slowly up the dosage
always start at the lowest possible dose. I usally start at something like half a pill, i.e. 50mg. If you get a reaction, i.e. red and itchy, continue taking that dose until you get no more reaction. Then up the dose, and repeat. You can definitely take it up 3 or 4000mg. I know people who do a lot more than that. The key is to up the gradient. Dont take too much at once. Let your body get used to it, and dont up the dose while you are still getting a reaction!
Did you people know that niacin detoxes your body, including the UV from sunburns, radioactive material, pollution in the air etc? Proven fact. Every time I take niacin after summer I see where I got sunburnt, but only for a few days, then its gone.
And whatever you do, do NOT take niacin on an empty stomach! It will hurt like goddamn hell and you will feel like throwing up your intestines.