I was prescribed this supplement by my integrative Medicine doc. in a variation called Kavinace. It has calmed night time anxiety and is helping me sleep better.
Here's an excerpt from WebMD:
GABA is a chemical that is made in the brain.
GABA is taken by mouth for relieving anxiety, improving mood, reducing symptoms of premenstrual syndrome (PMS), and treating attention deficit-hyperactivity disorder (ADHD). It is also used for promoting lean muscle growth, burning fat, stabilizing blood pressure, and relieving pain.
GABA is used under the tongue for increasing the sense of well-being, relieving injuries, improving exercise tolerance, decreasing body fat, and increasing lean body weight.