The U.S. Pharmacopeia released reference standards and analytical reference materials to help manufacturers test GLP‑1 peptide therapeutics for product‑ and process‑related impurities amid surging demand and reports of counterfeit injections. USP’s materials aim to support method development and validation across rapidly scaling peptide production networks. Separately, clinical observations and real‑world data continue to show a substantial fraction of patients—up to one‑in‑four in some datasets—do not achieve meaningful weight loss on GLP‑1 receptor agonists. Researchers and clinicians are investigating biological and pathway‑level differences that may underlie nonresponse to agents such as semaglutide. The twin issues—scaling quality control for complex peptides and heterogeneous patient responses—heighten scrutiny on manufacturing controls, supply‑chain integrity and personalized approaches to obesity pharmacotherapy.