A randomized, single blind, placebo-controlled, crossover study from 2006, investigated impacts of GABA supplementation in 63 healthy subjects with three primary endpoints: brain wave patterns (using EEG), assessment of mental state (using Profile of Mood Scale and Visual Analogue Scale) during and following stressful events. The EEG measurements at 0, 30 and 60 min showed less pronounced decrease in alpha waves 30 minutes post-administration in the GABA treated group compared with placebo group.
References:
Yoto, A., Murao, S., Motoki, M., Yokoyama, Y., Horie, N., Takeshima, K., Masuda, K., Kim, M., & Yokogoshi, H. (2012). Oral intake of γ-aminobutyric acid affects mood and activities of central nervous system during stressed condition induced by mental tasks. Amino acids, 43(3), 1331–1337. https://doi.org/10.1007/s00726-011-1206-6