The U.S. Pharmacopeia released analytical reference materials and guidance to help manufacturers ensure purity and detect product‑ and process‑related impurities for GLP‑1 peptides amid surging demand and reports of counterfeit products. USP framed the resources as tools for method development and validation to protect manufacturing quality and public safety. Concurrently, clinical and real‑world analyses show a substantial subset of patients are nonresponders to GLP‑1 receptor agonists for weight loss, prompting research into biological and mechanistic drivers of variable efficacy. Clinicians and researchers suggest heterogeneous pathophysiology of obesity underlies differential drug response. Together, the manufacturing standards and clinical findings highlight two parallel industry pressures: securing safe, high‑quality supply chains for peptide therapeutics and advancing mechanistic research to personalize GLP‑1 use.