I love the niacin flush. when I first started I took 500mg once a day and had the flush. Over time I built up to where I am taking 3 doses of 1gram each per day. I usually have a flush each time, but it really depends on how empty my stomach is, how great of a need my body has for water, and if I had done any exercise. Combined with dry skin brushing the niacin flush is a wonderful thing to keep things moving. (not the bowells though....at least not for me) My skin tone seems more even since doing the flush. I have been doing it for almost a year. I do also take breaks and I have been dry skin brushing for about 3 years.