I think those doses build up in the body, and/of shift the homeostasis... I was taking 6mg of P5P and after 10 days I had a serotonin syndrome, taking P5P only depleted me from B2.
Long ago I read that B5 is a good anti-histamine, probably this is why it resolves brain fog.
I never tried piracetam. Daily consumption of fresh oregano (seasoning) resolved my brain fog.
good to know... I love oregano
I think that the B5 effect on Brain Fog is due to it's influence on acetylcholine.... Anything anti-histamine is good for me... I'm in a constant inflammatory, histamine fog