GLP1 Europe › Molecules
The GLP-1 family: which molecule targets what
Short answer
These drugs differ mainly in how many hormone receptors they switch on. Liraglutide, semaglutide and orforglipron activate one. Tirzepatide activates two. Retatrutide activates three.
So far, more targets has meant more weight loss and more side effects. It has also meant a longer road to approval, which is why the most effective molecules are the ones you cannot get.
What is actually approved in Europe
Start with the drugs a European doctor can legally prescribe. Everything else in this article is either not approved here or not approved anywhere.
| Molecule | Receptors | How it is taken | Pivotal trialaverage weight loss |
|---|---|---|---|
| LiraglutideSaxenda, Victoza | GLP-1 | Injection, daily | SCALE, 56 weeks7.4% vs 3.0% placebo |
| SemaglutideWegovy, Ozempic | GLP-1 | Injection, weekly | STEP 1, 68 weeks14.9% vs 2.4% placebo |
| Semaglutide, oralWegovy tablets, Rybelsus | GLP-1 | Tablet, daily, on an empty stomach | OASIS 4, 64 weeks16.6% vs about 3% placebo |
| TirzepatideMounjaro | GLP-1 and GIP | Injection, weekly | SURMOUNT-1, 72 weeks22.5% vs 2.4% placebo |
| OrforglipronFoundayo. UK only, not EU | GLP-1 | Tablet, daily, any time, with or without food | ATTAIN-1, 72 weeks12.4% vs 0.9% placebo |
One receptor, two, or three
Your gut releases several hormones after a meal. The drugs differ in how many of them they imitate.
GLP-1 alone. The original approach. Reduces appetite, slows the stomach, prompts insulin. Liraglutide, semaglutide and orforglipron all stop here.
GLP-1 plus GIP. GIP is a second gut hormone with overlapping effects. Adding it produced noticeably more weight loss in trials than GLP-1 alone. Tirzepatide is the only approved example.
GLP-1, GIP and glucagon. Glucagon is the odd one out. It is best known for raising blood sugar, which sounds like the wrong direction entirely, but it also increases the rate at which the body burns energy. The theory is that the first two targets reduce how much you eat while the third increases how much you spend. Retatrutide is the furthest along. It is also the hardest to get right, because glucagon activity has to be balanced against its effect on blood sugar.
Two other combinations are in late-stage testing. Survodutide pairs GLP-1 with glucagon and skips GIP. CagriSema pairs semaglutide with cagrilintide, which imitates a fourth hormone called amylin. Neither is approved anywhere.
Where the EU and the UK have diverged
Since Brexit the United Kingdom licenses medicines separately from the European Union, and in this drug class the two have drifted apart. Most online comparisons are written for a United States audience and miss this completely.
| Molecule | European Union | United Kingdom | United States |
|---|---|---|---|
| Liraglutide | Authorised | Authorised | Authorised |
| Semaglutide, injected | Authorised | Authorised | Authorised |
| Semaglutide, tabletfor weight management | 15 Jul 2026 | 11 Jun 2026 | 22 Dec 2025 |
| Tirzepatide | Authorised | Authorised | Authorised |
| Orforglipron | Not authorised | 10 Aug 2026 | 1 Apr 2026 |
| Retatrutide | Not authorised | Not authorised | Not authorised |
| CagriSema | Not submitted | Not authorised | Under review |
| Survodutide | Not authorised | Not authorised | Not authorised |
Three things are worth pulling out of that table.
Orforglipron is the sharpest split. The UK authorised it on 10 August 2026 and said it was the first country in Europe to do so. The EU has not. There is a further twist: the UK approved it for both weight management and type 2 diabetes, while the United States approved it for weight management only. So the same tablet has three different legal statuses in three places.
The UK is running ahead on newer approvals. It cleared the semaglutide tablet about five weeks before the EU, and the higher-dose 7.2 mg injection roughly six months before. This is a change from the pre-Brexit pattern and is not something most reference sites have caught up with.
The United States is usually first. On both the semaglutide tablet and orforglipron, the FDA moved several months ahead of either European regulator. If you are reading American coverage, assume the European timeline is behind it.
Brand names, and one that will confuse you
The same molecule is sold under different names depending on the indication and the country. Semaglutide is Wegovy for weight and Ozempic for diabetes. Tirzepatide is Mounjaro in Europe for both, but in the United States it splits into Mounjaro for diabetes and Zepbound for weight. If you search Zepbound from Europe you will find a product that does not exist here. It is Mounjaro.
Why you cannot simply rank them by percentage
It is tempting to line the trials up and read off a winner. That comparison is weaker than it looks, for three reasons.
The participants differ. Starting weight, age, whether people with diabetes were included, and how much lifestyle support everyone received all vary between trials. Weight loss is consistently smaller in trials that include people with type 2 diabetes.
The trials differ in length. SCALE ran 56 weeks, STEP 1 ran 68, SURMOUNT-1 and ATTAIN-1 ran 72, TRIUMPH-1 ran 80. Longer trials generally show more loss, so part of any gap is just calendar.
The same trial reports two different numbers. This one causes real confusion, and understanding it will make you better informed than most of what you will read online.
The two-numbers problem
Every modern trial in this class reports its result twice. The efficacy estimand estimates the effect in people who actually stayed on the drug as intended. The treatment-regimen estimand includes everyone who started, whether they stopped early or not, and is always the lower figure.
Orforglipron is the clearest example. Its highest dose is quoted as either 12.4 percent or 11.2 percent. Both are correct. They are the two estimands from the same trial. Neither figure is a misprint and neither source is wrong. A page that quotes one without saying which is not giving you the full picture.
A head to head trial removes all of this by putting two drugs in the same study under the same rules. Very few exist in this class. Until they do, cross-trial comparisons are informed estimates, not measurements.
What is coming, and what to discount
Four molecules get written about as though they were nearly here. They are not, and their timelines differ a lot.
- Retatrutide (GLP-1, GIP, glucagon). Reported 28.3 percent average loss at 80 weeks in TRIUMPH-1. Eli Lilly signalled a United States filing in the first quarter of 2027, delayed from an earlier target. No European filing announced. Full status page.
- CagriSema (GLP-1 plus amylin). Reported 20.4 percent at 68 weeks in REDEFINE 1. Submitted in the United States in December 2025. Novo Nordisk has indicated it will wait for cardiovascular outcome data before approaching EU authorities, so Europe is likely well behind.
- Survodutide (GLP-1 plus glucagon). Reported up to 16.6 percent at 76 weeks. Not filed anywhere that we could verify.
- Mazdutide (GLP-1 plus glucagon). Approved in China in June 2025. Not approved and no verified filing in the EU, UK or US. For a European reader this is effectively a China-only product, despite appearing in a lot of English-language coverage.
Treat any specific European launch date you see for these as speculation, particularly on sites that also sell peptides. None of these four has an announced EMA filing.
Common questions
- Is the tablet as good as the injection?
For semaglutide the trial figures are broadly comparable, though the tablet must be taken on an empty stomach with strict timing rules. Orforglipron, the other tablet, produced less weight loss in its trial than injected semaglutide did in its own, but it has no food or timing restrictions at all. They are different trade-offs rather than a straight ranking.
- Is retatrutide really better than tirzepatide?
Its trial numbers are higher. No head to head study has been published, the trials differed in length and design, and retatrutide's side effect and discontinuation rates were also higher. The honest answer is that it looks stronger and that this has not been directly demonstrated.
- Why is "GLP-3" not a real thing?
It is an informal nickname for triple agonists, coined because they hit three receptors. There is no hormone called GLP-3 and no drug class by that name. You will mostly see it on retail sites.
Sources
- Pi-Sunyer X, Astrup A, Fujioka K, et al. SCALE Obesity and Prediabetes. New England Journal of Medicine, 2015. Percentage figures as stated in the FDA Saxenda label, section 14.1.
- Wilding JPH, et al. STEP 1. New England Journal of Medicine, 2021. DOI 10.1056/NEJMoa2032183.
- Jastreboff AM, Aronne LJ, Ahmad NN, et al. SURMOUNT-1. New England Journal of Medicine, 2022.
- ATTAIN-1 (orforglipron). New England Journal of Medicine, 2025. Efficacy estimand 12.4 percent, treatment-regimen estimand 11.2 percent.
- OASIS 4 (oral semaglutide 25 mg), Novo Nordisk regulatory releases, 2025 and 2026.
- Eli Lilly and Company, TRIUMPH-1 results, 21 May 2026.
- Novo Nordisk, REDEFINE 1 results and CagriSema regulatory submission, December 2025.
- MHRA, "UK first in Europe to authorise orforglipron for weight management and type 2 diabetes", 10 August 2026.
- European Commission and EMA authorisation records for Wegovy, Ozempic, Mounjaro, Rybelsus and Saxenda, checked 14 August 2026.
This page compares medicines on published trial and regulatory information. It is not medical advice, it does not recommend any product, and it deliberately contains no dosing guidance. Which medicine suits a given person is a decision for a doctor who knows their history.