Use of nicotinamide in dermatology

Abstract

Nicotinamide (synonym — niacinamide) is the water-soluble, amide isotype of vitamin B3, whilst niacin (synonym — nicotinic acid) is the corresponding acid isotype. It is used in dermatology for a long time. It has numerous applications, and it seems useful to make an updated review of its multiple uses.Nicotinamide is normally brought by our diet; meat and fish are very rich in niacinamide, which is less present in vegetables. The lack of this vitamin can cause pellagra, presenting with the triad of dementia, dermatitis and diarrhoea. Nicotinamide is the catalyst for multiple molecular reactions throughout the body, and is converted into several coenzymes, including nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP), which are of central importance for metabolism. NAD and NADP are the coenzymes of countless dehydrogenases involved in hydrogen transfer. Their main function is to supply hydrogen to the respiratory chain of mitochondria for oxidation and energy production. Nicotinamide increases ATP production which increases DNA repair, protecting the skin from photodamage. In solar-simulated, UV-irradiated, niacinamide-treated human HaCaT keratinocytes, an increased amount and rate of DNA excision repair was demonstrated in cells treated with nicotinamide vs. control. This review aims to describe the major dermatological disorders where nicotinamide was studied, mainly photoprotection and skin cancer prevention, deficiencies in skin barrier function — especially atopic dermatitis — pigmentation disorders, inflammatory diseases or acne. In all these indications, use of oral or topical nicotinamide is well-documented and offer interesting therapeutic perspectives. In some other cases like wound healing, bullous or pruritic disorders or cosmetic indications, the use of nicotinamide seems also promising, but less documented. This is also the case regarding the antibacterial properties of nicotinamide. This review also contemplates the side effects of nicotinamide, which appear to be low and lack of severity, permitting to conclude that nicotinamide is worth of being an important weapon in the dermatologists’ armamentarium.