The Niacinamide 15 Serum — Reddit Reviews
by COSRX
Updated September 25, 2026
15% niacinamide serum for oil control, smoother texture, and calmer-looking skin; can burn.
What the community says
A lightweight niacinamide serum people use at night or before makeup for oil control and a smoother look. Redditors say it absorbs fast and can help skin feel tighter, but the 15% strength can sting reactive skin.
What this means for you
What people love
- High-dose niacinamide for oil and texture
- Lightweight, fast-absorbing finish
- Plays nicely under makeup
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
What the studies found
- Most studies found niacinamide helped acne
- Some studies found 4% niacinamide cleared acne about as well as clindamycin
- One study found 4% niacinamide improved red, sore spots, but IPL worked better
- Some research found no clear difference, and a large review said the effects were uncertain
Studied at 4–10%this product: 15%
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
- In clinical trials, 5% niacinamide faded dark spots more than a placebo
- It also helped when used with salicylic acid peels, more than peels alone
- Used on its own, it helped, but one study found a niacinamide mix worked better
- One study found the fading effect reversed after stopping niacinamide
Studied at 2–10%this product: 15%
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
“Then sunscreen and a makeup base, I’m using Maquillage Dramatic Skin Sensor Base Neo”
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
