Jesper Mosolff Mathiesen is a Senior Principal Scientist at Zealand Pharma (Denmark), working on therapeutics for metabolic disease, and an Associate Professor in the Department of Drug Design and Pharmacology at the University of Copenhagen. His research addresses the structure, pharmacology and regulation of G protein-coupled receptors (GPCRs), with a long-standing focus on class C receptors such as the metabotropic glutamate and calcium-sensing receptors. He studies how small molecules, peptides and biologics differ in their effects on receptor activation and downstream cellular signaling. His current work pairs classical molecular pharmacology with biophysical and structural methods and computational modeling to understand allosteric modulation, functional selectivity and differential receptor regulation, and their relevance for the design of therapeutics.