Glutamine in combination with Vitamin B6 are precursors for the bio-synthesis of the neurotransmitter – GABA (gamma-amino butyric acid). The role of GABA in the brain and body is to calm you down. Low levels of GABA might cause panic attacks, feelings of exhaustion, feeling overworked, and overwhelmed. A lack of GABA is also associated with a class of neurological disorders characterized by convulsive and non-convulsive seizures, as in epilepsy.
In addition to its role in supporting the brains ability to mount a healthy stress response, glutamine has benefits for the body as well. It is typically used in sports nutrition for maintenance and repair of sore muscles. And in the role of the digestive system, glutamine is also an oxidizing energy source for the cells of the upper GI tract. By promoting a healthy gut results in an overall improved immune system benefit.
Though the body produces glutamine, it may not be enough during conditions of both physical stress (working out) and mental or emotional stress (the burden of life stressors). Under these conditions the body and brain may require more glutamine than it can produce. When both body and brain are functioning from an optimal state with balanced nutrients such as glutamine, we are more efficient, more relaxed and calmer.
Myer Jerrold S., Quenzer Linda F , Psychoparmacology , Drugs, the Brain, and Behavior. 2nd Ed Chapter 8 .2013