Dr. John Eiler is the Robert P. Sharp Professor of Geology and Geochemistry, as well as the Ted and Ginger Jenkins Leadership Chair of the Division of Geological and Planetary Sciences at Caltech. In this episode, John discusses his career, his research examining the molecular structure of isotopes, and how the approach that he and his collaborators have developed is relevant for the anti-doping community. He goes into detail on a recent PCC-funded research project investigating the use of molecular isotopic structure as a tool for doping forensics, their promising new results, and the impacts that this work could have to advance clean sport.