I've written about various candida metabolites in my book Candida Crusher that often underpin brain fog, metabolites like mannan and gliotoxin. Mannan is a type of polysaccaharide which are cell wall fragments of candida, they kind of become liberated like "shrapnel" after a grenade explodes (candida dies), and can travel anywhere the circulation will take them, including the brain. The half-life of mannan can be many months, there are many studies which have verified this. Gliotoxin is a kind of toxin created by yeasts that can effect your immune function and reduce its effectiveness in eradicating candida, it is a kind of "self-preservation" mechanism by yeasts to prolong their survival. A good way to work on eradicating metabolites is to get your immune system as powered up as much you can, and boosting adrenal function is certainly a great start. This will improve the gut immune integrity to a high degree as well and can help fix up a leaky gut which commonly occurs in those with brain fog.