More on niacin: No flush, no good
The term niacin comes from nicotinic acid vitamin, but it’s used to refer to both nicotinic acid and a closely related molecule, nicotinamide. Both nicotinic acid and nicotinamide are necessary to prevent pellagra, a disease that causes skin inflammation, diarrhea, and dementia. After they were first discovered in the 1930s, nicotinic acid and nicotinamide were known for a time as the pellagra-preventing vitamins.
In the mid-1950s, researchers discovered that nicotinic acid — but not nicotinamide — was remarkably effective at lowering cholesterol and triglyceride levels. We talk about niacin having these good effects, partly because niacin appears on ingredient and nutrition labels, but strictly speaking, it’s just nicotinic acid that does.
Nicotinic acid — but again, not nicotinamide — also triggers the release of prostaglandins that cause flushing, a more severe and sometimes uncomfortable form of the blushing that occurs when we’re embarrassed. So researchers have looked for ways to chemically package nicotinic acid so it retains its cholesterol- and triglyceride-lowering effects but doesn’t turn people red-faced.
Inositol hexaniacinate looked like it might be the answer. It’s a combination of six molecules of nicotinic acid (thus hexaniacinate) and one molecule of inositol. The hope was that it would break down slowly so the nicotinic acid would hit the bloodstream gradually and not cause flushing.
Results in rabbits were promising. But in a number of trials conducted in people in the late 1970s, the compound had little, if any, effect on cholesterol. Other research has shown peak levels of nicotinic acid in the blood from inositol hexaniacinate were a tiny fraction of those seen after a person took crystalline or sustained-release forms of niacin.
The niacin in every no-flush product we’ve seen comes as inositol hexaniacinate. The no-flush claim is true enough, but the credible evidence we know of suggests that you aren’t likely to see the cholesterol or triglyceride benefits, either. For a niacin product to have an effect on cholesterol and triglyceride levels, the niacin must be in the form of nicotinic acid — not inositol hexaniacinate or nicotinamide.