Ozempic vs retatrutide (Reta): the differences
Most people know semaglutide by its brand names, Ozempic and Wegovy. Retatrutide gets compared with it because it works on the same receptor and two more on top. Here you will find how the two differ, what their trials found, how the side effects compare and where each one stands with regulators. This is educational material only. RetaNord supplies retatrutide for laboratory research use.
| Ozempic / Wegovy | Retatrutide (Reta) | |
|---|---|---|
| Maker | Novo Nordisk | Eli Lilly |
| Active substance | Semaglutide | Retatrutide |
| Receptors | GLP-1 | GLP-1 + GIP + glucagon |
| Form | Weekly injection (Wegovy also as a daily pill) | Weekly injection (in trials) |
| Main obesity trial | STEP 1: −14.9% at 68 weeks with 2.4 mg (placebo −2.4%) | TRIUMPH-1: −28.3% at 80 weeks with 12 mg (placebo −2.2%) |
| Stopped because of side effects | 7% vs 3.1% placebo | 11.3% vs 4.9% placebo |
| Status | Approved medicines: Ozempic for type 2 diabetes, Wegovy for weight management | Investigational, not approved anywhere |
On this page
Is retatrutide the same as Ozempic?
No. They are different molecules from different companies. Ozempic is Novo Nordisk’s brand of semaglutide. Retatrutide is an Eli Lilly compound that has no brand name yet, and "Reta" is just a nickname. Both are weekly injections from the same family of gut-hormone compounds, but they work differently.
One receptor versus three
Semaglutide activates one receptor, GLP-1. GLP-1 slows the stomach and reduces appetite. Retatrutide activates GLP-1 too, plus two more: GIP, which adds to the effect on blood sugar and appetite, and glucagon, which raises the energy the body burns.
The glucagon part is the real difference. It makes the body burn more energy, which is the main reason researchers expected retatrutide to move body weight further than semaglutide.
What the trials showed
Semaglutide, STEP 1: adults with obesity or overweight lost on average 14.9% of their body weight after 68 weeks on 2.4 mg (the Wegovy dose), versus 2.4% on placebo.
Retatrutide, Phase 2: adults with obesity lost on average 24.2% after 48 weeks on 12 mg. Retatrutide, TRIUMPH-1 (Phase 3): adults with obesity or overweight without diabetes lost on average 28.3% after 80 weeks on 12 mg, versus 2.2% on placebo.
No trial has compared Ozempic and retatrutide directly. The closest thing is SURMOUNT-5, where tirzepatide (Mounjaro), which acts on two receptors, beat semaglutide head-to-head: −20.2% versus −13.7% at 72 weeks. More on that in Mounjaro vs Ozempic.
Which is stronger?
In the published trials, retatrutide came out well ahead: about 28% against about 15%. The catch is that the trials ran for different lengths of time, in different people, so read the gap as a direction rather than a precise ranking. And retatrutide is still investigational, so as a medicine there is nothing to compare it with yet.
Side effects compared
Both cause the typical side effects of this family, mostly nausea, diarrhoea, constipation and vomiting, usually while the dose is being raised. In STEP 1, 7% of people on semaglutide stopped because of side effects (3.1% on placebo). In TRIUMPH-1, 11.3% stopped on retatrutide 12 mg (4.9% on placebo).
The US label for Ozempic carries a boxed warning, the strongest kind the FDA uses: semaglutide caused thyroid C-cell tumours in rodents, and it is not known whether it does so in humans. Retatrutide’s long-term safety is still being studied in the TRIUMPH trials. See retatrutide side effects.
Approval status
Semaglutide is approved as Ozempic (type 2 diabetes), Wegovy (weight management, as an injection and, since 2026 in the EU, as a daily pill) and Rybelsus (type 2 diabetes, as a pill). Retatrutide is not approved anywhere; Lilly reported Phase 3 results in 2026. See is retatrutide approved?
The brand names, explained
Ozempic, Wegovy and Rybelsus all contain semaglutide (Novo Nordisk). Mounjaro and Zepbound contain tirzepatide (Eli Lilly). Foundayo contains orforglipron (Eli Lilly). Retatrutide has no brand name. If something is sold as "Ozempic" but does not come from Novo Nordisk, it is not Ozempic.
Sources
- Wilding et al. Once-weekly semaglutide in adults with overweight or obesity (STEP 1). N Engl J Med 2021
- Eli Lilly – Retatrutide TRIUMPH-1 topline results, 21 May 2026
- Jastreboff et al. Triple-hormone-receptor agonist retatrutide for obesity – a phase 2 trial. N Engl J Med 2023
- Aronne et al. Tirzepatide as compared with semaglutide for the treatment of obesity (SURMOUNT-5). N Engl J Med 2025
- US FDA – Ozempic (semaglutide) prescribing information, revised May 2026
Frequently asked questions
Is retatrutide the same as Ozempic?
No. Ozempic is a brand of semaglutide, an approved medicine that acts on one receptor (GLP-1). Retatrutide, often shortened to "Reta", is a different, investigational molecule from Eli Lilly that acts on three receptors: GLP-1, GIP and glucagon.
What is the difference between Ozempic and retatrutide?
Ozempic (semaglutide) acts on GLP-1 only and is an approved medicine. Retatrutide acts on GLP-1, GIP and glucagon and is still investigational. In their own trials, semaglutide 2.4 mg gave 14.9% weight loss at 68 weeks and retatrutide 12 mg gave 28.3% at 80 weeks.
Is retatrutide stronger than Ozempic?
In separate trials, retatrutide produced about twice the weight change: 28.3% at 80 weeks versus 14.9% at 68 weeks for semaglutide. No trial has compared them directly, and retatrutide is not an approved medicine.
Is retatrutide safer than Ozempic?
That cannot be said yet. Both cause similar stomach and gut side effects. In their trials, 11.3% stopped retatrutide 12 mg because of side effects (4.9% on placebo), and 7% stopped semaglutide 2.4 mg (3.1% on placebo). Retatrutide’s long-term safety is still being studied.
Is Ozempic a triple agonist?
No. Ozempic (semaglutide) is a single agonist: it acts on the GLP-1 receptor only. Tirzepatide (Mounjaro) is a dual agonist, and retatrutide is a triple agonist.
Is retatrutide approved like Ozempic?
No. Ozempic and Wegovy are approved medicines. Retatrutide is investigational and not approved anywhere. RetaNord supplies it for laboratory research use only.
What is the difference between Ozempic and Wegovy?
Both contain semaglutide from Novo Nordisk. Ozempic is approved for type 2 diabetes. Wegovy is approved for weight management, at a higher dose, as a weekly injection and also as a daily pill.