Niacinamide — the amide form of vitamin B3, and a staple of nearly every serum shelf from Chelsea drugstores to department-store counters — has evidence behind two concentrations in particular: 5 percent, which a 2002 study in the British Journal of Dermatology found reduced hyperpigmentation, and 2 percent, which reduced sebum production in a 2006 trial in the Journal of Cosmetic and Laser Therapy. The label on the bottle tells you the ingredient; it usually doesn't tell you which concentration, and the evidence lives in the number.
New York Health & Beauty publishes information, not medical advice. Skin conditions and dermatologic treatments belong with a clinician, and nothing here is a regimen of the site's own.
What is niacinamide, chemically speaking?
Niacinamide is a water-soluble form of vitamin B3 that the skin uses as a precursor to nicotinamide adenine dinucleotide, a coenzyme involved in cellular energy metabolism. Unlike niacin, its close chemical relative, it doesn't cause the flushing niacin is known for, which is why it's the form formulated into leave-on products. It's also stable in aqueous solution and tolerates a wide pH range — two practical reasons it appears in everything from toners to sunscreens.
In formulation context, it pairs easily with humectants and works across the routine. The chemistry is not in dispute; the questions start at what it does to living skin.
Does niacinamide actually fade dark spots?
At 5 percent, there is controlled-trial evidence. A randomized study by Hakozaki and colleagues, published in the British Journal of Dermatology in 2002, found that a 5 percent niacinamide moisturizer reduced hyperpigmentation and increased skin lightness after four weeks compared with vehicle, in a study population of adult women. The mechanism proposed was inhibition of melanosome transfer from melanocytes to keratinocytes.
The qualifications matter as much as the finding. The trial measured modest changes over weeks, not an evening-out of pigment; it was funded by a cosmetics company, which the paper discloses; and it does not address post-inflammatory hyperpigmentation in deeper skin tones as a separate question. The 2002 result is real support, and it is support for 5 percent in a moisturizer base — not for every concentration in every vehicle.
What does the evidence say about oil and pores?
For sebum, the number is 2 percent. A 2006 study by Draelos and colleagues in the Journal of Cosmetic and Laser Therapy found 2 percent niacinamide reduced sebum production rates in subjects with oily skin over four weeks, with reductions in facial shine. The same paper reported the effect on casual sebum levels, a softer measure. Here again, brand-affiliated funding is disclosed in the research.
Pore appearance is one step further down the evidence chain: published studies on pore visibility are smaller and shorter, often relying on subjective grading, and the results should be read as preliminary rather than settled. The sebum result is the load-bearing one.
What don't we know?
Three gaps stand out. Concentration-response above 5 percent is poorly characterized, and higher percentages on the shelf are riding on extrapolation, not on trials at those strengths. Long-term use beyond the weeks-long trial windows has not been well studied for pigment outcomes. And combination evidence — niacinamide alongside retinoids, vitamin C, or exfoliating acids in real routines — is mostly formulation chemistry, not controlled skin-outcome research.
The ingredient earns its shelf space. The elegant skepticism is simply this: what the studies support is 5 percent for pigment and 2 percent for sebum, in the bases tested, over the windows measured. A product citing niacinamide without a concentration is asking you to buy the ingredient and imagine the study.