(Excerpt from Niacin the Real Story.)
Forms of Niacin and How they Differ in Action.
Derivatives of niacin (nicotinic acid) have been examine for their ability to alter lipid levels as well as niacin does.
Niacin lowers cholesterol, elevates high-density lipoprotein (HDL) cholesterol, and reduces the ravages of heart disease, but causes flushing when it is first taken. The flushing reaction dissipates in time and in most cases is gone or very minor within a matter of weeks. Niacinimide, which is not a vasodilator, does not produce a flush, but is has no effect on blood fats (lipids). Inositol hexaniacinate will lower cholesterol without the flushing side effect, but does not do so as well as plain niacin.
Another major difference between niacin and Niacinimide is that niacin normalizes blood lipid values. It lowers 'bad' cholesterol, elevates 'good' cholesterol, lowers triglycerides, lowers lipoproteins (a) Lp(a) is considered a risk factor for heart disease, and lowers the anti-inflammatory factor C-reactive protein. It therefore is the best substance known for these important therapeutic effects. Niacinimide has none of these properties.
The other common form of niacin is nicotinamide, known more commonly as niacinimide. Both niacin and niacinimide forms are precursors to the active anti-pellagra factor NAD (nicotinamide adenine dinucleotide). A third form of vitamin B3, nicotinamide riboside, was discovered in 2004, and little is known about it. Your body uses NAD (with a hydrogen, it is NADH) in over 450 biochemical reactions , most of which are involved in anabolic and catabolic reactions. Most people tend to associate NAD with glycolysis (sugar breakdown) and ATP (energy production). However, NAD is involved with many other reactions as a cofactor, including either the synthesis (anabolism) or the breakdown (catabolism) of just about every molecule our cells make: steriods, prostaglandins, and enzymes. NAD is involved in cell signaling and assists in ongoing repair of your DNA. There are several important reactions where it functions as a substrate for the enzymes PARP, Sirtuin, and IDO.
If there is a flush from niacinimide, it is very unpleasant. (I've experienced it, and its terrible: severe dizziness, tingling limbs, nausea, and it stuck with me for four hours. The dose? Only 500 mg.--Gimpy)
Niacinimide is more likely to cause nausea at long-term, medium-high dosages than are the other forms of B3. By medium-high we mean several thousand mg per day. Niacin and inositol hexaniacinate generally do not cause nausea unless the dose is extremely high, on the order of tens of thousands of mg per day. No one would need to take that excessive amount of B3, and no one should. And just to be sure, nausea indicates overdose. On the other hand, niacinimide has been successfully used at maintained doses of several thousand mg per day by Dr. William Kaufman to treat arthritis (see chapter 7) He reported virtually zero side effects.
For those few who cannot tolerate niacin, there is an option of using inositol hexaniacinate. This preparation has most of the therapeutic advantages of niacin and none of the side effects. It is available in health food stores as 'no flush niacin.' It costs perhaps three times as much as 'regular' niacin, but this is still much better than the cheapest statins.
Inositol hexaniacinate is an ester of inositol and nicotinic acid. It is sometimes called inositol hexannicontinate. The ester is broken down slowly in the body. It is about as effective as nicotinic acid. There is very little flushing, gastrointestinal distress, or other side effects. Inositol does have a function in the body as a messenger molecule and may add something to the therapeutic properties of nicotinic acid. Remember that niacin (nicotinic acid) and nicotine have no physiological properties in common.
And with this, I'm done for the evening.