In GABA-edited spectroscopy signal of macromolecules overlaps the signal of GABA. This macromolecular contribution to GABA signal (GABA+) is variable throughout the brain and can bias the quantification. We aimed to map the signal of macromolecules at 2.99 ppm using metabolite-nulled 3D MEGA-LASER MRSI. We found the GABA+/total creatine to be higher in white matter (45%), which contradicts the literature. The MM2.99ppm was found higher in white matter as well (24%). The macromolecular tissue distribution is among other factors affecting the GABA+ signal, therefore the detection of GABA is preferable to GABA+ if the removal of macromolecules is possible.