Niacinamide (nicotinamide) is one of the two principal forms of the B-complex vitamin niacin (see Niacin). The term niacin is used as a collective term to refer to both nicotinamide and nicotinic acid, the other principal form of niacin, or the term is used synonymously with nicotinic acid. Nicotinamide and nicotinic acid have identical vitamin activities, but they have very different pharmacological activities.

Nicotinamide, via its major metabolite NAD++ (nicotinamide adenine dinucleotide), is involved in a wide range of biological processes including the production of energy, the synthesis of fatty acids, cholesterol and steroids, signal transduction, and the maintenance of the integrity of the genome. Nicotinic acid, in pharmacological doses, is used as an antihyperlipidemic agent. It also causes vasodilatation of cutaneous blood vessels resulting in the so-called niacin flush. Nicotinamide in pharmacological doses does not have antihyperlipidemic activity, nor does it cause a niacin-flush. There is evidence, however, that pharmacological doses of nicotinamide may prevent type 1 diabetes mellitus. Pyrazinamide, an important drug in the treatment of tuberculosis, is an analogue of and shares the same biochemical mechanism with nicotinamide.

Benefits of Niacinamide

Nicotinamide, unlike nicotinic acid, does not have significant effects on lipids, but it has been shown to be useful for some with type 1 (insulin-dependent) diabetes. There is preliminary evidence showing that it might help some with generalized granuloma annular and osteoarthritis. There is little evidence that it is helpful in rheumatoid arthritis or schizophrenia. There is a suggestion that it might aid in some cancer therapies. There is little evidence that it is useful in tinnitus.

Nicotinamide is being investigated as an agent for the possible prevention or delaying of the onset of type 1 diabetes mellitus (insulin-dependent diabetes mellitus or IDDM). The rationale for using nicotinamide to prevent type 1 diabetes mellitus is derived from human and animal studies as well as in vitro investigations. Nicotinamide has been found to prevent diabetes in alloxan- and streptozotocin-treated mice and rats and in non-obese diabetic (NOD) mice. In vitro studies have shown that nicotinamide can prevent macrophage- or interleukin-1beta-induced beta-cell damage. An intervention study in New Zealand using nicotinamide treatment showed a 50% reduction in the development of IDDM over a five-year period.

Nicotinamide has been shown to have antioxidant activity. In vitro, it has been found to inhibit protein oxidation and lipid peroxidation. It has also been found to inhibit reactive oxygen species-induced apoptosis, to inhibit phagocytic generation of reactive oxygen species, to scavenge reactive oxygen species and to inhibit the oxidative activity of nitric oxide.

Nicotinamide has demonstrated a number of anti-inflammatory activities. Nicotinamide has been shown to inhibit lipopolysaccharide-induced TNF-alpha in the mouse, in a dose-dependent manner. It is thought that this inhibition of TNF-alpha is mediated via inhibition, at the gene transcription level, of NF-Kappa B, which in turn inhibits TNF-alpha. Nicotinamide has also been shown to decrease the production of IL-12 and TNF-alpha in cultures of whole blood from prediabetic and diabetic subjects and also in healthy subjects.

Dosage and Administration

Nicotinamide is the form of niacin which is typically used for nutritional supplementation. It is also the form of niacin used in food fortification. It is available as a single ingredient product (immediate-release and sustained-release) and in multivitamin and multivitamin/multimineral products. Typical supplemental dosage ranges from 20 to 100 milligrams daily. Pre- and postnatal vitamin/mineral supplements typically deliver a dose of 20 milligrams