Few ingredients have earned their ubiquity in skincare as genuinely as niacinamide. A water-soluble form of Vitamin B3, it appears across every price point and product category — from £3 pharmacy toners to £80 clinical serums — and the scientific support behind it is unusually robust for an over-the-counter ingredient. If you have ever wondered why Korean beauty brands almost universally include it in their formulations, this article explains exactly what it does, who it suits, and where the marketing oversteps the science.

What niacinamide actually does

Niacinamide works through several distinct mechanisms, which is why it appears in products targeting concerns as different as hyperpigmentation, large pores, oiliness, and barrier damage. Its primary function at a cellular level is as a precursor to NAD+ and NADP+, coenzymes essential to energy metabolism and DNA repair in skin cells. In practical terms, this means niacinamide supports the capacity of skin cells to repair and renew themselves — a benefit that compounds over time with consistent use.

In terms of visible results, peer-reviewed research — including a well-cited 2002 study by Bissett et al published in the International Journal of Cosmetic Science — demonstrates that four per cent niacinamide applied for twelve weeks significantly reduced hyperpigmentation, fine lines, and yellowing compared to vehicle control. Further studies confirm it reduces sebum production, strengthens the ceramide-rich skin barrier, and has a mild anti-inflammatory effect that can calm reactive or acne-prone skin.

"Niacinamide is one of the few ingredients that delivers meaningful results at the concentrations actually used in skincare products — typically two to ten per cent."

The ten per cent question

You will see niacinamide products marketed at concentrations ranging from two to twenty per cent. The evidence-backed sweet spot sits between four and ten per cent — the range used in most clinical studies. Formulations above ten per cent do not appear to deliver meaningfully better outcomes, and some individuals find very high concentrations cause temporary flushing. If you are new to niacinamide, starting at five per cent is a sensible approach.

Does it clash with Vitamin C?

An enduring myth holds that niacinamide and Vitamin C cannot be used together because they form a compound called niacin that causes flushing. At cosmetic concentrations and typical skin temperatures, the conversion rate is negligibly small. Using a niacinamide serum and a Vitamin C serum in the same routine is unlikely to cause problems for the vast majority of users. A reasonable approach is to apply Vitamin C first, allow it to absorb, then apply niacinamide — primarily because each works best at a different pH.

Who benefits most

Niacinamide is one of the most versatile ingredients in skincare because it tolerates well across most skin types, including sensitive and rosacea-prone skin. Those with combination or oily skin tend to notice the most dramatic results from sebum regulation — often within four to six weeks. For hyperpigmentation and post-inflammatory marks, consistent use over three to six months typically produces visible fading. For those with a compromised skin barrier, niacinamide's ability to stimulate ceramide production makes it a particularly useful daily inclusion.

SkinRevu Verdict  Genuinely worth including in most routines. The evidence base is solid, the tolerance profile is excellent, and the price-to-efficacy ratio is hard to beat — particularly in K-beauty formulations that typically use it at clinically-supported concentrations alongside complementary actives.