Levium - What it is: GABA is the primary inhibitory neurotransmitter in the brain. Many anxiolytics increase GABAergic tone (benzodiazepines, for example).Why it’s in Levium: Oral GABA supplements aim to increase GABAergic activity and promote relaxation. There’s mixed discussion in the literature about how much dietary GABA crosses the human blood-brain barrier; some studies and...