As niacin is good remedy for nuber of poisers i must post this here:
Prostaglandin (PGD2) is the primary cause of the flushing reaction, with serotonin appearing to have a secondary role in this reaction.[23] The effect is mediated by prostaglandin E2 and D2 due to GPR109A activation of epidermal Langerhans cells and keratinocytes.[24][25] Langerhans cells use cyclooxygenase type 1 (COX-1) for PGE2 production and are more responsible for acute flushing, while keratinocytes are COX-2 dependent and are in active continued vasodilation.[26][27]
Flushing was often thought to involve histamine, but histamine has been shown not to be involved in the reaction.[23]
So here we can se conections with ours discusions here on forum,
i mean relate to prostagladins, cox1 ,cox2..