What is PEP-RTA-3, and what is it studied for?

What is the structure of PEP-RTA-3?

The sequence is built on the glucagon backbone with substitutions that add GIP and GLP-1 receptor activity, and it carries a C20 fatty-diacid side chain that binds albumin and extends the circulating half-life to days. It is supplied as a lyophilized acetate salt. The calculated mass is confirmed by LC-MS on every lot and the HPLC purity is reported at 214 nm.

Identifier	Value
Molecular formula	C221H342N46O68
Molecular weight	4731 g/mol
Residues	39
CAS number	not recorded
PubChem CID	171390338
Current lot	RETA10-0803

How is PEP-RTA-3 thought to work?

GLP-1 receptor activation increases glucose-dependent insulin secretion and slows gastric emptying; GIP receptor activation is thought to potentiate insulin release and modulate adipose tissue; glucagon receptor activation raises energy expenditure and hepatic fat oxidation. The interest in PEP-RTA-3 is the balance between them: the glucagon component would raise glucose on its own, and the incretin components are what allow it to be tolerated in the models where it has been tested.

Which research areas use PEP-RTA-3?

Area	Typical models and endpoints
Receptor pharmacology	Potency and selectivity at the three receptors in cAMP assays, and how the ratio of activity compares with PEP-TZP-2 and PEP-SMG-1.
Energy expenditure	Indirect calorimetry in rodent models to separate reduced intake from increased expenditure, the signature of the glucagon component.
Adipose and liver	Body composition, hepatic lipid content and adipose remodelling in diet-induced obesity models.
Comparative studies	Head-to-head arms against single and dual agonists at matched exposure.

What does the published literature show?

The phase 2 clinical programme reported in the New England Journal of Medicine in 2023 (Jastreboff and colleagues) described dose-dependent weight reduction over 48 weeks that exceeded what had been seen with dual agonists, along with the gastrointestinal effects familiar from the incretin class. Preclinical work in rodents established the energy-expenditure contribution of the glucagon arm. That programme is why this is the most-requested comparator compound in the metabolic category; they are clinical findings in a regulated trial setting and do not describe research use of the material sold here.

How is PEP-RTA-3 handled in the laboratory?

PEP-RTA-3 is slower to dissolve than short peptides because of the fatty-diacid side chain. Add bacteriostatic water down the vial wall and allow several minutes with gentle swirling. The solution is light-sensitive: keep the vial in its carton at 2 to 8°C and use within the 28-day certificate window. The concentration table covers dilution volumes and microlitre aliquots; the storage guide covers stability by compound class.

What does the current certificate show?

Lot RETA10-0803 tested at 99.83% purity by RP-HPLC (214 nm), identity confirmed by LC-MS/MS, endotoxin <0.05 EU/mL. The certificate is in the COA library and the lot number on the vial matches it. Sold as 10 mg per vial at $105, for laboratory research only.

Certificate history for PEP-RTA-3

Every certificate the library holds for this compound, newest first. A replaced lot stays listed so the history can be read; the certificate dataset reads all 114 together.

Frequently asked questions

References

1. Jastreboff AM et al. N Engl J Med. 2023.
2. Coskun T et al. Cell Metab. 2022.

Clinical results cited above describe regulated trials of pharmaceutical products and are given as context for research interest only. Nothing on this page describes or recommends use of the material sold here in humans or animals.