GABA is an all natural protein based neurotransmitter that has the following action:
Naturally Releases Human Growth Hormones
Helps Increase Lean Muscle Mass
Improves Sleep Cycles
Assists in Stabilizing Blood Pressure
May Assist in Relieving Pain
GABA is important in helping the body to naturally regulate nerve function and inhibit excitation in the brain. GABA is helpful in bringing calmness to the body, promoting tranquility and peace in times of stress and anxiety. It is also a known precursor to another important neurotransmitter, gamma-hydroxybutyrate (GHB), which is a natural sleep inducing compound in the brain, encouraging the body to produce its own native tryptophan, which in turn is the natural precursor to the sleep neurotransmitter, serotonin. For adults, take 2 at night and one in the morning. Dosage for children depends upon body weight.
Gamma-Aminobutyric Acid can be used much like tranquilizers, but without the possibility of addiction. Taurine is the precursor to GABA and may be used in addition to build up the supply of GABA in the central nervous system as GABA, when taken orally, does not cross the blood brain barrier however it still has calming effects in the body.
It is sometimes used to increase sex drive as well as with prostate problems, since it also assists with the release of sex hormones.
So, reading this, although gaba doesn't cross BBB it still calms the body and acts like a tranquilizer.
My conclusion to this is, just taking a couple to calm down quickly is probably not the way to use this, it seems to build up and have a accumulative affect on the nervous system