Ostojic, Sergej M. (8552029600)Sergej M. (8552029600)OstojicOstojic, Jelena (12797904900)Jelena (12797904900)Ostojic2025-07-022025-07-022018https://doi.org/10.1007/s00394-017-1600-2https://www.scopus.com/inward/record.uri?eid=2-s2.0-85038370470&doi=10.1007%2fs00394-017-1600-2&partnerID=40&md5=1d3b9abb42e65cb23fc65dab6d2ab152https://remedy.med.bg.ac.rs/handle/123456789/12808We conducted a secondary analysis of a previously completed trial to determine the effects of 8-week guanidinoacetic acid (GAA) loading on brain GAA levels in five healthy men. Brain magnetic resonance spectroscopy (1H-MRS) was taken at baseline and post-administration, with spectra additionally analyzed for brain GAA and glutamate concentrations using TARQUIN 4.3.10 software. Brain GAA levels remained essentially unchanged at follow-up (an increase of 7.7% from baseline levels; 95% confidence interval, - 24.1% to 39.5%; P = 0.88) when averaged across 12 white and grey matter voxel locations. No significant changes were found for brain glutamate levels during the study (P = 0.64). Supplemental GAA appears to be safe intervention concerning brain GAA deposition, at least with GAA dosages used. © 2017, Springer-Verlag GmbH Germany, part of Springer Nature.GlutamateGuanidinoacetic acidMR spectroscopySupplementation