Retatrutide is a synthetic 39-amino-acid peptide that activates three hormone receptors at once: GIP, GLP-1 and glucagon. A C20 fatty diacid attached to one lysine lets it bind albumin, which is why researchers call it a long-acting triple agonist, and why it is nicknamed reta (GLP-3).
This reference collects what a laboratory needs to know about reta as a material: how its sequence behaves in the vial, what it dissolves in, how it is handled at the bench and what to do when an order arrives. Each section below has its own page.
Molecular reference
| Name | Retatrutide |
|---|---|
| Also known as | Reta, reta (GLP-3), Triple G |
| Sequence | Tyr-Aib-Gln-Gly-Thr-Phe-Thr-Ser-Asp-Tyr-Ser-Ile-αMeLeu-Leu-Asp-Lys-Lys(C20 diacid-γGlu-AEEA)-Ala-Gln-Aib-Ala-Phe-Ile-Glu-Tyr-Leu-Leu-Glu-Gly-Gly-Pro-Ser-Ser-Gly-Ala-Pro-Pro-Pro-Ser-NH2 |
| Residues | 39 |
| Molecular formula | C221H342N46O68 |
| Molecular weight | 4731 g/mol |
| CAS number | 2381089-83-2 |
Four features of that sequence explain most of its behaviour. Three residues are not among the twenty coded amino acids: aminoisobutyric acid (Aib) at positions 2 and 20 and an alpha-methyl leucine at position 13. These alpha-methylated residues favour a helical backbone and resist enzymes that clip the second residue of incretin peptides, a design principle shared with other long-acting analogues (Lau et al., J Med Chem, 2015). The lysine at position 17 carries a C20 fatty diacid joined through a gamma-glutamic acid and a short AEEA linker, which makes the molecule amphiphilic. The sequence has no methionine, cysteine, tryptophan, histidine or asparagine, so the fastest oxidation and deamidation routes are absent (Manning et al., Pharm Res, 2010). And the C-terminal tail, Gly-Gly-Pro-Ser-Ser-Gly-Ala-Pro-Pro-Pro-Ser, is proline-rich and flexible, ending in an amide.
What it is studied for
Reta was designed to combine the appetite and insulin effects of GIP and GLP-1 signalling with the energy-expenditure effect of glucagon signalling. In an animal model of obesity it lowered body weight and improved glycaemic control, and the added glucagon activity increased energy expenditure beyond what the two incretin signals produced alone (Coskun et al., Cell Metab, 2022).
In human research the findings have been large. In a 48-week phase 2 obesity trial, mean body weight fell by up to 24.2% in the top treatment arm against 2.1% with placebo (Jastreboff et al., N Engl J Med, 2023), and a phase 3 obesity trial reported reductions of up to 25.0% at 80 weeks (Jastreboff et al., N Engl J Med, 2026). In type 2 diabetes, HbA1c fell by up to 2.02 percentage points at 24 weeks (Rosenstock et al., Lancet, 2023). In a liver substudy, 86% of participants in the top treatment arm reached normal liver fat by 24 weeks (Sanyal et al., Nat Med, 2024). Gastrointestinal effects were the most common adverse events in these trials and were mostly mild to moderate.
More on the trial record is in reta weight-loss trials, reta and fatty liver and what is reta (GLP-3).
The sections of this reference
Stability. Without the most reactive residues, reta’s main chemical weak points are its two glutamines, two aspartates and three tyrosines, while its lipid chain makes physical aggregation the bigger concern in solution. Reta stability explains each route and how cold, dark storage slows it.
Solubility. Reta carries a net negative charge at neutral pH, which shapes what it dissolves in and why acidic diluents work against it. Reta solubility covers bacteriostatic water, saline, concentration and the causes of haze.
Handling. Temperature equilibration, gentle swirling, aseptic access and clear labelling matter more for an amphiphilic peptide than for a small, plain one. Reta handling lists the bench practice and the common mistakes.
On arrival. What a sealed vial of lyophilised reta should look like and what to do with it first is in reta on arrival.
FAQ. Short answers to the questions researchers ask most about storing, mixing and keeping reta are in the reta FAQ.
Storage and reconstitution. Storage windows for powder and mixed solution are in how long does reta last, and water volumes and concentrations for each vial size are in the reta reconstitution calculator.
Reta at Vistara Labs
Vistara Labs supplies reta (GLP-3) as lyophilised vials for laboratory research, shipped within Canada by Canada Post Xpresspost. Certificates are on the lab reports page, and the reta buying guide for Canada covers sourcing in more detail.
All products supplied by Vistara Labs are intended for laboratory research use only. They are not drugs, are not approved for human or veterinary use, and are not intended to diagnose, treat, cure or prevent any condition. Nothing on this page constitutes medical advice or guidance for use in humans.
