast, and that assumes the filing happens, the review goes smoothly, and nothing in the remaining data changes the picture. This page will be updated when a filing is confirmed.
Approval is also not guaranteed. Drugs with good Phase 3 results have been turned down or delayed over safety questions, manufacturing issues or gaps in the data. Treat any specific launch date you see online as speculation, particularly on sites that also sell peptides.
Common questions
- Can a doctor in Europe prescribe retatrutide?
Not as an ordinary prescription. There is no approved product information to prescribe against. Clinical trial enrolment is the standard route.
- Is retatrutide legal to possess in the EU?
This differs by country and depends on how national law treats unauthorised medicinal products, personal importation and customs. Supply for human use is prohibited EU-wide. Possession rules are national, and this page is not legal advice.
- Is retatrutide the same as Mounjaro or Wegovy?
No. Mounjaro is tirzepatide and Wegovy is semaglutide. Both are approved medicines. Retatrutide is a separate, unapproved molecule that acts on one more receptor than tirzepatide.
- Why is it sometimes called GLP-3?
That is an informal nickname referring to the three receptors it targets, not a scientific classification. There is no hormone called GLP-3.
Sources
- Eli Lilly and Company. "Lilly's triple agonist, retatrutide, delivered powerful weight loss in pivotal Phase 3 obesity trial." Press release, 21 May 2026.
- TRIUMPH-1 trial record, ClinicalTrials.gov identifier NCT05929066.
- Jastreboff AM, Kaplan LM, Frías JP, et al. "Triple-Hormone-Receptor Agonist Retatrutide for Obesity: A Phase 2 Trial." New England Journal of Medicine, 2023. DOI 10.1056/NEJMoa2301972.
- European Medicines Agency, medicines database, checked 14 August 2026.
- Directive 2001/83/EC of the European Parliament and of the Council on the Community code relating to medicinal products for human use.
This page describes the regulatory and clinical status of an experimental drug. It is not medical advice and it is not a recommendation to use or obtain any medicine. If you are considering treatment for obesity or type 2 diabetes, speak to a doctor or a pharmacist.