So what's the deal with GABA?  Why is it so special?

GABA: Gamma-Aminobutyric Acid
GABA is a non-protein amino acid that functions as a neurotransmitter (a chemical that facilitates communication between neurons). Neurotransmitters are either "excitatory" (i.e. they stimulate the firing of a neuron) or "inhibitory" (i.e., they tend to suppress neuron firing). GABA, which is produced from glutamate, is an inhibitory neurotransmitter. In fact, it's the primary inhibitory neurotransmitter in the brain.
Since GABA is a naturally-occurring, easily synthesized, physiologically-important compound, it's readily available in supplement form. It's also found in various functional food products. GABA tea is popular in Asia, for example, as is GABA-rich soy sauce and "GABA rice" (aka "germinated brown rice","sprouted brown rice"). The Jones Soda Company has even gotten in on the act, with Jones GABA- a functional tea-juice beverage. Why is GABA so popular? It appears to reduce anxiety and promote a sense of calm. Herbalists often recommend GABA as an alternative to the herb kava for people who want a natural tranquilizer. The effects of GABA are mild and it does not cause sedation. GABA is also used to promote sleep. This use is supported by a few small studies on animals and humans. Unfortunately, research in this area is limited, although there are a large number of positive-albeit anecdotal-reports. In addition to its use for improving relaxation/sleep, supplemental GABA may also enhance growth hormone (GH) release. This is why it is often included in various formulas designed to promote natural growth hormone secretion. Nonetheless, these products do not appear to produce results comparable to injections of genuine GH.