COSRX The Niacinamide 15 Serum: What It Is, What's Inside, and Who It's For
A fast-absorbing, fragrance-free serum with 15% niacinamide and Zinc PCA, formulated for oily, combination, and acne-prone skin.
COSRX The Niacinamide 15 Serum is a lightweight, unscented serum built around a high concentration of niacinamide and Zinc PCA. It targets excess sebum, enlarged pores, and post-acne marks. It absorbs quickly, layers well under moisturizer, and works for oily, combination, acne-prone, and sensitive skin types.
Who This Serum Is For
If your main concerns are shine, clogged pores, and the dark marks left behind after breakouts, COSRX The Niacinamide 15 Serum is worth a close look. It's formulated specifically for oily, combination, and acne-prone skin, and it also suits sensitive skin — the formula is fragrance-free. If you are pregnant, breastfeeding, recovering from a procedure, on prescription skincare or managing multiple allergies, check the brand's current guidance and ask your doctor first.
That said, the 15% niacinamide concentration is on the higher end, so a patch test before full facial use is always a good idea.
What It Is and How It Feels
This is a serum in liquid form — genuinely lightweight, not a gel-cream or a hybrid. A few drops spread easily across the skin and absorb quickly without leaving any residue or heaviness. There's no scent at all, which matters if your skin reacts to fragrance or if you're layering several products and don't want competing smells.
The finish after absorption is clean and slightly matte, which makes it a natural fit for anyone who finds that most serums add unwanted slip or shine to the skin before the rest of the routine goes on.
The Ingredients That Matter
Niacinamide at 15% is the headline here. The brand formulates it at this concentration to help regulate sebum production and reduce the visible size of pores over time, as well as to address post-acne marks.
Zinc PCA works alongside the niacinamide with a focus on sebum regulation. It's a form of zinc bonded with pyrrolidone carboxylic acid, and it's commonly paired with niacinamide in Korean serums designed for oily and breakout-prone skin.
Allantoin is included to help soothe the skin — useful in a formula aimed at acne-prone or reactive complexions that may already be dealing with irritation.
