What is the differance between niacinamide and flush-free niacin?

Good question.: The niacinamide form of Niacin is a b vitamin (it's in your cereal) which does not lower cholesterol like the nicotinic acid form of niacin. Since nicotinic acid causes flushing, makers have tried changing the formulation so it's "flush-free" but will still lower cholesterol. The active ingredient of your cholesterol-lowering Niacin preparation should always be nicotinic acid.