X-nuclei imaging like sodium MRI offers complementary information to 1H-based imaging. However, its clinical translation is hampered by the significant increase in scan time required for the acquisition of an additional nuclei. Addressing this challenge, this work introduces Multiplexed Measurement of Multiple Nuclei (M3N) sequences and proposes MERINA-MP2RAGE, a multi-nuclei sequence, that embeds sodium MRI in a 1H-MP2RAGE acquisition. The developed sequence was implemented on a 7T MRI and tested in phantom and human in vivo experiments. Merging 1H-MP2RAGE and 23Na-MERINA reduces the total scan time by 40% compared to sequential acquisitions while maintaining uncompromised image quality.