Retatrutide vs Survodutide (2026): Triple vs GLP-1/Glucagon Dual Agonist Trial Data
Retatrutide vs survodutide: 28.3% at 80 weeks in TRIUMPH-1 vs 16.6% at 76 weeks in SYNCHRONIZE-1. See what adding GIP to GLP-1/glucagon agonism changes.
Research reference only. The information in this article is a summary of peer-reviewed scientific literature. It does not constitute medical advice and is not intended to guide human use. See our full disclaimer.
Retatrutide vs survodutide is the clearest test of what adding GIP receptor agonism to a GLP-1/glucagon backbone changes in published trial data. Both are once-weekly investigational peptides that activate the glucagon receptor (GCGR), and both now have Phase 3 obesity results: retatrutide (Eli Lilly) is a GIP/GLP-1/glucagon triple agonist evaluated in the TRIUMPH program, while survodutide (Boehringer Ingelheim and Zealand Pharma) is a GLP-1/glucagon dual agonist evaluated in the SYNCHRONIZE program.
Research reference only. All information on this page is a summary of peer-reviewed scientific literature and does not constitute medical advice. See individual library profiles for full compound data.
Quick Answer: Retatrutide and survodutide both activate the GLP-1 and glucagon receptors, but retatrutide also activates the GIP receptor. In Phase 3, retatrutide 12 mg reported 28.3% mean weight reduction at 80 weeks (TRIUMPH-1), while survodutide 6.0 mg reported 16.6% at 76 weeks (SYNCHRONIZE-1), both under the efficacy estimand; no head-to-head trial exists.
TL;DR:
- Retatrutide is a GIP/GLP-1/glucagon triple agonist; survodutide is a GLP-1/glucagon dual agonist.
- Phase 3 headline figures: 28.3% at 80 weeks (retatrutide 12 mg) vs 16.6% at 76 weeks (survodutide 6.0 mg).
- Survodutide has the deeper liver program, with FDA Breakthrough Therapy and EMA PRIME designations for MASH.
- Lilly plans a retatrutide BLA in Q1 2027; neither compound is approved by the FDA or EMA.
- Cross-trial comparisons are indirect because populations, durations and placebo responses differ.
| Feature | Retatrutide | Survodutide |
|---|---|---|
| Receptors | GIPR, GLP-1R, GCGR (triple) | GLP-1R, GCGR (dual) |
| Developer | Eli Lilly | Boehringer Ingelheim / Zealand Pharma |
| Most advanced stage | Phase 3 (TRIUMPH-1, -2, -3 reported) | Phase 3 (SYNCHRONIZE-1 reported) |
| Headline weight figure | −28.3% at 80 weeks, 12 mg (TRIUMPH-1) | −16.6% at 76 weeks, 6.0 mg (SYNCHRONIZE-1) |
| Placebo in that trial | −2.2% | −3.2% |
| Dosing interval | Once weekly, subcutaneous | Once weekly, subcutaneous |
Retatrutide: mechanism and evidence base
Retatrutide (LY3437943) is a single peptide engineered to activate three receptors: GIPR, GLP-1R and GCGR. In the published mechanism framing, GLP-1R agonism reduces food intake and slows gastric emptying, GIPR agonism contributes to appetite and adipose-tissue effects, and GCGR agonism raises energy expenditure and hepatic fat oxidation.
A 2026 preclinical study in Molecular Metabolism examined how much of that effect depends on the GLP-1 receptor. In diet-induced obese GLP-1R knockout mice, retatrutide still normalized body weight, which the authors attributed to the combined GIPR and GCGR components. The study concluded that "obesity can be reversed in the absence of a functional GLP-1R" (PMID 41997446). That finding is useful context for comparing retatrutide with survodutide, because the GIP arm is the main structural difference between them.
Clinically, the Phase 2 trial in adults with obesity reported mean weight reductions of up to 24.2% at 48 weeks (PMID 37366315). Phase 3 TRIUMPH-1 (NCT05929066) enrolled 2,339 adults with obesity or overweight without type 2 diabetes and reported −19.0%, −25.9% and −28.3% at 80 weeks for 4, 9 and 12 mg against −2.2% for placebo (efficacy estimand). TRIUMPH-2 in type 2 diabetes reported −20.8% at the 12 mg dose and was published in The Lancet in September 2026. The most common adverse events were gastrointestinal, and dysesthesia was reported in 5.1–12.5% of retatrutide recipients versus 0.9% with placebo in TRIUMPH-1.
Survodutide: mechanism and evidence base
Survodutide (BI 456906) is a once-weekly dual agonist of GCGR and GLP-1R. It belongs to the same oxyntomodulin-inspired class as mazdutide and pemvidutide, and is designed with relatively strong glucagon-receptor activity. Researchers frequently use it as the reference compound for studying how the glucagon arm affects liver fat and energy expenditure without GIP involvement.
A 46-week Phase 2 dose-finding trial in adults with a BMI of at least 27 kg/m² identified a dose-response relationship that informed Phase 3 dose selection (https://doi.org/10.1016/S2213-8587(23)00356-X). A separate 48-week Phase 2 trial in biopsy-confirmed MASH with F1–F3 fibrosis reported MASH improvement without worsening of fibrosis in up to 83% of survodutide-treated participants versus 18% with placebo (PMID 38847460).
The Phase 3 SYNCHRONIZE-1 trial enrolled adults with obesity or overweight without type 2 diabetes for 76 weeks; baseline characteristics were published in 2026 (PMID 41187967). Topline results released in April 2026 reported 15.3% (3.6 mg) and 16.6% (6.0 mg) mean weight reduction under the efficacy estimand, against 3.2% with placebo. Under the treatment-regimen estimand the figures were 12.2% and 13.0% against 5.4%. The 6.0 mg arm reported a 63.1% relative reduction in liver fat content.
Side-by-side comparison
| Parameter | Retatrutide | Survodutide |
|---|---|---|
| Class | GIP/GLP-1/glucagon triple agonist | GLP-1/glucagon dual agonist |
| Route | Subcutaneous | Subcutaneous |
| Interval | Once weekly | Once weekly |
| Phase 3 doses | 4, 9, 12 mg | 3.6, 6.0 mg |
| Phase 3 duration (obesity, no T2D) | 80 weeks | 76 weeks |
| Efficacy estimand, top dose | −28.3% | −16.6% |
| Treatment-regimen estimand, top dose | −25.0% | −13.0% |
| Liver program | Liver fat reductions reported in Phase 2 substudy | Phase 3 MASH program; Breakthrough Therapy, PRIME |
| Regulatory status | Investigational; BLA planned Q1 2027 | Investigational |
Half-life and pharmacokinetic data for once-weekly incretin-class peptides can be compared on the half-life chart.
Differential research applications
Isolating the GIP contribution. Because the two molecules share GLP-1R and GCGR activity, they are a natural pair for asking what GIPR agonism adds. The knockout-mouse work behind PMID 41997446 suggests GIPR and GCGR together can drive substantial weight reduction, which is why retatrutide is often discussed alongside tirzepatide (GIP/GLP-1) and survodutide (GLP-1/glucagon) as a three-way mechanism comparison.
Hepatic endpoints. Survodutide is the more common choice for MASH and fibrosis studies, given its biopsy-based Phase 2 data (PMID 38847460) and dedicated Phase 3 liver program. Retatrutide has reported large liver-fat reductions, but its pivotal program is organised around weight and cardiometabolic outcomes.
Magnitude of weight change. Researchers studying the upper bound of pharmacological weight reduction cite retatrutide's TRIUMPH data, where 45.3% of the 12 mg arm reached at least 30% weight loss in TRIUMPH-1. Survodutide's figures are closer to those of other dual agonists such as mazdutide.
Caution on indirect comparison. The headline numbers come from different trials with different durations (80 vs 76 weeks), placebo responses (−2.2% vs −3.2%) and dose ranges. Registered trials and status changes for both programs can be followed in the clinical trial tracker.
Regulatory and compounding status
| Authority | Retatrutide | Survodutide |
|---|---|---|
| FDA (US) | Not approved; investigational. Lilly plans BLA submission in Q1 2027 | Not approved; Breakthrough Therapy and Fast Track designations for MASH |
| EMA (EU) | Not approved | Not approved; PRIME designation for MASH |
| WADA | Not specifically named; investigational metabolic agents fall under the S0 non-approved substances category | Same S0 framing |
| 503A compounding | Not an approved drug component; not eligible | Listed as under review in our library data; not an approved drug component |
Neither peptide has an approved product label, so neither appears on FDA-approved drug listings. Research-grade material sold for laboratory use is not equivalent to a regulated pharmaceutical product.
Cited studies
- PMID 41997446, "GIPR:GCGR co-agonism restores normal weight in obese rodents" (Molecular Metabolism, 2026). https://doi.org/10.1016/j.molmet.2026.102365
- PMID 37366315, "Triple-Hormone-Receptor Agonist Retatrutide for Obesity, A Phase 2 Trial" (New England Journal of Medicine, 2023). https://doi.org/10.1056/NEJMoa2301972
- PMID 41187967, "Survodutide for treatment of obesity: Baseline characteristics of participants in a randomized, double-blind, placebo-controlled, phase 3 trial (SYNCHRONIZE-1)" (Diabetes, Obesity and Metabolism, 2026). https://doi.org/10.1111/dom.70196
- PMID 38847460, "A Phase 2 Randomized Trial of Survodutide in MASH and Fibrosis" (New England Journal of Medicine, 2024). https://doi.org/10.1056/NEJMoa2401755
- Survodutide Phase 2 obesity dose-finding trial (The Lancet Diabetes & Endocrinology, 2024). https://doi.org/10.1016/S2213-8587(23)00356-X
- ClinicalTrials.gov: TRIUMPH-1, NCT05929066.
Frequently asked questions
Q: What is the difference between retatrutide and survodutide?
A: Both activate the GLP-1 and glucagon receptors, but retatrutide also activates the GIP receptor, making it a triple agonist. Survodutide is a dual agonist developed by Boehringer Ingelheim and Zealand Pharma, while retatrutide is developed by Eli Lilly.
Q: Which produced more weight loss in trials, retatrutide or survodutide?
A: TRIUMPH-1 reported 28.3% mean weight reduction at 80 weeks with retatrutide 12 mg, and SYNCHRONIZE-1 reported 16.6% at 76 weeks with survodutide 6.0 mg, both under the efficacy estimand. The trials were run separately, so the figures are an indirect comparison.
Q: Is survodutide a GLP-1 agonist?
A: Survodutide activates the GLP-1 receptor, but it is classed as a GLP-1/glucagon dual agonist because it also activates the glucagon receptor. That glucagon activity is linked to its liver-fat and MASH research program.
Q: Why does glucagon receptor agonism matter in obesity research?
A: Glucagon receptor activation is associated with higher energy expenditure, hepatic fatty acid oxidation and reduced liver fat. Researchers study it as a complement to GLP-1-driven appetite reduction, which is why it appears in survodutide, mazdutide, pemvidutide and retatrutide.
Q: Are retatrutide or survodutide approved by the FDA?
A: Neither is approved by the FDA or EMA as of October 2026. Lilly has said it plans to submit a Biologics License Application for retatrutide in Q1 2027, and survodutide holds Breakthrough Therapy designation for MASH.
See also:
- Retatrutide Phase 3 results: TRIUMPH-1, -2 and -3: full dose tables and safety data from the retatrutide pivotal program
- Survodutide and the SYNCHRONIZE trials: overview of the survodutide Phase 3 program
- Mazdutide vs retatrutide: another dual-versus-triple agonist comparison
For laboratory research purposes only. Not for human or animal consumption. Compounds described are not approved by the FDA for human or veterinary use unless explicitly stated.