Gamma-Aminobutyric acid (GABA) is the most prevalent inhibitory neurotransmitters in the human central nervous system. GABA plays a wide variety of roles in many cognitive processes, however,
Pharmacology of GABA
GABA has many interesting properties in the nervous system. However, it is unable to cross the blood-brain-barrier when ingested orally. As a result, much GABA supplementation has no effects on the central nervous system. There may also be an effect of age on GABA uptake, as one study in rats demonstrated neonatal animals more readily uptake radio-labelled GABA.
There is some data to suggest that GABA supplementation may upregulate certain forms of growth hormone and that this release is dependent on dopamine signaling in the pituitary gland. However, that study only saw increases in certain forms of growth hormone (irGH and ifGH), that are not well understood. More work is needed to determine how different isoforms of growth hormone impact exercise efficiency and responses in humans.