> the flush can open up veins and flood hard to reach extremities of the body

What does it mean if I don’t flush? Is the supplement a dud?

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)