Description
Retatrutide | Triple GIP/GLP-1/Glucagon Receptor Agonist — Research Grade
Retatrutide (LY3437943) is an investigational once-weekly injectable triple receptor agonist simultaneously targeting GIP (glucose-dependent insulinotropic polypeptide), GLP-1 (glucagon-like peptide-1), and glucagon receptors. Developed by Eli Lilly, it is in Phase III clinical trials and represents the leading edge of incretin-based obesity pharmacology.
Mechanism of Action
- GLP-1R agonism — reduces appetite, delays gastric emptying, stimulates glucose-dependent insulin secretion
- GIPR agonism — synergistic with GLP-1 for weight reduction; modulates adipose tissue GIP signalling
- Glucagon receptor agonism — increases energy expenditure and hepatic fat oxidation, differentiating Retatrutide from dual GIP/GLP-1 agonists
- Additive efficacy — triple mechanism achieves weight loss beyond tirzepatide in comparative Phase II data
Research Areas
Phase II dose-ranging trial (n=338, 48 weeks) reported 24.2% mean body weight reduction at highest dose — exceeding any prior injectable compound in clinical history. Phase III trials in obesity and type 2 diabetes are ongoing. Also studied in NASH, heart failure, and sleep apnoea.
For Research Use Only. Rainbow Peptide supplies Retatrutide exclusively for in vitro and laboratory research purposes. Not for human or veterinary use.






Dr. C. Walsh –
Retatrutide used in our GLP-1/GIP/glucagon triple agonist research. Lot verified at >99% purity by reverse-phase HPLC — above spec. Mass spec confirmed molecular weight exactly. Best peptide supplier we’ve used for metabolic research.
I. Blackwood –
High-purity Retatrutide for our incretin receptor panel study. Rainbow Peptide’s COA matched our LC-MS results exactly. In vitro receptor activation data was clean and reproducible across two lots. Will continue ordering.
Y. Tanaka –
Retatrutide is one of the hardest peptides to source at high purity. Rainbow Peptide delivered >99% confirmed. Our triple agonist binding assay showed expected relative potency ratios. Outstanding quality.