It is a supplement. There is no body that collects that data.
No, "safety" is a relative term. Everything is both safe and unsafe depending on the curcumstances. I am saying that Niacin, at doses recommended by the FDA to prevent deficiency, does have some smal amount of toxicity. I think by almost anyone's definition it is safe. However, you are not talking about taking it at "RDA doses". You are discussing therapeutic doses. At these doses it's safety is comparable to other prescription medications given to treat cholesterol. They are considered generally safer than the condition they treat. However, they are dangerous enough that they should be monitored by a physician (apparently your own beloved Hoffer agrees). They probably are not safe enough to warrant being taken at therapeutic doses (i.e. gram quanbreasties which are much higher than the RDA) by a person at very low risk of cardiac disease.
You can believe anything you want. You can believe that the half of the day when the sun is shining overhead is not "day" but the rest of the world will still call it that.
Flushing is by any reasonable definition a toxicity. It is often toxic enough to cause reasonable people to accept an increased risk of cardiac disease and stroke in order to avoid it. Would you consider an MI or stroke a toxicity of elevated cholesterol? If large numbers of reasonable people think risking them is preferable to the flushing from niacin what does that say about whether niacin can be toxic?
Also, as has been pointed out to you (including references by Hoffer), flushing is not the only toxicity.
I guess you have no comment about the beta-carotine and lung cancer.
-- CBI, MD