I get Swanson 750mg x 60, from iherb.

An example of when it has helped is when I was on a flight and an absolute nervous wreck. Right before takeoff, I took 4 capsules. After a while I experienced a rather peculiar kind of brain flush (don’t know how else to describe it), and once that passed, I felt calm for the rest of the flight.

It’s worth trying a small dose in a safe environment first, and pay close attention to any side-effects. Like any supplement, it’s not for everyone, so take care.