GABA is a zwitterionic amino acid naturally present in fermented foods such as kimchi, kefir, miso, and tempeh. Commercial GABA for food use is produced by fermentation of L-glutamic acid or its monosodium salt (MSG) using glutamate decarboxylase (GAD)-producing Lactobacillus strains such as L. Brevis and L. Buchneri.
Clinical studies support its role in reducing anxiety. This improves sleep quality, and modestly lowering blood pressure through peripheral mechanisms. GABA is classified as a functional food ingredient in Japan (under the FOSHU system), China (GB/T standard), and Korea; it is commercially available as a dietary supplement ingredient in the US and EU with self-affirmed GRAS status in some applications. While not a traditional preservative, it is listed in some food additive frameworks and has antimicrobial properties at high concentrations.