V (Seattle, Wa) on 02/11/2011:

I had not taken niacin for a long time. I also have a cold. One of those icky sinus congesting colds. My mouth is dry and my snot is thick and sticky and yellow (sorry for the imagery). I just took a high dose of niacin (1000mg) and when it kicked in and my body began to flush I had the urge to blow my nose and when I did my sinuses cleared out completely and they have not been this clear in over a week). I'm not 100% sure if niacin is related to my sinuses clearing but the odds of them clearing out for the first time in a week within 20 minutes of taking niacin would be low. After my niacin flush began to disapear my sinuses began to congest again. This could be a coinsidence but I don't think so.

If you have not taken niacin before you should know that it will make your capiliaries open and when they do blood flows much more easily. Because your capiliaries have expanded they are larger and more blood flows through and you can see this happen as your body turns pink/red. You can also feel the increase in blood flow with a tingling/itchy feeling as well as a warm/hot sensation which are due to vastly improved circulation. These sensations will not appear imediately, they will build up over a ten to twenty minute time period. Because the heat and itching will gradually increase do not be alarmed, after 10-20 minutes the effect will plateu and then decrease and the effect will be over, no matter how unpleasant it was.

I do not recomend taking niacin for the first time at least 2-3 hours before an event or meeting friends because the reddening of your skin may embarass you if you are not used to it (even if you are used to it, I can tell you it is not a flattering look, lol). Also while niacin itself (as far as I know) does not interfere with sleep the itching feeling can make it difficult to fall asleep if not impossible or may wake you if you fall asleep before it kicks in, so I do not reccomend taking it before bed until you know if you can sleep with it.