Nicotinamide is the preferred treatment for pellagra, caused by niacin deficiency. While niacin may be used, nicotinamide has the benefit of not causing skin flushing.
Nicotinamide cream is used as a treatment for acne. It has anti-inflammatory actions, which may benefit people with inflammatory skin conditions.
Nicotinamide increases the biosynthesis of ceramides in human keratinocytes in vitro and improves the epidermal permeability barrier in vivo. The application of 2% topical nicotinamide for 2 and 4 weeks has been found to be effective in lowering the sebum excretion rate. Nicotinamide has been shown to prevent Cutibacterium acnes-induced activation of toll-like receptor 2, which ultimately results in the down-regulation of pro-inflammatory interleukin-8 production.
Nicotinamide at doses of 500 to 1000mg a day decreases the risk of skin cancers, other than melanoma, in those at high risk.
NAD+ acts as an electron carrier that helps with the interconversion of energy between nutrients and the cell's energy currency, adenosine triphosphate (ATP). In oxidation-reduction reactions, the active part of the coenzyme is the nicotinamide. In NAD+, the nitrogen in the aromatic nicotinamide ring is covalently bonded to adenine dinucleotide. The formal charge on the nitrogen is stabilized by the shared electrons of the other carbon atoms in the aromatic ring. When a hydride atom is added onto NAD+ to form NADH, the molecule loses its aromaticity, and therefore a good amount of stability. This higher energy product later releases its energy with the release of a hydride, and in the case of the electron transport chain, it assists in forming adenosine triphosphate.
When one mole of NADH is oxidized, 158.2 kJ of energy will be released.
Nicotinamide occurs as a component of a variety of biological systems, including within the vitamin B family and specifically the vitamin B3 complex. It is also a critically important part of the structures of NADH and NAD+, where the N-substituted aromatic ring in the oxidised NAD+ form undergoes reduction with hydride attack to form NADH. The NADPH/NADP+ structures have the same ring, and are involved in similar biochemical reactions.
Nicotinamide occurs in trace amounts mainly in meat, fish, nuts, and mushrooms, as well as to a lesser extent in some vegetables. It is commonly added to cereals and other foods. Many multivitamins contain 20-30 mg of vitamin B3 and it is also available in higher doses.
A 2015 trial found nicotinamide to reduce the rate of new nonmelanoma skin cancers and actinic keratoses in a group of people at high risk for the conditions.
Nicotinamide has been investigated for many additional disorders, including treatment of bullous pemphigoid nonmelanoma skin cancers.
Niacinamide may be beneficial in treating psoriasis.
There is tentative evidence for a potential role of nicotinamide in treating acne, rosacea, autoimmune blistering disorders, ageing skin, and atopic dermatitis. Niacinamide also inhibits poly(ADP-ribose) polymerases (PARP-1), enzymes involved in the rejoining of DNA strand breaks induced by radiation or chemotherapy. ARCON (accelerated radiotherapy plus carbogen inhalation and nicotinamide) has been studied in cancer.
^World Health Organization (2019). World Health Organization model list of essential medicines: 21st list 2019. Geneva: World Health Organization. hdl:10665/325771. WHO/MVP/EMP/IAU/2019.06. License: CC BY-NC-SA 3.0 IGO.
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^Snaidr VA, Damian DL, Halliday GM (February 2019). "Nicotinamide for photoprotection and skin cancer chemoprevention: A review of efficacy and safety". Experimental Dermatology. 28 Suppl 1: 15-22. doi:10.1111/exd.13819. PMID30698874.
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