GABA (standalone supplement)

Tier 3 — weak evidence · Anxiety · Sleep · Relaxation

Standard GABA supplements probably do not cross the blood-brain barrier in meaningful amounts, which limits plausible central effects. Small RCTs (e.g. Abdou 2006) report modest increases in relaxation and alpha-wave activity, but later systematic reviews (Boonstra 2015) conclude human evidence is preliminary and inconsistent. The fermentation-derived PharmaGABA form has slightly more data than synthetic GABA. Generally safe, but overall evidence is weak.

Dose: 100–750 mg/day; PharmaGABA form may have better CNS effects