Liraglutide vs Retatrutide
A neutral, side-by-side comparison of two glp-1 & metabolic peptides — their mechanisms, dosing ranges, administration routes, side effects, and research evidence. For research and educational purposes only.
Liraglutide
Liraglutide is a once-daily GLP-1 receptor agonist — the first long-acting GLP-1 analog approved for both type 2 diabetes (Victoza, 1.8mg) and chronic weight management (Saxenda, 3mg). It was the foundational GLP-1 agonist that established the class's cardiovascular benefits and set the stage for semaglutide and tirzepatide.
Full profileRetatrutide
Retatrutide (LY3437943) is Eli Lilly's investigational once-weekly triple agonist of the GIP, GLP-1, and glucagon receptors. Phase 2 data showed 24.2% mean weight loss at 48 weeks; the Phase 3 TRIUMPH program has since reported topline weight loss approaching 28–30% — among the largest reductions recorded for any obesity pharmacotherapy. It is not yet FDA-approved.
Full profile| Liraglutide | Retatrutide | |
|---|---|---|
| Category | GLP-1 & Metabolic | GLP-1 & Metabolic |
| Also known as | NN2211, Victoza, Saxenda | LY3437943, Triple G, GIP/GLP-1/Glucagon Receptor Agonist |
| Evidence | FDA-approved | Investigational (in trials) |
| Dosing range | 0.6mg–3.0mg mg, Once daily subcutaneous injection | 2mg–12mg mg, once weekly |
| Administration | Subcutaneous injection (abdomen, thigh, or upper arm) | Subcutaneous injection (weekly) |
| Key side effects | Nausea (most common, especially during initiation), Vomiting, Diarrhea, Decreased appetite | Nausea (most common, dose-dependent), Vomiting, Diarrhea, Constipation |
| Cited sources | 2 references | 6 references |
Key differences
- Evidence level differs: Liraglutide is fda-approved, while Retatrutide is investigational (in trials).
- Administration: Liraglutide — Subcutaneous injection (abdomen, thigh, or upper arm); Retatrutide — Subcutaneous injection (weekly).
- Frequency: Liraglutide is typically Once daily subcutaneous injection; Retatrutide is once weekly.
- Research depth: this profile cites 2 sources for Liraglutide vs 6 for Retatrutide.
How each works
Liraglutide
The LEADER trial (N=9340) demonstrated significant reduction in major adverse cardiovascular events (MACE) in high-risk T2D patients — the first cardiovascular outcomes trial for a GLP-1 agonist. The SCALE trials showed 5–8% mean weight loss at 3mg/day vs placebo. While superseded by semaglutide and tirzepatide in weight loss efficacy, liraglutide has the longest safety record in the class (approved 2010) and daily dosing allows finer tolerability titration.
Retatrutide
Across the Phase 2 trial (NEJM 2023, Jastreboff et al.) and the Phase 3 TRIUMPH registrational program (TRIUMPH-1 through -4), retatrutide has produced dose-dependent weight loss reaching ~28.3% at 80 weeks (TRIUMPH-1, 12 mg) and ~28.7% at 68 weeks in a knee-osteoarthritis population (TRIUMPH-4, 12 mg), alongside improvements in glycemia, blood pressure, lipids, and liver fat. The glucagon component is thought to add energy expenditure on top of the appetite suppression driven by GLP-1 and GIP. As of mid-2026, Phase 3 efficacy figures are topline (press-release/conference level) and not yet published in full peer-reviewed form.
This comparison aggregates public research and structured profile data for informational purposes only. It is not medical advice and does not recommend either compound for human use. Consult a qualified healthcare provider before considering any peptide.