Retatrutide (LY3437943) is studied as the first single-molecule triple GIP/GLP-1/glucagon receptor agonist. In-vitro mechanism, receptor pharmacology and handling for NZ laboratories.
Retatrutide (development code LY3437943) is a synthetic 39-residue peptide studied in vitro as a triple agonist engaging the glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1) and glucagon (GCG) receptors. It is one of the most actively studied multi-receptor incretin analogs in current cell-based pharmacology literature. This profile is a strictly in-vitro research reference.
What is retatrutide?
Retatrutide is a peptide analog engineered from the GIP backbone with amino-acid substitutions and a fatty-acid diacid linker attached to a lysine residue. In stability assays, the linker is studied for its role in reversible albumin association. Unlike tirzepatide (dual GIP/GLP-1) or semaglutide (GLP-1 only), retatrutide adds glucagon-receptor agonism to the panel of receptors researchers can characterise with a single ligand.
Retatrutide identity and specifications
| Attribute | Value |
|---|---|
| Development code | LY3437943 |
| Class | Triple GIP/GLP-1/glucagon receptor agonist (research reference) |
| Length | 39 amino acid residues |
| Molecular formula | C221H343N51O61 |
| Average mass | ~4731 Da |
| Backbone origin | GIP-derived, triple cross-reactive |
| Format supplied | Lyophilised powder, research use only |
| Storage (lyophilised) | -20 °C, protected from moisture |
Triple receptor pharmacology in vitro
Retatrutide's defining research interest is balanced potency across three receptor systems in cell-based assays — a combination not seen in single-receptor incretin ligands.
- GIP receptor agonism — studied via cAMP reporter assays in GIP-R-transfected cell lines.
- GLP-1 receptor agonism — studied via cAMP accumulation in GLP-1R-transfected cell lines.
- Glucagon receptor agonism — studied in hepatocyte and GCG-R reporter models for signalling characterisation.
- Fatty-acid diacid linker is studied for its contribution to serum albumin association and apparent in-vitro stability.
Published in-vitro and structural literature
| Research focus | Assay type | Typical readout studied |
|---|---|---|
| Tri-receptor binding profile | Parallel cAMP reporter panel | EC50 per receptor |
| Selectivity vs dual agonists | Comparative receptor screening | Fold-selectivity |
| Plasma protein stability | Serum incubation + LC-MS | Apparent degradation half-life |
Handling and storage reference
- Supplied as lyophilised powder for laboratory reconstitution into assay buffer only.
- Lyophilised powder: stable at -20 °C for 24+ months when protected from moisture.
- Reconstituted working solutions: store at 2–8 °C and use within your own validated assay window.
- Avoid repeated freeze–thaw cycles, which compromise assay reproducibility.
Retatrutide vs tirzepatide vs semaglutide: receptor coverage
| Attribute | Retatrutide | Tirzepatide | Semaglutide |
|---|---|---|---|
| Receptors studied | GIP + GLP-1 + GCG | GIP + GLP-1 | GLP-1 only |
| Backbone | GIP-derived, triple cross-reactive | GIP-derived, dual cross-reactive | GLP-1(7-37) analog |
| Research stage in literature | Actively characterised, multi-receptor | Well-characterised, dual-receptor | Extensively characterised, single-receptor |
Certificate of analysis expectations
- Batch identifier and synthesis date traceable to the lot record
- HPLC purity ≥98% (typically ≥99% for peptides under 30 residues)
- LC-MS confirmed monoisotopic or average mass within ±0.5 Da of theoretical
- Counterion identity and content (acetate or trifluoroacetate) reported
- Bacterial endotoxin and residual solvents per the analytical method
Sourcing research retatrutide in New Zealand
Kiwi Peps supplies retatrutide verified to the KP-99 Purity Standard (99%+ HPLC-MS), with every batch recorded in The Batch Book. Orders cleared by 2pm NZT dispatch the same working day under Bench-Ready Dispatch, tracked nationwide with NZ Post CourierPost. Strictly for in-vitro research use — not for human or veterinary administration.
Frequently asked questions
What is retatrutide used for in research?
Retatrutide is used as the reference triple GIP/GLP-1/glucagon agonist for in-vitro receptor pharmacology, cell-based signalling studies and comparative incretin-receptor screening.
What makes retatrutide different from tirzepatide at the receptor level?
Retatrutide adds glucagon-receptor agonism to tirzepatide's dual GIP/GLP-1 profile, giving researchers a third receptor system to characterise with the same ligand.
What is the molecular weight of retatrutide?
Retatrutide has an average molecular mass of approximately 4731 Da across its 39-residue sequence.
How is retatrutide supplied by Kiwi Peps?
As lyophilised powder verified to the KP-99 Purity Standard, with a HPLC-MS certificate of analysis available through The Batch Book.
Does retatrutide need cold storage?
Lyophilised retatrutide should be stored at -20 °C, protected from moisture, prior to reconstitution into assay buffer.
Is retatrutide approved for any human therapeutic use in New Zealand?
No. Kiwi Peps supplies retatrutide strictly as a research-use-only peptide for in-vitro laboratory work.
