Niacinamide (also called nicotinamide) is the active, water-soluble form of vitamin B3. Unlike niacin, it doesn't cause a flushing response, which makes it one of the most tolerated actives in skincare. It works across multiple pathways simultaneously, which is rare for a single ingredient, and has a research base that spans decades across dermatology, oncology, and metabolic medicine.
Topically, it's used for:
Mechanism of action
Niacinamide is a precursor to NAD+ and NADP+, coenzymes involved in hundreds of cellular reactions including DNA repair, energy metabolism, and oxidative stress regulation. In skin specifically, it works through several distinct pathways.
It inhibits melanosome transfer from melanocytes to keratinocytes, which is how it addresses pigmentation without actually blocking melanin synthesis (the approach most brightening actives take). It also upregulates ceramide synthesis, strengthening the stratum corneum and reducing transepidermal water loss. Sebum regulation appears to come from its anti-inflammatory action and influence on sebocyte activity, not from any drying mechanism.
One large controlled trial found 4% niacinamide significantly outperformed 1% clindamycin for acne over 8 weeks, which is notable because clindamycin is a prescription antibiotic. For pigmentation, studies consistently show measurable reduction in melanin transfer at concentrations of 2–5%, with results visible around the 4-week mark and continuing to improve through 8–12 weeks.
Topical