T. J. Clark Liquid Vitamin B3. Niacin or Vitamin B3 is more commonly known as nicotinamide in the biochemical community and plays an important role in the biosynthesis of pyridine nucleotides. This nitrogen heterocyclic biochemical is combined in vivo with the nucleotide adenosine to form nicotinamide adenine dinucleotide (NAD), which serves as a soluble electron carrier in biochemical reactions.

Clinically, niacin serves to maintain normal function of the digestive system, helps to reduce cholesterol levels, and serves to reduce dizziness and ringing in the ears. Niacin has been tested for its effects on cardiovascular-disease risk factors in a number of major trials. In the largest of these, the effect of niacin on cardiovascular endpoints was studied. Symptoms associated with niacin deficiency include general weakness and fatigue, loss of appetite, dermatitis, skin lesions, a swollen tongue, diarrhea, mental confusion, irritability, and, when the central nervous system is affected, depression and mental disturbances. Mega doses of niacin have been used experimentally in the treatment of schizophrenia, although no experimental proof has been produced to show its efficacy. In large amounts it reduces levels of cholesterol in the blood, and it has been used extensively in preventing and treating arteriosclerosis. Large doses over long periods cause liver damage.