Retatrutide: Structure, Research Overview and Specifications
Retatrutide (LY3437943) is an investigational synthetic peptide that acts as an agonist at three receptors involved in metabolic regulation: GIP, GLP-1 and glucagon. It is one of the most closely followed compounds in incretin research. This page summarises its structure, mechanism, published research and the specifications of the material we supply.
For in vitro research use only. Not for human or animal use. Nothing on this page is medical advice.
What is retatrutide?
Retatrutide is a single synthetic peptide engineered to activate three receptors that normally respond to separate gut and pancreatic hormones: the glucose-dependent insulinotropic polypeptide receptor (GIPR), the glucagon-like peptide-1 receptor (GLP-1R) and the glucagon receptor (GCGR). Because all three receptor names begin with G, it is often described as a “triple G” agonist.
It was developed by Eli Lilly and Company and builds on earlier single (GLP-1) and dual (GIP/GLP-1) agonist research. In the laboratory it is used to study how combined incretin and glucagon signalling affects energy balance, lipid metabolism and liver fat.
Chemical data
| Name | Retatrutide (LY3437943) |
|---|---|
| Class | Synthetic peptide, triple agonist of GIP, GLP-1 and glucagon receptors |
| Structure | 39-amino-acid peptide containing non-standard residues (Aib, α-methyl-leucine), with a C20 fatty diacid attached to a lysine side chain via a linker to support albumin binding |
| Molecular formula | C221H342N46O68 |
| Molecular weight | ≈ 4731 g/mol |
| CAS number | 2381089-83-2 |
| Appearance | White lyophilised powder |
| Available sizes | 10mg · 20mg · 40mg |
Available sizes
Mechanism of action
- GLP-1 receptor. GLP-1 signalling is studied for its effects on glucose-dependent insulin secretion, gastric emptying and appetite-related pathways.
- GIP receptor. GIP is the other major incretin hormone. Combined GIP/GLP-1 agonism is the basis of the dual-agonist class.
- Glucagon receptor. Glucagon-receptor activity is investigated for effects on energy expenditure, hepatic lipid metabolism and liver fat.
- Extended half-life. The fatty-acid modification promotes reversible binding to albumin, prolonging circulation compared with native hormones.
What the published research shows
Phase 2 obesity trial
A 48-week, randomised, placebo-controlled phase 2 trial published in the New England Journal of Medicine (Jastreboff et al., 2023) studied retatrutide in adults with obesity or overweight. It reported dose-dependent reductions in body weight, with mean reductions of more than 24% at 48 weeks in the highest-dose group, compared with around 2% with placebo.
Liver fat
A randomised phase 2a sub-study published in Nature Medicine (2024) examined retatrutide in metabolic dysfunction-associated steatotic liver disease (MASLD) and reported substantial reductions in liver fat content over the study period.
Phase 3 programme
Retatrutide is being evaluated in the phase 3 TRIUMPH programme of clinical trials in obesity and related conditions. Until these trials are completed and reviewed by regulators, its long-term efficacy and safety profile remain under investigation.
Limitations of the evidence
- Published efficacy data come mainly from phase 2 trials of limited size and duration.
- Gastrointestinal adverse events and increases in heart rate were reported in trials, as seen with other incretin-based agents.
- Long-term outcomes, including cardiovascular outcomes, are still being studied in phase 3.
- Clinical findings were obtained with pharmaceutical-grade material under medical supervision and do not apply to research-grade reagents.
Regulatory status
Retatrutide is an investigational compound. It is not a licensed medicine in the UK and has not been approved by the MHRA, FDA or EMA. Sterling Research supplies retatrutide only as a research reagent for in vitro laboratory use. It must not be used in humans or animals.
Storage and handling in the lab
- Store lyophilised powder at −20 °C, sealed and protected from light and moisture.
- Let the vial reach room temperature before opening to limit condensation.
- Prepare solutions to your laboratory’s validated protocols, with appropriate PPE and aseptic technique.
- Lipidated peptides can adsorb to plastics. Follow your protocol for buffer choice and low-binding labware.
Quality
Every batch of retatrutide we supply is independently tested by Janoshik for purity and identity before it is released for sale.
Related research compounds
Frequently asked questions
What is retatrutide?
Retatrutide (LY3437943) is an investigational synthetic peptide developed by Eli Lilly that acts as an agonist at three receptors: GIP, GLP-1 and glucagon.
How is retatrutide different from tirzepatide?
Tirzepatide is a dual GIP and GLP-1 receptor agonist. Retatrutide adds glucagon-receptor agonism, which is why it is described as a triple agonist.
Is retatrutide approved in the UK?
No. Retatrutide is an investigational compound. It is not a licensed medicine in the UK and has not been approved by the MHRA, FDA or EMA.
Why is retatrutide sometimes called a “triple G” agonist?
Because the three receptors it targets (GIP, GLP-1 and glucagon) all begin with G, retatrutide is often described as a “triple G” agonist in the literature.
Which sizes does Sterling supply?
Retatrutide is supplied as lyophilised research material in 10mg, 20mg and 40mg vials, for in vitro laboratory use only.
References
- Jastreboff AM, et al. Triple–Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial. N Engl J Med. 2023;389:514–526. doi:10.1056/NEJMoa2301972
- Triple hormone receptor agonist retatrutide for metabolic dysfunction-associated steatotic liver disease: a randomized phase 2a trial. Nat Med. 2024. PubMed 38858523
- Triple G Agonists — A Home Run for Obesity? N Engl J Med. 2023 (editorial). nejm.org
This page is for scientific information only. Sterling Research Group Ltd supplies retatrutide strictly for in vitro laboratory research. Not for human or animal use, and not for diagnostic or therapeutic purposes.