Question 1

What is Retatrutide (GLP-3 RT)?

Accepted Answer

Retatrutide (GLP-3 RT, LY3437943, CAS 2381089-83-2) is a synthetic 39-amino-acid investigational peptide classified as a triple GIP/GLP-1/glucagon receptor agonist (triagonist). It simultaneously binds and activates the GLP-1 receptor (GLP-1R), glucose-dependent insulinotropic polypeptide receptor (GIPR), and glucagon receptor (GCGR). MW 4731.33 g/mol. It is the first investigational triagonist to reach Phase 2 clinical evaluation. For in vitro laboratory research use only.

Question 2

How does GLP-3 RT differ from semaglutide and tirzepatide-class compounds?

Accepted Answer

Semaglutide activates only GLP-1R. Tirzepatide-class dual agonists (our GLP-2 TZ) activate GLP-1R and GIPR simultaneously. Retatrutide (GLP-3 RT) adds a third receptor - GCGR. Glucagon receptor activation is associated with increased hepatic glucose output and elevated energy expenditure in preclinical models, effects absent from both semaglutide and dual-agonist incretin compounds. That GCGR component is the pharmacological distinction that only a triple agonist can model.

Question 3

What does the glucagon receptor (GCGR) component add in research models?

Accepted Answer

In preclinical research models, GCGR activation is associated with increased hepatic glucose output, elevated energy expenditure, and enhanced fatty acid oxidation. These effects are not observed with GLP-1R or GIPR activation alone. The GCGR component is essential for modeling the complete triple-agonist pharmacological profile and for comparative studies examining what triple agonism adds beyond dual-agonist or single-agonist analogs.

Question 4

What is the CAS number and molecular weight of Retatrutide?

Accepted Answer

CAS number: 2381089-83-2. Molecular weight: 4731.33 g/mol. Investigational designation: LY3437943 (Eli Lilly). INN: Retatrutide. PubChem entry available. Also catalogued as GLP-3 RT and triple GIP/GLP-1/glucagon receptor agonist.

Question 5

What did the Phase 2 clinical trial on Retatrutide find?

Accepted Answer

A Phase 2 randomized controlled trial of Retatrutide (LY3437943) with body weight reduction as the primary endpoint at 48 weeks was published in the New England Journal of Medicine in 2023 (PMID 37351564). The trial examined multiple dose levels against placebo. As an investigational compound, Retatrutide has not received FDA approval. This data is referenced for research context only; we make no therapeutic claims.

Question 6

What is the difference between GLP-1, GIP, and glucagon receptor activation?

Accepted Answer

GLP-1R activation (as in semaglutide) stimulates insulin secretion and suppresses glucagon in a glucose-dependent manner. GIPR activation adds a second incretin pathway - glucose-dependent insulinotropic polypeptide signaling - contributing independently to insulin secretion and lipid metabolism. GCGR activation by glucagon drives hepatic glucose output and energy expenditure via cAMP-mediated glycogenolysis - the opposite metabolic direction from incretin signaling. Triple agonism targets all three simultaneously, creating pharmacological crosstalk that single and dual agonists cannot replicate.

Question 7

Is Retatrutide (GLP-3 RT) FDA approved?

Accepted Answer

No. Retatrutide (LY3437943) is an investigational compound in clinical development by Eli Lilly. It is not FDA approved for any indication. GLP-3 RT supplied here is for in vitro laboratory research use only. Not for human or animal use.

Question 8

What sizes are available for GLP-3 RT?

Accepted Answer

GLP-3 RT (Retatrutide) is available in 10mg, 20mg, 30mg, and 60mg vials - the widest size range in our GLP-1 class catalog. All sizes are ≥99% HPLC-purity lyophilized powder. This range supports everything from pilot receptor-binding assays (10mg) to full multi-dose dose-response experiments (60mg) without sourcing from multiple suppliers.

Question 9

What does the Certificate of Analysis (COA) for GLP-3 RT include?

Accepted Answer

The lot-specific COA for GLP-3 RT covers: HPLC purity (≥99% confirmed), LC-MS identity confirmation (full sequence verification), ICP-MS heavy metals panel, endotoxin testing (LAL method), and net content by weight. The COA is publicly available - access it using the lot number on your vial from our COA page. Most competitors provide HPLC data only; we include ICP-MS and endotoxin as standard.

Question 10

How should GLP-3 RT be stored and reconstituted?

Accepted Answer

Lyophilized GLP-3 RT should be stored at −20°C, protected from light and moisture. For long-term storage, −80°C is preferred. Reconstitute in sterile or bacteriostatic water at neutral pH. Aliquot into single-use portions immediately after reconstitution and store at −80°C. Reconstituted peptide is stable for up to 7 days at 4°C. Minimize freeze-thaw cycles - each cycle can reduce peptide integrity.

Question 11

How does GLP-3 RT compare to GLP-3R (the lipidated version) in research?

Accepted Answer

GLP-3 RT (Retatrutide) is the unlipidated triagonist - the same sequence as the Phase 2 clinical investigational compound. GLP-3R is a lipidated analog with a proprietary fatty acid conjugate (MW 4845.44 g/mol vs. 4731.33 g/mol for GLP-3 RT) that extends half-life and alters receptor-binding kinetics. Researchers frequently order both: GLP-3 RT as the clinical reference sequence, GLP-3R for pharmacokinetic half-life modeling, lipidation strategy research, and extended-duration assay protocols.

GLP-3 RT (Retatrutide) Research Peptide

Key Takeaways

Key Scientific Specifications

Research-Referenced Attributes

Also in This Research Area

Related Compounds

GLP-3 R

GLP-2 TZ