Retatrutide
Retatrutide is a long-acting, unimolecular peptide engineered to activate the GIP, GLP-1, and glucagon receptors simultaneously. Its triple-agonist mechanism has made it a focal point of recent metabolic research, particularly studies examining energy expenditure, glycemic control, and body-composition outcomes.
Part of KYIN Peptides' standard catalogue — see the product page for pricing and available sizes.
What Is Retatrutide?
Retatrutide came out of Eli Lilly's incretin-biology research group — the same program responsible for tirzepatide. Where earlier compounds in this line activated one or two hormone receptors (GLP-1 alone, or GLP-1 and GIP together), Lilly's researchers designed Retatrutide as a single molecule capable of activating three receptors at once: GIP, GLP-1, and glucagon. Adding glucagon receptor activity on top of the two incretin pathways was a deliberate design choice, intended to add glucagon's own energy-expenditure and hepatic lipid-oxidation effects to the compound's profile.
Research Focus
Retatrutide's research profile is defined by its triple-receptor mechanism, and most published and ongoing research reflects that starting point directly. It sits in KYIN's Weight Loss / Metabolic category alongside Tirzepatide, a fellow incretin-receptor agonist, and 5-Amino-1MQ, an NNMT inhibitor with an entirely different mechanism. See our Weight Loss / Metabolic research overview for how Retatrutide compares to Semaglutide, Tirzepatide, and 5-Amino-1MQ.
- Triple-receptor (GIP/GLP-1/glucagon) agonism research
- Energy expenditure and metabolic rate studies
- Glycemic control research
- Body composition research models
Clinical & Preclinical Trial Data
The landmark preclinical paper, led by Coskun and colleagues, was published in Cell Metabolism in September 2022, and first-in-human research followed shortly after. A Phase 2 trial published in the New England Journal of Medicine in 2023 reported mean weight loss of up to 24.2% at 48 weeks in participants with obesity, and 16.9% at 36 weeks in a separate trial in participants with type 2 diabetes — the first published Phase 2 data for any triple GLP-1/GIP/glucagon agonist. The Phase 3 TRIUMPH-1 trial (2,339 adults with obesity or overweight and at least one weight-related condition, without type 2 diabetes) reported a mean weight loss of 28.3% at the 12mg dose over 80 weeks, with 45.3% of participants losing at least 30% of body weight — a threshold historically associated with bariatric surgery. A study extension in participants with baseline BMI ≥35 reached an average of 30.3% weight loss at 104 weeks, and all three doses tested (4mg, 9mg, 12mg) met their primary and key secondary endpoints against placebo.
Two further Phase 3 readouts followed in 2026. The TRIUMPH-2 trial (1,152 adults with obesity and type 2 diabetes), published in The Lancet and presented at the EASD Annual Meeting in Milan in late September 2026, reported mean weight loss of 20.8% alongside an A1C reduction of up to 1.6% at the 12mg dose over 80 weeks, with 59.5% of participants on that dose no longer meeting the BMI criteria for obesity by the study's end. The TRIUMPH-3 trial (adults with severe obesity and established cardiovascular disease) reported 22.6% mean weight loss at 80 weeks alongside a 37% reduction in triglycerides and a 51% reduction in hsCRP, though as of this writing only topline results have been announced and the full data has not yet been peer-reviewed or published. Lilly has stated it plans to submit a Biologics License Application to the FDA in Q1 2027. As of this writing, Retatrutide remains investigational across all these indications and has not received regulatory approval anywhere; it is not an approved drug.
Explore the Full Retatrutide Research Cluster
Every angle of Retatrutide research in one place:
- Mechanism of Action — how triple GIP/GLP-1/glucagon receptor agonism works
- Discovery & Research History — how Retatrutide was engineered and its path through clinical trials
- Semaglutide vs Tirzepatide vs Retatrutide — how the GLP-1 drug class compares
- Cagrilintide vs Retatrutide — amylin-receptor vs triple-receptor mechanisms
- Retatrutide vs MOTS-c — receptor agonism vs mitochondrial signaling
- Retatrutide vs 5-Amino-1MQ — receptor agonism vs NNMT enzyme inhibition
- Certificate of Analysis Guide — how to read Retatrutide's purity testing
- Product & Pricing
Availability
Retatrutide is part of KYIN Peptides' standard catalogue — see the product page for pricing and available sizes, or contact us to order.
Retatrutide questions
What is Retatrutide?
Retatrutide is a long-acting, unimolecular peptide engineered by Eli Lilly's incretin-biology research group to activate the GIP, GLP-1, and glucagon receptors simultaneously — a triple-agonist mechanism studied in metabolic research for its effects on energy expenditure, glycemic control, and body composition.
Has Retatrutide been tested in human trials?
Yes. A Phase 2 trial published in the New England Journal of Medicine in 2023 reported mean weight loss of up to 24.2% at 48 weeks in participants with obesity. The Phase 3 TRIUMPH-1 trial (2,339 adults) reported 28.3% mean weight loss at the 12mg dose over 80 weeks, with 45.3% of participants losing at least 30% of body weight. Two further Phase 3 trials reported results in 2026: TRIUMPH-2 (published in The Lancet) found 20.8% mean weight loss and up to 1.6% A1C reduction in adults with type 2 diabetes, and TRIUMPH-3 reported 22.6% mean weight loss in adults with cardiovascular disease, though TRIUMPH-3's full results are not yet peer-reviewed. Retatrutide remains investigational and has not received regulatory approval anywhere.
Does KYIN Peptides sell Retatrutide?
Yes — Retatrutide is part of our standard catalogue. See the product page for pricing and available sizes.
Interested in Retatrutide?
See pricing and order on the product page, or browse our other weight-loss and metabolic peptides.