I think what I just experienced was a niacin flush, but it was the worst I have ever had. I took a B-right, it has 25mg of niacin. About 45 min. to an hour later I got a bad pain in my stomach then it moved up to my chest. Next thing my skin started to burn and itch and I looked like I had a blotchy sunburn. I've had this before but never with stomach pain. Also my face swelled a little. Could this small amount of niacin cause this effect?

I tried a plain niacin many years ago, I forgot what amount it was, but I had the flushing and red skin, no stomach pain though..
It didn't last very long for me 15-30 minutes maybe..and faded away.

If the B3 is Niacin and not niacinamide form, yes that is enough to flush for some people. On an empty stomach it would be faster.

Niacinamide however, does not produce the flush and is in this form in most B-complex mixtures.

You can block the flush with an aspirin taken 1/2 hour before.
Also if you use ACE inhibitors, these release brandykinin also and would be additive with pure niacin. So smaller doses might produce a flush when they would not, if no ACE inhibitor was present.

25mg isn't much, it might cause that.. but your body adjusts. I've taken 1gram with flush that was about the same scale as when I started taking 100mg at first.

Recent studies show that raising HDL may not really do anything, so talk to your dr about the use of Niacin for cholesterol management.

(note: still good for energy), but you don't need huge dosages for that.

I find that I need to take the my B complex with in the middle of a meal. And I usually take 500 mg vit c about an hour before to head off the flush.

I do not think that what you experienced was a niacin flush.
25 mg is really low, especially if you compare it to the official
daily recommended dose of 20 mg. However, I might be mistaken here.

The best tip for preventing side effects is taking in the aspirin
30 minutes prior to the overdose. However, vitamin c tablets
and garlic extract can work very well too. In any case,
be sure to drink a lot of water and avoid alcohol.

**

That sounds exactly like what I experience when I take niacin, though I didn't always. When I first started taking it several years ago, I had no flushing, and so when it finally appeared, with the stomach pain, I was concerned, but my doctor told me not to worry, since it was normal, though I don't know if I mentioned the stomach pain, just the burning, itchy skin. I eventually stopped taking it, but am now taking it again, trying to find a dosage that doesn't result in intense discomfort. With the flush, I can hardly breathe, anything touching my skin hurts, and my stomach feels like I haven't eaten for a day or two.