Retatrutide is an investigational once-weekly injectable peptide from Eli Lilly: a “triple agonist” that activates the GIP, GLP-1, and glucagon receptors at once. It is not an approved medicine anywhere; it exists in late-stage clinical trials and, separately, in a research-chemical gray market that this index tracks.
Most weight-loss peptides in this class hit one receptor (semaglutide) or two (tirzepatide). Retatrutide adds a third, the glucagon receptor, which is believed to raise energy expenditure on top of the appetite-suppression effects of GIP/GLP-1 signaling. That three-receptor profile is why its trial numbers drew so much attention.
In the phase 2 obesity trial (NEJM, 2023), the 12 mg weekly group averaged a 24.2% weight reduction at 48 weeks. The first phase 3 results (TRIUMPH-1, May 2026) reported −25.0% at 80 weeks on 12 mg, reaching −30.3% in the 104-week extension with no plateau observed (Lilly). Full dose-by-dose data: our retatrutide dosage guide.
Not FDA-approved, no legal pharmacy route, and no legal compounded version: the FDA has sent warning letters to companies selling compounded retatrutide. The gray market sells it “for research use only.” Details and vendor-evaluation checks: where to buy retatrutide.
Working out reconstitution or syringe units? Use the free peptide calculator, then check your batch’s published test result before trusting the label: in 2024, roughly 43% of research peptides submitted to Janoshik Analytical missed their label claims.
Vendor rankings on PeptideCensus are computed only from publicly published third-party lab results; see the vendor index and how scoring works.
Gastrointestinal events (nausea, vomiting, diarrhea) were the most common adverse events in published trials: dose-related, mostly mild to moderate, and partially mitigated by the lower 2 mg starting dose. Gray-market vials add a second risk layer the trials never had: unverified contents.
No. It is investigational, in phase 3 trials (the TRIUMPH program). Any approval date you read is speculation.
Partly: it agonizes the GLP-1 receptor plus the GIP and glucagon receptors, which is why it is often called a “triple G” agonist.
Tirzepatide hits two receptors (GIP/GLP-1); retatrutide adds glucagon. Trial-reported weight reduction on retatrutide’s top dose exceeded tirzepatide’s published figures, but they have never been compared head-to-head in one trial.
Prices vary several-fold per milligram between vendors; compare price per tested milligram on the vendor index, not per vial.
PeptideCensus aggregates publicly published third-party lab results and links every number to its source. Nothing on this page is medical advice; research compounds are not for human use.