
The Niacinamide 15 Serum — Reddit Reviews
by COSRX
Updated October 6, 2026
15% niacinamide for oil control and smoother-looking pores; can sting.
What the community says
Redditors use this for oil control, pores, and post-acne mark fading, with a lightweight feel that layers easily. The catch is the 15% niacinamide hit can sting reactive skin, so sensitive folks often start slow.
What this means for you
What people love
- 15% niacinamide for oil control
- Lightweight, fast-absorbing layer
- Helps calm inflammation and tighten skin
Watch out for
Product details
Skin type data limited
What the science says
Acne
Some evidence
Niacinamide: 6 studies tested it on its own. See all 17 studies
Hyperpigmentation
Some evidence
Niacinamide: 5 studies tested it on its own. See all 24 studies
What the studies found
- All of these studies found niacinamide helped fade dark spots or patches
- Niacinamide 5% faded dark spots more than a placebo in studies of sun-damaged skin and dark patches
- Used with salicylic acid peels, niacinamide improved dark patches more than peels alone
- A niacinamide mix faded dark spots better than niacinamide alone in one study
- One study found the fading effect reversed after niacinamide was stopped
Studied at 2–10%this product: 15%
Skin Barrier
Not proven yet
Few or mixed studies. This claim isn't established.
Niacinamide: 1 study tested it on its own. See all 17 studies
Research context, not treatment advice. Studies are about the ingredient, not necessarily this exact product.
Real Reddit threads — 10 mentions across 7 threads
COSRX The Niacinamide 15 Serum on Reddit, in one place — 7 threads from r/koreanskincare, r/AsianBeauty and 1 more, summarized.
“Niacinimide serum (night only)”
Positive
“I am currently using a COSRX regimen and it’s completely transformed my skin.”
Positive
“I have almost no visible acne and my skin feels so smooth, tight, but hydrated.”
Positive
“After I wash my face, I put a tiny bit of Cosrx Niacinamide & Zinc Serum.”
Positive
“It cuts down the oil that messes up your makeup later.”
Positive
“Thai here 👋 After I wash my face, I put a tiny bit of Cosrx Niacinamide & Zinc Serum.”
Positive
“It burned my skin but my skin tolerates Cosrx niacinamide 15.”
Mentioned
“So not sure about the formulation.”
Mentioned
“Cosrx niacinamide 15”
Mentioned
“COSRX The Niacinamide 15 Serum”
Positive
“The serum is what made a big difference in acne and appearance of pores for me”
Positive
“but every step is important”
Positive
“Recommended: COSRX 15% Niacinamide Face Serum”
Positive
“It absorbs fast and feels lightweight.”
Positive
“I can use it every day with no problems.”
Positive
“COSRX 15% Niacinamide Face Serum (websites I mentioned, Amazon and TJ Maxx/Marshalls).”
Mentioned
“There are more expensive ones you can try if you're not feeling the DT.”
Mentioned
“A lot of people who describe their skin the way you describe yours experience benefits from a niacinamide serum.”
Mentioned





