Retatrutide vs Semaglutide
Semaglutide is the most-published GLP-1 receptor agonist in research literature, marketed as Ozempic, Wegovy and Rybelsus. Retatrutide is an investigational triple agonist that activates GLP-1, GIP and glucagon receptors in a single molecule. This page compares the two as research compounds.
| Retatrutide | Semaglutide | |
|---|---|---|
| Developmental code | LY3437943 | Semaglutide (NN9535) |
| Receptor targets | GLP-1, GIP, glucagon (triple) | GLP-1 (selective) |
| Approval status | Phase 3, investigational only | Approved as Ozempic, Wegovy, Rybelsus |
| Phase 2 / 3 body-weight reduction | 24.2% at 48 weeks (phase 2) | 14.9% at 68 weeks (STEP-1) |
| Administration frequency | Once weekly | Once weekly (injectable) or daily oral |
| Peptx dose sizes | 10mg to 60mg vials | 5mg to 30mg vials |
The selectivity question, single target vs triple
Semaglutide is a selective GLP-1 receptor agonist with no meaningful activity at GIP or glucagon receptors. Its mechanism is well-characterised and the published literature stretches back over a decade, covering everything from rodent satiety models through human cardiovascular outcomes trials.
Retatrutide takes the opposite approach, activating three receptors at once to produce additive metabolic effects. The trade-off is that triple agonism produces effects on energy expenditure, hepatic lipid handling and adipose tissue that selective GLP-1 agonism does not, but the broader pharmacology also means a wider safety profile to characterise.
Published efficacy data
Semaglutide's STEP-1 trial reported 14.9% mean body-weight reduction at the 2.4mg weekly dose over 68 weeks. The CVOT (cardiovascular outcomes trial) SUSTAIN-6 also established a meaningful reduction in major adverse cardiovascular events, which is the cardio-metabolic gold-standard endpoint.
Retatrutide's phase 2 TRIUMPH-1 reported 24.2% mean body-weight reduction at the 12mg weekly dose over 48 weeks, with the dose-response curve still climbing at trial end. No long-term outcomes data exists yet because the compound is still pre-approval.
Research utility
Semaglutide is the canonical reference compound for any GLP-1 selective receptor study. If a research protocol needs a benchmark against published human and animal efficacy data, Semaglutide is the most-cited choice in the literature.
Retatrutide is the natural reference compound for any study probing the additive effects of multi-receptor incretin agonism. As triple-target therapeutics become more common across the metabolic and cardiovascular space, Retatrutide will likely become the standard reference for that class.
Bottom line for research labs
For any research project benchmarking against the broader peer-reviewed literature, Semaglutide is the default choice because the citation base is enormous. For research probing next-generation multi-receptor pharmacology, Retatrutide is the more interesting target.