Retatrutide or Ozempic: Comparing the Published Evidence
Semaglutide, the active molecule in Ozempic and Wegovy, made GLP-1 agonists widely known outside medicine. Retatrutide is increasingly labelled the “next generation”. The reason is simple: it engages three receptors instead of one. Here we compare the two on how they act and on the weight-change results their clinical trials reported.
This page is educational and draws on published studies. Retatrutide is an investigational compound. NordPeps supplies it for laboratory research use only.
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A single target versus three
Semaglutide acts on one receptor only, the GLP-1 receptor. Retatrutide is a triple agonist. It engages the GLP-1, GIP and glucagon receptors together. The added GIP and glucagon activity is the design feature behind expectations of a bigger metabolic effect. Glucagon-receptor activation, in particular, is linked with higher energy expenditure. That sits on top of the appetite and fullness effects common to every GLP-1-class compound.
Put simply: Ozempic works through one metabolic pathway, and retatrutide works through three.
Reported weight change
Each figure below comes from a different trial. None is a head-to-head result. The pattern, however, points the same way:
- Retatrutide ≈ 24.2%: mean fall in body weight after 48 weeks on 12 mg, from a Phase 2 trial published in the New England Journal of Medicine in 2023.
- Tirzepatide ≈ 20.9%: after 72 weeks on 15 mg in SURMOUNT-1 (2022). Tirzepatide is a dual GIP/GLP-1 agonist.
- Semaglutide ≈ 14.9%: after 68 weeks on 2.4 mg in STEP-1 (2021).
Tirzepatide as the middle step
Tirzepatide, the active molecule in Mounjaro and Zepbound, sits between the other two. It is a dual GIP/GLP-1 agonist. Its trial result of about 21% lies between semaglutide's single-agonist figure and retatrutide's triple-agonist figure. Researchers partly for this reason see the move from one receptor to two to three as a steady line of progress.
Regulatory status and the research-use label
Semaglutide and tirzepatide are licensed medicines. Retatrutide is investigational. It is in late-stage clinical trials and has no approval as a drug. NordPeps sells retatrutide purely as research-grade material, intended for in vitro and laboratory work. It is not for use in humans or animals. The names Ozempic and Wegovy belong to Novo Nordisk, and Mounjaro and Zepbound to Eli Lilly; all four are registered trademarks. NordPeps is an independent company, with no affiliation to or endorsement from either.
NordPeps retatrutide
NordPeps offers retatrutide as a 10 mg lyophilized vial. Certificates from an independent third-party laboratory are published per batch on /certificates as they become available. The price is €84.95, with free EU shipping on orders from €200. For laboratory research use only. The product page also has a side-by-side comparison table.
Frequently asked questions
Does retatrutide outperform Ozempic?
Each compound was tested in its own trials. Retatrutide's showed the larger mean weight reduction, about 24% against about 15% for semaglutide, and it engages three receptors instead of one. The trials were designed differently, though, and retatrutide is still investigational with no approval. So this is neither a like-for-like nor a regulatory comparison.
How do Ozempic and retatrutide differ?
Ozempic's active ingredient is semaglutide, which acts on the GLP-1 receptor alone. Retatrutide acts on three receptors: GLP-1, GIP and glucagon. The extra GIP and glucagon activity is why researchers call it a next-generation compound.
Can retatrutide be prescribed like Ozempic?
No. In 2026 retatrutide is an investigational compound in late-stage trials, not an approved or prescription drug. NordPeps supplies it for laboratory research use only.
What is the point of acting on three receptors?
GLP-1 drives the appetite and fullness effects. GIP contributes additional metabolic signalling. Glucagon-receptor activation is linked with higher energy expenditure. Together they explain the rationale for the bigger weight changes seen in retatrutide trials.