Nicotinamide (INN, BAN UK[2]) or niacinamide (USAN US) is a form of vitamin B3 found in food and used as a dietary supplement and medication.[3][4][5] As a supplement, it is used orally (swallowed by mouth) to prevent and treat pellagra (niacin deficiency).[4] While nicotinic acid (niacin) may be used for this purpose, nicotinamide has the benefit of not causing skin flushing.[4] As a cream, it is used to treat acne, and has been observed in clinical studies to improve the appearance of aging skin by reducing hyperpigmentation and redness.[5][6] It is a water-soluble vitamin.
Nicotinamide is the preferred treatment for pellagra, caused by niacin deficiency.[4]
Acne
Nicotinamide cream is used as a treatment for acne.[5] It has anti-inflammatory actions, which may benefit people with inflammatory skin conditions.[18]
Nicotinamide increases the biosynthesis of ceramides in human keratinocytes in vitro and improves the epidermal permeability barrier in vivo.[19] The application of 2% topical nicotinamide for 2 and 4 weeks has been found to be effective in lowering the sebum excretion rate.[20] 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.[21]
Skin cancer
Nicotinamide at doses of 500 to 1000mg a day decreases the risk of skin cancers, other than melanoma, in those at high risk.[22]
Side effects
Nicotinamide has minimal side effects.[7][8] At very high doses above 3g/ day acute liver toxicity has been documented in at least one case.[7] Normal doses are safe during pregnancy.[9]
NAD+ acts as an electron carrier that mediates the interconversion of energy between nutrients and the cell's energy currency, adenosine triphosphate (ATP). In oxidation-reduction reactions, the active part of the cofactor 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.[34]
When one mole of NADH is oxidized, 158.2kJ of energy will be released.[34]
Biological role
Nicotinamide occurs as a component of a variety of biological systems, including within the vitamin B family and specifically the vitamin B3 complex.[10][11] 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.[32] The NADPH/NADP+ structures have the same ring, and are involved in similar biochemical reactions.
Nicotinamide can be methylated in the liver to biologically active 1-Methylnicotinamide when there are sufficient methyl donors.
Food sources
Nicotinamide occurs in trace amounts mainly in meat, fish, nuts, and mushrooms, as well as to a lesser extent in some vegetables.[35] It is commonly added to cereals and other foods. Many multivitamins contain 20–30mg of vitamin B3 and it is also available in higher doses.[36]
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.[39]
Nicotinamide has been investigated for many additional disorders, including treatment of bullous pemphigoid nonmelanoma skin cancers.[40]
Nicotinamide may be beneficial in treating psoriasis.[41]
There is tentative evidence for a potential role of nicotinamide in treating acne, rosacea, autoimmune blistering disorders, ageing skin, and atopic dermatitis.[40] Nicotinamide also inhibits poly(ADP-ribose) polymerases (PARP-1), enzymes involved in the rejoining of DNA strand breaks induced by radiation or chemotherapy.[42] ARCON (accelerated radiotherapy plus carbogen inhalation and nicotinamide) has been studied in cancer.[43]
Research has suggested nicotinamide may play a role in the treatment of HIV.[44]
^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.
^World Health Organization (2021). World Health Organization model list of essential medicines: 22nd list (2021). Geneva: World Health Organization. hdl:10665/345533. WHO/MHP/HPS/EML/2021.02.
^Niren NM (January 2006). "Pharmacologic doses of nicotinamide in the treatment of inflammatory skin conditions: a review". Cutis. 77 (1 Suppl): 11–6. PMID16871774.
^Tanno O, Ota Y, Kitamura N, Katsube T, Inoue S (September 2000). "Nicotinamide increases biosynthesis of ceramides as well as other stratum corneum lipids to improve the epidermal permeability barrier". The British Journal of Dermatology. 143 (3): 524–31. doi:10.1111/j.1365-2133.2000.03705.x. PMID10971324. S2CID21874670.
^Draelos ZD, Matsubara A, Smiles K (June 2006). "The effect of 2% niacinamide on facial sebum production". Journal of Cosmetic and Laser Therapy. 8 (2): 96–101. doi:10.1080/14764170600717704. PMID16766489. S2CID36713665.
^Rolfe HM (December 2014). "A review of nicotinamide: treatment of skin diseases and potential side effects". Journal of Cosmetic Dermatology. 13 (4): 324–8. doi:10.1111/jocd.12119. PMID25399625. S2CID28160151.
^Ranaweera A (2017). "Nicotinamide". DermNet New Zealand (www.dermnetnz.org). DermNet New Zealand Trust. Archived from the original on 25 March 2017. Retrieved 30 June 2017.
^British Pharmacopoeia Commission Secretariat (2009). Index, BP 2009(PDF). Archived from the original(PDF) on 22 July 2011. Retrieved 4 February 2010.
^Kaanders JH, Bussink J, van der Kogel AJ (December 2002). "ARCON: a novel biology-based approach in radiotherapy". The Lancet. Oncology. 3 (12): 728–37. doi:10.1016/s1470-2045(02)00929-4. PMID12473514.