“Niacinamide is a multifunctional cosmetic ingredient that, at commonly used concentrations (around 2–5%), supports multiple skin concerns including fine lines, uneven tone, excess sebum, skin barrier function, acne-prone skin, and hyperpigmentation, while maintaining a favorable safety profile when properly formulated”

Randomised clinical evidence exists for topical niacinamide on each endpoint named, but at different concentrations and with different strength. Fine lines and tone: in a 12 week double blind, placebo controlled, split face study of 50 white women aged 40 to 60 with facial photoaging, 5% niacinamide in a moisturiser gave significant improvements versus the same moisturiser without it in fine lines and wrinkles, hyperpigmented spots, texture, red blotchiness and yellowing. The endpoints are appearance measures and the work was done at Procter and Gamble. Hyperpigmentation: a double blind split face trial in 27 melasma patients compared 4% niacinamide with 4% hydroquinone over 8 weeks; colorimetric assessment showed no statistical difference between the two sides, while hydroquinone's lightening was visible earlier. A separate 9 week randomised, double blind, placebo controlled study tested 4% niacinamide and 0.05% desonide for axillary hyperpigmentation. A further randomised vehicle controlled trial of 4% niacinamide plus 2% N-acetyl glucosamine reported significantly lower spot area fraction at weeks 6 and 8. Acne: a randomised double blind trial allocated 80 patients with moderate inflammatory facial acne to 4% nicotinamide or 1% clindamycin gel twice daily; both improved acne, with nicotinamide performing better in oily skin and clindamycin better in non-oily skin. Another double blind randomised trial compared 5% nicotinamide gel with 2% clindamycin gel in mild to moderate acne. Sebum: two trials of a 2% niacinamide moisturiser, 100 Japanese subjects (double blind, placebo controlled, parallel groups) and 50 US subjects, reported significantly lowered sebum excretion rate versus placebo at 2 and 4 weeks. Safety: the CIR Expert Panel concluded niacinamide and niacin are safe as used in cosmetics. Clinical testing produced no stinging up to 10%, no irritation in use tests up to 5%, and no irritancy in a 21 day cumulative irritation test up to 5%. The Panel recorded that these ingredients are not significant skin irritants, sensitisers or photosensitisers, that some formulations were marginal to slight ocular irritants while others were not, and that niacinamide is not carcinogenic alone though it can modulate tumour induction by certain established carcinogens at doses high relative to cosmetic use concentrations. At the time of that report, reported use concentrations ran from 0.0001% in night preparations to 3% in body and hand creams, lotions, powders and sprays. The cited source: the publisher of the CosmEthically ACTIVE Journal states on its own pages that the publication is not a scientific journal and is intended for a wider audience, and that the same association runs the CosmEthically ACTIVE certification. The specific article cited in the post (Berglez P, Cos ACTIVE J. 2025;3:22-29) was not retrievable.