Niacinamide
Also known as Nicotinamide, Vitamin B3 (amide form), Pyridine-3-carboxamide, Nicotinic acid amide, 3-Pyridinecarboxamide
“CIR Expert Panel says: safe as used in cosmetics.”
Niacinamide (nicotinamide; pyridine-3-carboxamide; vitamin B3 amide form; CAS 98-92-0; C6H6N2O) is the amide form of vitamin B3 and a precursor to NAD+ and NADP+, which are cofactors in cellular energy metabolism, DNA repair, and redox signaling. In cosmetic formulations it functions as a multi-target active ingredient, typically used at 2-10% concentration. The Cosmetic Ingredient Review Expert Panel assessed niacinamide and niacin together and concluded that both are safe as used in cosmetics (Final Report of the Safety Assessment of Niacinamide and Niacin, Int J Toxicol 24(Suppl 5):1-31, 2005; PMID 16596767). Clinical testing found no stinging sensation at concentrations up to 10%, no irritation in use tests up to 5%, no cumulative irritation in 21-day patch tests, and no sensitization or photosensitization. Three well-characterized mechanisms support its use as a headline cosmetic active: (1) Hakozaki et al. (Br J Dermatol 2002, PMID 12100180) demonstrated that niacinamide reduces cutaneous pigmentation not by inhibiting melanogenesis but by suppressing transfer of melanosomes from melanocytes to keratinocytes, providing a mechanistic basis for its use in brightening and anti-hyperpigmentation products. (2) Tanno et al. (Br J Dermatol 2000, PMID 10971324) showed that nicotinamide increases biosynthesis of ceramides and other stratum corneum lipids, improving epidermal permeability barrier function and reducing transepidermal water loss. (3) Bissett et al. (Int J Cosmet Sci 2005, PMID 18492135) reported that topical niacinamide reduces yellowing, wrinkling, red blotchiness, and hyperpigmented spots in aging facial skin in a clinical vehicle-controlled trial. These effects — combined with anti-inflammatory activity and sebum regulation — make niacinamide one of the best-characterized multi-functional actives in contemporary skincare.
Melanosome transfer inhibitor: reduces cutaneous hyperpigmentation by blocking the handoff of melanosomes from melanocytes to keratinocytes (Hakozaki et al. 2002, PMID 12100180) — mechanism distinct from tyrosinase inhibition, making niacinamide complementary to other brightening actives
Barrier function enhancer: increases ceramide and stratum corneum lipid biosynthesis, reducing transepidermal water loss and improving resistance to irritants (Tanno et al. 2000, PMID 10971324)
Anti-aging clinical efficacy: topical niacinamide reduces yellowing, wrinkling, red blotchiness, and hyperpigmented spots in aging facial skin (Bissett et al. 2005, PMID 18492135)
Anti-inflammatory activity useful for rosacea and acne-prone skin; sebum regulation at higher concentrations
CIR Expert Panel concluded safe as used in cosmetics (Andersen et al. 2005, PMID 16596767) — non-irritating at concentrations up to 10% in use tests, non-sensitizing, non-photosensitizing
NAD+ / NADP+ precursor — biochemically ubiquitous vitamin with an extensive dietary and clinical safety record; one of the best-characterized multi-functional actives in contemporary skincare
- · Concentrations above 10% may cause transient flushing in some individuals via vasodilation (more pronounced with niacin/nicotinic acid than with niacinamide)
Rare reports of contact dermatitis in the patch-test literature, generally at high concentrations or in patients with multiple cosmetic allergies — not a common concern at typical 2-5% cosmetic use levels
CIR Quick Reference Table (12/2017, revised 07/2018) - Niacinamide row: Finding 'S' (Safe), Citation 'IJT 24(S5):1-31, 2005'
“Niacinamide | S | [no detail column entry] | IJT 24(S5):1-31, 2005”— QRT-122017revised072018.pdf, p. 78