COSRX The Niacinamide 15 Serum
Ingredients and claims, checked
Last checked September 23, 2026
Premium for serums
Other stores (2)
- Olive Young USShips to the US
- Korean brand site (in Korean)
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What is it like at a glance?
What is this product?
- What to expect
- It's made for clearer-looking skin and less visible pores.
- Key ingredients
- Niacinamide 15%, Acetyl Glucosamine, Zinc PCA
- When
- Morning and evening
A serum that adds targeted ingredients after toner. It comes in a 20 ml size and features Niacinamide 15%.
Who is it for?
Less suited to
- Sensitive skin
What's good?
Good points
- Contains Niacinamide 15%
How do you use it?
- Pairs well with
- A broad-spectrum sunscreen of SPF 30 or higher in the morning
- A moisturiser on top
- Don't combine with
- A second high-strength niacinamide leave-on in the same routine
What is in it?
The full ingredient list as the brand publishes it, in the printed order. Tap a name to read about that ingredient.
Key ingredient
- Water
- Pentylene Glycol
- Niacinamide
- Butylene Glycol
- Acetyl Glucosamine
- 1,2-Hexanediol
- Zinc PCA
- Trehalose
- Xanthan Gum
- Pullulan
- Allantoin
- Ethylhexyl-glycerin
- Sodium Phytate
- Citric Acid
- Tocopherol
Ingredients with no mark are ones we found nothing notable about, and when marks overlap on one ingredient we show the caution first.
What the claims add up to
- Only partly backed:
- less visible pores (amount unknown) · clearer-looking skin (amount unknown) · less shine · less visible dark spots
- Don't count on:
- firmer skin · a brighter skin tone
See each claim, checked (54)
Claims, checked
Acetyl Glucosamine + Zinc PCA
backed by evidenceNiacinamide 15%
backed by evidence#Sebum&PoreImprovement
plausible, not tested#SkinBarrierImprovement
plausible, not tested#TroubleAndMarkImprovement
plausible, not tested#SkinDrynessRelief
plausible, not testedNiacinamide is a smart ingredient that resolves various skin concerns including trouble and mark improvement, sebum & pore improvement, skin barrier improvement, and even relief of skin dryness!
plausible, not testedSebum quantity reduction
plausible, not testedOil quantity reduction
plausible, not testedSebum secretion control
plausible, not testedA light liquid formula that controls oiliness and leaves only freshness
plausible, not testedA dropper wiper that separates well from the package makes recycling easy upon disposal.
plausible, not testedRemovable sticker label* that peels off cleanly
plausible, not testedCare from sebum & pore improvement to trouble* marks all at once
partly backed+ Oil Control + Minimize Pores & Sebum
partly backedApproved by the Korean Ministry of Food and Drug Safety as a 'whitening functional certified ingredient', safety and efficacy have been proven through numerous research papers, and there are research results showing safety even at concentrations up to 20%.
partly backedNon-greasy feeling and fast absorption, usable for acne-prone skin & sensitive skin
partly backedRelieves trouble marks
partly backedFeeling that trouble marks or spots were relieved: 100%
partly backedFeeling that skin sebum and trouble improved: 100%
partly backedFeeling that skin oiliness was relieved: 100%
partly backedPigmentation improvement -15%
partly backedMark improvement -19%
partly backedRed skin -24.8%
partly backedYellow skin -11.7%
partly backed#HighStrengthTroubleSerum
partly backed*In just 4 weeks, end of worries about sebum / oil / blackheads / whiteheads! Trouble care serum
overstatedTriple complexion skin tone improvement
overstated15% optimal concentration formulation for genuinely effective care
overstatedTry it once and you'll know the definite trouble* care effect
overstatedSatisfaction with skin changes experienced by consumers over about 4 weeks: surprisingly 100%
overstatedIn just 4 weeks! Overwhelming improvement in excess sebum · oil · blackheads and whiteheads
overstated*Red sebum lines extending from both eyebrows to nose, beside nose, nasolabial folds, and chin → completely disappeared after 4 weeks
overstatedIn just 4 weeks! Marks also neatly relieved
overstatedIn just 4 weeks! From uneven reddish tone to uniform tone
overstatedElasticity and glow that fills up tautly even into pores
no supporting source foundBEAUTY & WELLNESS GLAMOUR AWARD · 2023
no supporting source foundiF DESIGN AWARD 2023
no supporting source foundBlackhead count reduction
no supporting source foundWhitehead count reduction
no supporting source foundTrouble* spot care
no supporting source foundRelieves worsening of trouble
no supporting source foundPrescription with carefully selected synergistic ingredients that maximize trouble care
no supporting source foundSebum quantity -45%
no supporting source foundOil quantity -48%
no supporting source foundBlackhead count -42%
no supporting source foundWhitehead count -50%
no supporting source foundDark skin +2.5%
no supporting source foundPatent pending (Application number 10-2021-0096102)
no supporting source foundTrouble* intensive care effect contained in one drop
nothing specific to checkA true trouble* solution must tackle from the cause to the marks
nothing specific to checkCOSRX's own solution for trouble caused by trouble
nothing specific to checkUse of niacinamide that provides comprehensive care for problem skin
nothing specific to checkClean COSRX caring for the earth
nothing specific to check
We quote each claim exactly as the brand published it, then check it against the ingredient list and the brand's own documents.
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