Retatrutide dosing research guide

Retatrutide (LY3437943) is a long-acting acylated peptide that simultaneously agonises three receptors: glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and the glucagon receptor (GCGR). CAS: 2381879-91-8.

Developed as a next-generation metabolic peptide following the success of semaglutide (GLP-1 mono) and tirzepatide (GLP-1/GIP dual), the addition of glucagon agonism is hypothesised to increase energy expenditure beyond what dual agonism achieves alone.

Retatrutide is research-use only. It has not received regulatory approval for clinical or therapeutic use.

GLP-1 receptor (GLP-1R): Located in the pancreas, brain (hypothalamus), gut, heart and kidney. GLP-1R activation reduces appetite centrally, slows gastric emptying and stimulates glucose-dependent insulin secretion.

GIP receptor (GIPR): Expressed in adipose tissue, bone, brain and pancreatic beta cells. GIP has complex and context-dependent effects on fat metabolism and may enhance GLP-1R signalling.

Glucagon receptor (GCGR): Expressed predominantly in the liver and brown adipose tissue. Glucagon increases hepatic glucose output and stimulates lipolysis and thermogenesis. In the context of concurrent GLP-1R agonism (which counteracts hyperglycaemia), net glucagon agonism can increase energy expenditure without clinically significant hyperglycaemia in research models.

The Phase 2 clinical study (NCT04881760) by Eli Lilly tested escalating doses from 1 mg to 12 mg administered weekly subcutaneously in participants with obesity. After 24 weeks, the highest dose cohort achieved a mean weight reduction of approximately 17.5% from baseline.

For in vitro receptor binding assays, Retatrutide is typically prepared in DMSO at 10 mM stock concentration and diluted in assay buffer to the desired concentration.

For rodent pharmacokinetic studies, subcutaneous administration of 1–10 nmol/kg has been reported in published mouse models. These are research doses for animal models and are not applicable to human subjects.

Retatrutide is supplied as lyophilized powder. For research use:

• Reconstitute in bacteriostatic water (preferred for multi-dose vials) or sterile PBS
• Typical research stock concentration: 1 mg/mL
• Store reconstituted solution at 4 °C for up to 28 days; avoid freeze-thaw after reconstitution
• Protect from UV light

BioSyncLabs Retatrutide is independently verified to ≥ 99% purity by HPLC with NMR structural confirmation. The CoA is available for direct download on the Lab Results page and from each product listing.