I know of three possible reasons: - your supplement is a dud - you took niacin too often (best to do it once a few days as body adapts quickly) - you have a

I know of three possible reasons: - your supplement is a dud - you took niacin too often (best to do it once a few days as body adapts quickly) - you have a gene mutation that prevents you from absorbing enough B3 (common in some schizophrenia cases that can be managed by huge doses of daily B3, like 4-10g)