What Is Niacin And How Does It Work?

Niacin, or vitamin B-3, is a general term that refers to nicotinic acid and its derivatives. Three main forms of niacin are currently available on the market:

• nicotinic acid
  
• nicotinamide
  
• inositol hexaniacinate
  

All of these forms of niacin are available over the counter in different doses, either by themselves or in a multivitamin. Only nicotinic acid is available as a prescription under the trade name Niaspan.

Nicotinic Acid

Nicotinic acid, or vitamin B3, is a form of niacin that has been shown to affect all aspects of the lipid profile, lowering LDL cholesterol by 15% to 25%, lowering triglycerides by 20% to 50%, and raising HDL cholesterol by 15% to 30%. The mechanism by which it does this is not known. However, previous studies have noted that nicotinic acid reduces the amount of LDL and VLDL cholesterol made by the liver. Nicotinic acid is also associated with some undesirable side effects, such as:

• flushing
  
• itching
  
• changes in blood glucose
  
• gastrointestinal upset
  
• hot flashes
  
• palpitations
  

These side effects seem to correlate with dosage strength and may be reduced if you are taking a time-released form of nicotinic acid. These symptoms typically disappear over a week or so, as your body is adjusting to the medication. However, the symptoms can be so severe in some patients to the point that they discontinue taking this form of niacin.

This form of niacin is available over the counter and as a prescription. Additionally, nicotinic acid is also available in a couple of formulations. In the immediate-release product, nicotinic acid is introduced into the body at one time. The sustained-release product, however, introduces nicotinic acid into the body gradually in an attempt to reduce side effects.

Nicotinamide and Inositol Hexaniacinate

Nicotinamide and inositol hexaniacinate are two other commercially-available forms of niacin that were also designed to reduce the flushing and itching associated with niacin, yet still retain their cholesterol-lowering ability. Although the little studies that are available about these products show that they do reduce the flushing associated with niacin, the results of these studies also are mixed concerning their ability to lower cholesterol.

_Sources:

Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (PDF), July 2004, The National Institutes of Heath: The National Heart, Lung, and Blood Institute.

Norris RB. Flush-free niacin:dietary supplement may be benefit-free. Prev Cardiol. 2006;9(1):64-65.