I have been taking Niacin for about 3 months now and I never had flushing symptoms after the first week. Until 2 days ago I noticed my face was hot, and then my arms. When I looked I was all red and blotchy. The only thing that has changed is that I donated blood last saturday and I changed to a longer sub q needle for my HCG and B12 injection. I went from a 5/16 28 gage to a 1/2 inch 28 gage. I know alot do IM for B12 but the TRT clinic recommended sub q and when I did a search here on the forum the answer was about 1/2 and 1/2 sub q and IM. There was also mention of a deeper sub q. Could it be the B12 and niacin? I've been doing the B12 shot for 3 weeks now but tues. was my first day with the 1/2 pin and the first day I had flushing.