Niacin, a member of the B Vitamin family, is water-soluble and highly absorbable. Niacin is referred to as B3 and includes nicotinic acid, nicotinic acid, and nicotinamide. Niacin is found in high concentrations in red meat, poultry, fish, legumes and yeast. Niacin is involved in the maintenance of total cholesterol levels. It obstructs the free fatty acid release from the tissue as well as cyclic AMP accumulation. Niacin works to slow down the liver's synthesis of LDL and VLDL. Niacin is also involved in vasodilatory activities. Niacin, importantly, can be converted into niacinamide. Niacinamide is involved in lipid metabolization, tissue respiration, and glycogenolysis as well as being a component of several coenzymes which act as hydrogen carriers. Niacin and Niacinamide are closely connected and often grouped together due to their relationship
Niacin has negative interactions with several drugs and they should not be combined. Niacin may interfere with blood glucose levels and should not be used with antidiabetes drugs, nor should it be used with isoniazid, transdermal nicotine, or HMG-CoA reductase inhibitors. These combinations decrease the effectiveness of the drugs and increase the risk of side effects.
As with all drugs and supplements, consult a health care professional before use. Niacin is well tolerated by most people, in recommended dosage but may have some minor side effects for some people. These side effects include flushing, headache, and a burning/tingling/itching sensation. If high doses are consumed, side effects may include added symptoms of pruritus, nausea, bloating, flatulence, vomiting, heartburn, diarrhea, hypotension, dizziness, tachycardia, arrhythmias, syncope, headache, and impaired vision.