That has happened to me before. Something I try that causes the flush to occur much faster is open up the capsules and pour them in a blender (it doesn't mix well by hand for some reason) with 1 cup water, and blend for about 20 seconds until the niacin is dissolved into the water. Then drink the liquid. The flush occurs much faster this way because it's already dissolved. The only negative thing about this is the taste. I can't stand the taste, but it's really not too bad after you drink it, especially if you drink a cup of pure water after.