Disclaimer here: I am a librarian, not a health professional. This means that I am good at looking things up. I am not responsible for what uses you make of this info.
Here is the National Library of Medicine's page on Niacin:
https://medlineplus.gov/druginfo/meds/a682518.htmlAll supplement-taking folks need to check for reputable info, not just what they heard on an RV forum or TV or wherever. There is a supplement and drug info database at
https://medlineplus.gov/druginformation.html. Access is free, and the language is usually not too difficult to understand.