I went down the rabbit hole on GABA — the brain's main 'calm down' signal — and learned certain gut bacteria like Bacteroides actually produce it. Whether gut GABA reaches the brain is genuinely unsettled, so I treated this as an experiment, not a cure. For eight weeks I ate a small portion of a fermented food every day and kept my fiber up so those bugs had something to work with. I logged 'calm' and sleep. My sleep score moved first, then my daytime baseline felt a notch less jittery. Small effect, but real enough that I've kept it up. The honest version: I can't tell you it was the GABA. I can tell you my own numbers got better.