Gaba itself doesn't work, as it's not missive to the blood/brain barrier. There are formulations meant to address this problem one called Phenibut, another Picamilon. Picamilon is supposedly much better--I haven't tried it, personally. Both are sold as supplements, and can be purchased online. Phenibut can occasionally be found in specialty stores, but not Picamilon, as far as I know. Purchasing GABA, itself, is a waste of money. There are other formulations/supplemets better for sleep. 5-HTP is one...but should be avoided if one is taking any SSRI (possible serotonin syndrome)...it's especially effective in those who crave carbs later in the evening. L-Theanine is another, as well as Melatonin (6mg, at least)...though Melatonin is not particularly effective for those under age 50, or so often not until age 60). They've long been trying to come up with a pharm. that replicates GABA purely in its action--that's what gabapentin was meant to do...but doesn't. They haven't had much luck so far...although many recommend Baclofen, as it has GABAergic properties (though it's a prescription). I'm not a licensed healthcare practitioner, and any supplements should be used with the knowledge of a physician, especially when combined with other medications.
Magnesium is effective for many as a muscle relaxant...supposedly over 90% of U.S. citizens are magnesium deficient, and it's necessary for nerve conduction. Calcium, also, but recent studies suggest that previously recommended levels of Calcium are in fact too high, and may have adverse effects, long term, at previously recommended dosages.
Good luck.
