FAQ

GLP-1S is a synthetic glucagon-like peptide-1 (GLP-1) receptor agonist with the molecular formula C₁₈₇H₂₉₁N₄₅O₅₉ and a molecular weight of approximately 4,113.58 Da. CAS number: 910463-68-2. It shares 94% structural homology with native human GLP-1(7-37) but includes a C-18 fatty di-acid chain attached via a linker at position 26, which facilitates albumin binding and extends its half-life.

GLP-1S was first described by Novo Nordisk researchers and has been the subject of numerous clinical studies examining its pharmacokinetic and pharmacodynamic properties.

Lau J, et al. “Discovery of the Once-Weekly Glucagon-Like Peptide-1 (GLP-1) Analogue Semaglutide.” J Med Chem. 2015;58(18):7370-80. PubMed

GLP-1T is a 39-amino acid synthetic peptide that acts as a dual glucose-dependent insulinotropic polypeptide (GIP) and GLP-1 receptor agonist. Molecular formula: C₂₂₅H₃₄₈N₄₈O₆₈. Molecular weight: approximately 4,813.45 Da. CAS number: 2023788-19-2.

It is classified as an imbalanced dual agonist — exhibiting full efficacy at the GIP receptor but biased, partial agonism at the GLP-1 receptor, favoring cAMP signaling over β-arrestin recruitment.

Willard FS, et al. “Tirzepatide is an imbalanced and biased dual GIP and GLP-1 receptor agonist.” JCI Insight. 2020;5(17):e140532. PMC

GLP-3R (LY3437943) is a synthetic peptide that functions as a triple agonist at three receptors: GLP-1, GIP, and glucagon (GCGR). CAS number: 2381089-83-2. Molecular weight: approximately 4,632.28 Da. It adopts a single continuous alpha-helical structure that enables simultaneous engagement with all three receptor types.

The glucagon receptor component is hypothesized to contribute additional metabolic effects through hepatic pathways, including increased energy expenditure and lipid oxidation.

Coskun T, et al. “LY3437943, a novel triple GIP, GLP-1, and glucagon receptor agonist.” Cell Metab. 2022;34(9):1234-1247. PubMed

GLP-1C is a long-acting synthetic analog of amylin (islet amyloid polypeptide), not a GLP-1 receptor agonist. CAS number: 2196055-94-8. It binds to amylin receptors (AMY1R, AMY2R, AMY3R) and the calcitonin receptor (CTR).

N-terminal lipidation enables extended albumin binding, giving it a significantly longer half-life compared to native amylin. It is structurally and mechanistically distinct from GLP-1 receptor agonists, though the two compound classes have been studied in combination.

Cao J, et al. “Structural and dynamic features of Cagrilintide binding to calcitonin and amylin receptors.” Nat Commun. 2025;16:58680. Nature

High-Performance Liquid Chromatography (HPLC) is the standard analytical method for determining peptide purity. A sample is dissolved in a mobile phase and passed through a chromatographic column. A UV detector (typically at 220nm) measures the elution profile.

Purity is calculated as the target peptide peak area relative to total peak area. Panda Peptides requires ≥99% HPLC purity on all products. Each batch is tested by Janoshik Analytical, an independent third-party laboratory.

A Certificate of Analysis is a document issued by a testing laboratory reporting results of analytical testing on a specific batch. For peptides, COAs typically include HPLC purity analysis, mass spectrometry confirmation (MS), and appearance data.

Third-party COAs — from labs independent of the manufacturer — provide greater credibility. Panda Peptides publishes COAs from Janoshik Analytical for every batch. All reports are on our Lab Reports page with verification links.

GLP-1 and GIP are both incretin hormones involved in glucose metabolism, but they act through distinct receptors and signaling pathways.

GLP-1 receptor agonists (e.g., GLP-1S) primarily activate GLP-1R, expressed in the pancreas, brain, and GI tract. GIP receptor agonists target GIPR, with different tissue distribution including adipose and bone. Dual agonists like GLP-1T engage both; triple agonists like GLP-3R add glucagon receptor activity.

Campbell JE, Drucker DJ. “Pharmacology, physiology, and mechanisms of incretin hormone action.” Cell Metab. 2013;17(6):819-837. PubMed

Mass spectrometry (MS) ionizes peptide molecules and measures their mass-to-charge ratio. The observed molecular mass is compared against the theoretical weight. Common methods include MALDI-TOF and ESI-MS.

A match within ±1 Da confirms identity. This complements HPLC, which measures purity but does not confirm structural identity.

Research Use Only (RUO) indicates a product is intended solely for laboratory research, analytical testing, and scientific investigation. RUO products have not been approved by the FDA for diagnostic, therapeutic, or clinical use.

Under the FDA’s framework, RUO products are exempt from certain regulatory requirements. Purchasers are responsible for ensuring compliance with all applicable regulations. All Panda Peptides products are sold exclusively for research use.