Complex carbohydrates increase glutamic acid/glutamate which forms glutamine and amino involved in producing GABA. Cooking destroys amino acids so eat as many raw foods as you can.
I would discuss this supplement with your Doctor as it has not been proven that GABA supplements cross the blood-brain barrier. Eating the right foods can boost you natural production of GABA.
This is just FYI and others may have information for you.
Kindly,
Kitt