My symptoms are very typical I think: terrible brain fog, severe tiredness, back ache, diarrhea , headache, sore throat, total loss of libido. Outside POIS episode, I never have even a single of these symtpoms.
They normally last 5 days, it is quite precise.
I tried quite a lot of the remedies advocated here, such as niacin, Inositol Hexanicotinate, fenugreek, anti-histamine, etc.
I have actually coupled my avoidance regime with diverse supplementations, and I cannot complain so far.