Guide · GLP-1 research
Retatrutide in Europe
Peptika Redaktion · Published
Short answer: retatrutide is not approved in the EU or anywhere else. Eli Lilly is testing it in the phase 3 programme TRIUMPH; the first phase 3 results were published in May 2026. Until a marketing authorisation is granted, retatrutide is available in Europe only in clinical trials and as reference material for laboratory research.
What retatrutide is
Retatrutide (development code LY3437943) is a triple agonist: one molecule that activates the receptors for GIP, GLP-1 and glucagon. Semaglutide acts on GLP-1 only and tirzepatide on GIP and GLP-1. The glucagon component is thought to raise energy expenditure and fat breakdown in the liver, which is why retatrutide is also studied in fatty liver disease.
| Semaglutide | Tirzepatide | Retatrutide | |
|---|---|---|---|
| Receptors | GLP-1 | GIP, GLP-1 | GIP, GLP-1, glucagon |
| Status in the EU | approved (Ozempic, Wegovy) | approved (Mounjaro) | not approved, phase 3 |
| Dosing in trials | once weekly | once weekly | once weekly |
The studies
- Phase 2 (Jastreboff et al., NEJM 2023): 338 adults with obesity. After 48 weeks, weight loss in the highest dose group averaged 24.2 %, against about 2 % with placebo.
- TRIUMPH-1 (phase 3, May 2026): topline results from Eli Lilly reported an average weight loss of 28.3 % after 80 weeks with the highest dose (12 mg), 25.9 % with 9 mg and 19.0 % with 4 mg, against 2.2 % with placebo. The full publication is still pending.
- Further TRIUMPH studies cover type 2 diabetes, knee osteoarthritis, sleep apnoea and cardiovascular outcomes.
The most common side effects in the trials were gastrointestinal: nausea, diarrhoea, vomiting and constipation, mainly during dose escalation. Heart rate rose in a dose-dependent way. Details (German): Retatrutide Nebenwirkungen.
When could retatrutide be approved in Europe?
A marketing authorisation in the EU is granted by the European Commission after an assessment by the European Medicines Agency (EMA). Lilly has to submit the application first, usually once several phase 3 studies are complete. The EMA's standard assessment takes about a year. Any date before then is speculation.
Retatrutide offered online
Because there is no approved product, anything sold as "retatrutide" outside a clinical trial is not a medicine. In the EU it may only be offered as reference material for laboratory research, without dosing instructions or health claims. Products sold as ready-to-use pens or for weight loss are unauthorised medicines. More on the legal framework: Are peptides legal in Europe?
Research material from the EU
Peptika ships retatrutide as lyophilised reference material from Germany, with HPLC and LC-MS reports for every batch. Inside the EU there is no customs clearance; see Peptides from the EU. How to check the lab report: How to read a peptide COA.
Frequently asked questions
Is retatrutide approved in Europe?
No. Retatrutide has no marketing authorisation in the EU, the UK or the US. It is being tested in the phase 3 programme TRIUMPH.
When will retatrutide be available in Europe?
Only after Eli Lilly applies to the EMA and the European Commission grants an authorisation. The standard EMA assessment takes about a year from submission; no date has been announced.
How much weight loss did retatrutide show?
In phase 2, up to 24.2 % after 48 weeks. In the phase 3 study TRIUMPH-1, Lilly reported 28.3 % after 80 weeks with the highest dose (topline results, May 2026).
What is the difference between retatrutide and tirzepatide?
Tirzepatide activates the GIP and GLP-1 receptors; retatrutide additionally activates the glucagon receptor. Tirzepatide is an approved medicine, retatrutide is not.
Can I buy retatrutide in the EU?
Not as a medicine. It is sold in the EU only as reference material for laboratory research.