Summary The neurotransmitter GABA and the redox compound glutathione can be measured in the human brain non- invasively using Hadamard-encoded edited MRS. Such measurements currently suffer from three major limitations: the confound of transverse relaxation (since edited MRS requires long echo times); incomplete spectral resolution between metabolites and the macromolecular background; and inadequate/inflexible modeling and quantification software. The overall goal of this R01 renewal period is to develop Hadamard- encoded edited MRS of GABA and Glutathione into a robust and reproducible tool for neuroscience. Building on the successful development of HERMES in the first funded period we will develop interleaved multi-spectrum acquisitions to improve robustness to changes in transverse relaxation and the macromolecule baseline and develop multi-spectrum linear combination methods within our software Osprey, including building a demographic model of the macromolecular background spectrum. This project will culminate in a patient-based validation study in subjects with Alzheimer’s Disease. The resulting data acquisition and analysis tools will be made available for dissemination to the clinical neuroscience and neuroimaging communities.