Survodutide vs Retatrutide

Dual vs triple: one glucagon arm, two blueprints

Both of these compounds belong to the modern incretin family, and both share the feature that made the newest generation of research peptides so interesting: agonism at the glucagon receptor, the "energy-out" arm that raises resting energy expenditure and mobilises hepatic fat. Where they part ways is in how many other receptors they recruit. Survodutide is a dual agonist — GLP-1 plus glucagon. Retatrutide is a triple agonist — GIP, GLP-1 and glucagon. The mechanistic detail behind each of those targets is unpacked in our explainer on GLP-1 vs GIP vs glucagon agonists; here we place the two molecules directly side by side.

Survodutide: the liver-focused dual agonist

Survodutide (developer code BI 456906) is a fatty-acid-conjugated long-acting peptide from Boehringer Ingelheim and Zealand Pharma, engineered as a balanced co-agonist of the GLP-1 and glucagon receptors. The design logic is a division of labour: the GLP-1 arm reduces energy intake — appetite suppression, slowed gastric emptying, glucose-dependent insulin release — while the glucagon arm increases energy expenditure and drives hepatic lipid mobilisation. Pairing the two lets the metabolic-rate and liver-fat benefits of glucagon signalling be captured while the insulinotropic GLP-1 arm offsets glucagon's tendency to raise blood glucose.

What sets Survodutide apart in the research literature is not weight loss alone but the liver. In a Phase 2 obesity dose-finding trial it produced up to roughly 19% mean body-weight reduction, but its standout result came in a Phase 2 MASH trial in biopsy-confirmed disease with fibrosis: improvement in MASH without worsening of fibrosis in a majority of participants on the mid dose versus a small fraction on placebo — data strong enough to earn FDA Breakthrough Therapy designation for MASH. That hepatic profile is why Survodutide is one of the most closely watched research compounds for fatty-liver disease. Its fatty-acid conjugation drives reversible albumin binding, giving it a long, once-weekly duration of action. It remains investigational — supplied only as a research reagent, not an approved medicine. Researchers can buy Survodutide UK from RS Bio Labs in three strengths at ≥99% purity with a COA; the full Survodutide knowledgebase profile covers the trial data in depth.

Retatrutide: the triple agonist

Retatrutide (developer code LY3437943) is Eli Lilly's first-in-class triple agonist, a 39-amino-acid peptide of roughly 4,731 Da that layers a third target — GIP — on top of GLP-1 and glucagon. Like Survodutide it carries a C20 fatty-acid tail for albumin binding, giving it a terminal half-life of about six days and a once-weekly research schedule. The GLP-1 and GIP arms lower energy intake; the glucagon arm raises energy expenditure. No dual agonist engages all three at once, and that "energy-in, energy-out" breadth is what researchers credit for the magnitude of its effect.

In the Phase 2 TRIUMPH-1 obesity trial Retatrutide posted up to roughly 24.2% mean body-weight reduction at 48 weeks — the largest figure reported for any incretin-class compound, and one that had not plateaued when the trial period ended. It also carries its own liver credentials: in a Phase 2a MASLD study it reduced hepatic fat by around 80% at the higher doses. Retatrutide is investigational and in Phase 3 development, supplied strictly as a research reagent. RS Bio Labs stocks eight strengths (5–60 mg); see the Retatrutide knowledgebase profile for the full evidence base, or the page to buy Retatrutide research material directly.

What the differences mean in a research context

The cleanest way to read this pairing is as a controlled contrast in receptor count. Both molecules share the glucagon arm, so both carry the metabolic-rate and hepatic-lipid signature that arm produces. The variable is GIP: Survodutide leaves it out, Retatrutide adds it. In cross-trial terms, the triple agonist reports the larger weight-loss numbers — consistent with the broader pattern that adding complementary receptors has raised the ceiling on effect size at each step of the incretin ladder.

But effect size is not the whole story, and the two compounds are not really competing for the same research question. Survodutide's centre of gravity is the liver — its MASH and fibrosis data, and the Breakthrough Therapy designation that followed, define its profile. Retatrutide's is broad metabolic effect — obesity, type 2 diabetes and liver fat, with weight loss as the headline. A researcher interested in steatohepatitis histology and a researcher interested in maximal metabolic response are looking at different lead endpoints, even though both molecules touch the glucagon receptor.

The usual caveat applies: these headline figures come from separate trials with different populations, durations and protocols, so the percentages describe a trend rather than a controlled head-to-head. Both remain investigational, and both should be handled purely as in vitro research reagents. For how the glucagon-containing duals sit against the wider field, our Semaglutide vs Tirzepatide vs Retatrutide comparison maps the full ladder.

The bottom line

Survodutide and Retatrutide both harness the glucagon "energy-out" arm, but they are built for different jobs. Survodutide pairs it with GLP-1 as a dual agonist optimised around liver research; Retatrutide adds GIP as a triple agonist optimised around broad metabolic effect and the biggest weight-loss numbers in the class. Choose by the research question, not the headline percentage. For research-grade material, see our dedicated pages to buy Survodutide UK and buy Retatrutide UK, each ≥99% purity with a COA.