Anyone suffering from Restless Leg Syndrome, big caution. This drug, like SSRIs, can make the condition worse and/or trigger it.
Be careful with advice on the internet (for all you know, I'm a dog). Iron overload is harmful. Niacin may cause a "flush" which is transient, but feels like your skin is sunburned for 20-30 minutes. Do your own research about amounts etc. Consult a medical professional if you don't feel qualified to do your own research. This is not medical advice, just some random info. (Though, it helped me a lot)
Counter-point? https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4733501/