i am suffering with brain fog too and my brain fog also gets much better in the evening about 8ish.
My fog seems to correlate with a weird UTI infection I have had. I have been on and off Antibiotics for 3 months as they improve the fog. But the Antibiotics havent caused it because I got it before I started them.
I think that something is building up in the body/ blood/ brain overnight and the reason it gets better at night is because some of it is weed out during the day. Thats what it feels like to me.
I am drinking lots of water.
I am thinking of trying h2o2 ingestion to try to get rid of whatever is causing the build up (whatever the build up is) but I am worried. I have read that ingesting it can cause stomach cancer.
I just want this brain fog gone so i can continue with my life.