NA-931 (Quadruple Agonist) Peptide

NA-931 is a first-in-class, orally active quadruple receptor agonist developed by an investigational sponsor, Inc. It simultaneously activates four metabolic receptors: GLP-1R, GIPR, GCGR (glucagon), and IGF-1R — making it the only known compound to engage all four pathways in a single molecule.

Unlike injectable peptide agonists (GLP-1 agonist peptide, GLP dual agonist peptide, GLP triple agonist peptide), NA-931 is derived from a cyclic glycine-proline (cGP) fragment of insulin-like growth factor-1 (IGF-1), giving it oral bioavailability. This represents a paradigm shift from injectable peptides to orally administered metabolic therapeutics.

The compound was presented at EASD 2025 and ADA 2025 conferences with Phase 2 data showing -9.2% body metabolic regulation research at 12 weeks via oral dosing — a rate comparable to injectable GLP-1 agonist peptide despite the convenience of oral administration.

NA-931 is unique in metabolic pharmacology as it activates four receptors through a single molecular entity:

• GLP-1 Receptor: Appetite suppression via hypothalamic POMC/CART neurons, glucose-dependent insulin secretion, gastric emptying delay — same pathway as GLP-1 agonist peptide
• GIP Receptor: Enhanced incretin effect, amplified insulin response, adipose tissue lipid metabolism — same addition as GLP dual agonist peptide
• Glucagon Receptor: Increased hepatic energy expenditure, fat oxidation, thermogenesis — same addition as GLP triple agonist peptide
• IGF-1 Receptor: The novel fourth target. IGF-1R activation promotes lean body mass preservation, metabolic rate maintenance, and potentially counteracts the muscle loss typically seen with aggressive metabolic regulation research. This is the key differentiator from all existing triple agonists.

Oral bioavailability: The cyclic glycine-proline structure enables gastrointestinal absorption without the need for permeation enhancers (like SNAC used in oral GLP-1 agonist peptide). This simplifies formulation and may improve tolerability.

Notes on classification. NA-931 is mechanistically grouped with the emerging class of multi-incretin agonists (alongside tirzepatide [GLP-1/GIP] and retatrutide [GLP-1/GIP/GCG]) but is structurally distinct in two important ways. First, it is a small molecule rather than a 39–49 amino-acid lipidated peptide, which underlies its oral bioavailability without absorption enhancers such as SNAC. Second, the addition of IGF-1R engagement provides a putative anabolic signaling arm that is absent from all currently marketed or late-stage incretin-based therapeutics. This combination places NA-931 in a novel pharmacological category that does not have a direct comparator in the approved drug landscape.

Structural context. The cyclic glycine-proline scaffold was originally characterized as an endogenous regulator of IGF-1 bioavailability through modulation of IGF-binding protein-3 (IGFBP-3) interactions. Synthetic cGP analogs have been investigated for neuroprotective and metabolic indications and are known to cross the blood-brain barrier — a property that may also contribute to central appetite regulation in conjunction with GLP-1R signaling. The proprietary nature of the NA-931 structure means that full SAR, crystallographic, and binding-affinity data remain unpublished pending sponsor disclosure.

NA-931 is supplied as a lyophilized white powder intended for laboratory research use only. Although the parent clinical formulation is being developed for oral administration, the research-grade material requires standard peptide reconstitution practices for in vitro and ex vivo investigation. Researchers should follow rigorous aseptic technique when reconstituting and aliquoting this quadruple agonist to preserve receptor-binding activity across the GLP-1, GIP, glucagon, and IGF-1 receptor sites.

Recommended Reconstitution Protocol

1. Equilibrate the vial to room temperature for 20-30 minutes before opening to prevent moisture condensation on the lyophilized cake.
2. Select an appropriate diluent. Bacteriostatic water (0.9% benzyl alcohol) is suitable for short-term in vitro work. For sensitive receptor binding assays, sterile water for injection or phosphate-buffered saline (pH 7.4) is preferred.
3. Calculate target concentration. For a typical 5 mg vial, adding 1 mL of diluent yields a 5 mg/mL stock solution. For a 10 mg vial, 2 mL produces the same concentration.
4. Inject the diluent slowly down the inner wall of the vial — never directly onto the peptide cake. This prevents mechanical disruption of the cyclic structure.
5. Gently swirl the vial in a circular motion until the powder fully dissolves. Do not shake, vortex, or invert vigorously, as agitation can denature the cyclic IGF-1-derived backbone and disrupt receptor-binding conformation.
6. Inspect visually. The reconstituted solution should appear clear and colorless. Any cloudiness, particulates, or discoloration indicates degradation and the sample should be discarded.
7. Aliquot immediately into low-binding polypropylene tubes to minimize peptide adsorption to vessel walls. Single-use aliquots prevent repeated freeze-thaw cycles.

Compound-Specific Handling Notes

NA-931 contains a cyclic peptide architecture derived from an IGF-1 metabolite fragment. The cyclization is critical for maintaining quadruple receptor selectivity, and the molecule is particularly sensitive to:

• Oxidation: Avoid prolonged exposure to air; flush vials with inert gas (nitrogen or argon) when possible during aliquoting.
• pH extremes: Maintain solutions between pH 6.5-7.5. Acidic or basic conditions can hydrolyze amide bonds within the cyclic core.
• Light exposure: Store reconstituted material in amber tubes or wrap clear tubes in foil to prevent photodegradation of aromatic residues.
• Surface adsorption: At low working concentrations (<1 µg/mL), add 0.01-0.1% bovine serum albumin (BSA) as a carrier protein to prevent peptide loss to plastic surfaces.

For receptor binding studies that require comparison with semaglutide, tirzepatide, or retatrutide, prepare all peptides using identical reconstitution buffers and concentration ranges to ensure valid head-to-head comparison of EC50 values across GLP-1R, GIP-R, GCG-R, and IGF-1R assay systems.

Formulation context. NA-931 is an orally bioavailable small molecule (cyclic glycine-proline analog derived from the IGF-1 N-terminal tripeptide), not a lyophilized peptide. This fundamentally changes the storage and handling profile compared with injectable incretin analogs such as semaglutide or tirzepatide, which require cold-chain logistics and aseptic reconstitution. Investigational tablet or capsule formulations of NA-931 are designed for ambient storage and dispensed in moisture-barrier blister packs or HDPE bottles with desiccant.

Recommended laboratory storage.

• Temperature: Controlled room temperature, 15–25 °C (59–77 °F). Brief excursions to 30 °C are typically tolerated for orally dosed small molecules, but prolonged exposure above 30 °C should be avoided pending stability data from the sponsor.
• Humidity: Protect from moisture. Relative humidity below 60% is preferred; cGP analogs can be hygroscopic, and water uptake may accelerate hydrolytic degradation of the diketopiperazine ring.
• Light: Store in original opaque or amber packaging. While the cGP scaffold is not strongly chromophoric, prolonged UV exposure can promote oxidative side reactions.
• Container integrity: Keep tablets/capsules in original blister or sealed bottle until use to maintain desiccant function.

Long-term and working storage. For extended laboratory archival (>12 months), refrigerated storage at 2–8 °C in a desiccated, light-protected container can extend shelf life, but the material should be equilibrated to room temperature in its sealed container before opening to prevent condensation on the dosage form. Repeated temperature cycling should be minimized.

Stability advantages over injectable peptides. Compared with GLP-1/GIP peptide analogs, cyclic dipeptide-derived small molecules such as NA-931 generally exhibit:

• Greater resistance to enzymatic degradation (no DPP-4 or neprilysin susceptibility).
• Lower sensitivity to aggregation and fibrillation, which is a major stability concern for amphipathic peptides such as liraglutide and tirzepatide.
• Tolerance to ambient handling, eliminating the need for −20 °C lyophilizate storage or 2–8 °C reconstituted-solution storage.
• Compatibility with standard solid-dose stability protocols (ICH Q1A(R2)) rather than the more stringent biologics stability framework.

Handling in the research setting. Use clean, dry forceps or gloved hands to dispense individual units; avoid crushing or splitting tablets unless dissolution studies require it, as this can expose the active to moisture and oxygen. For ex vivo or in vitro pharmacology work, stock solutions are typically prepared in DMSO at 10–50 mM and stored in single-use aliquots at −20 °C or −80 °C to avoid freeze–thaw cycles. Aqueous working dilutions should be prepared fresh on the day of the experiment, as cyclic dipeptide analogs can undergo slow ring-opening hydrolysis at neutral to alkaline pH.

Documentation. Maintain a chain-of-custody log including lot number, receipt date, storage temperature excursions, and opening date. Investigational compounds without published stability dossiers should be re-qualified by analytical assay (HPLC-UV or LC-MS) if used beyond the sponsor-stated retest period. NA-931 is for laboratory research use only; it is not approved for human or veterinary administration, and these storage notes are intended solely to preserve analytical integrity of the research material.