Niacinamide

Niacinamide is the water-soluble, non-flushing form of Vitamin B3, niacin. Cosmetic chemists have used it since the 1990s, and today it is one of the most common active ingredients in Korean essences and serums. Most formulas contain 2-5%, the range actually tested in clinical studies, rather than the 10%+ concentrations some brands market as stronger.

It differs from niacin found in foods and supplements. High-dose niacin can cause skin flushing, while Niacinamide does not, which is why it became the standard cosmetic form.

Niacinamide is a precursor to NAD+ and NADH, coenzymes every skin cell needs for energy metabolism. This is the mechanical foundation for many of its benefits. In the epidermis, this energy supports the synthesis of ceramides and free fatty acids in the stratum corneum, the outermost barrier. This is why consistent use measurably reduces transepidermal water loss after several weeks.

Its brightening effect follows a different pathway from Vitamin C. Instead of blocking the enzyme that produces melanin, Niacinamide inhibits the transfer of melanosomes, the pigment-carrying packets, from melanocytes to surface cells. Less pigment reaches the visible layer, so tone appears more even without changing how much melanin the skin produces.

It also regulates sebaceous-gland activity, which underpins its reputation for pores and oil control. When the barrier is functioning well and sebum is regulated, pores look smaller because their perceived size is influenced largely by oil buildup and surrounding texture.

Oily and combination skin benefit from shine control and an improved appearance of pores. Sensitive skin benefits from barrier support and soothing. Dry skin benefits from ceramide support.

It is a suitable active for starting a routine, especially at moderate concentrations.

The rule that Niacinamide and Vitamin C cannot be combined comes from a 1960s laboratory study in which pure Niacinamide and ascorbic acid powders were heated and produced a reaction that converts Niacinamide to niacin, which can cause flushing. Modern formulas are stabilized and stored at room temperature, so this is not a practical concern for most people. Very reactive skin may feel temporary warmth when high concentrations are combined, so test them separately first.

More does not mean faster. Concentrations above roughly 10% increase the risk of stinging and redness without evidence that results arrive proportionally faster. Changes in barrier function and tone build over weeks of daily use.