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COSRX The Niacinamide 15 Serum ingredients: is it worth it?
A genuinely potent brightening and oil-control serum, but 15% niacinamide is aggressive overkill for many skins—not a universally gentle daily essential.
A genuinely potent brightening and oil-control serum, but 15% niacinamide is aggressive overkill for many skins—not a universally gentle daily essential.
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The 15% niacinamide placed third is the main efficacy driver, with acetyl glucosamine providing credible complementary brightening support and zinc PCA supporting oil-control claims; humectants add hydration, while allantoin helps offset irritation. The formula has no disclosed fragrance or denatured alcohol, and its simple, water-based serum format avoids major packaging concerns, but the high niacinamide concentration can cause flushing, stinging, or breakouts in sensitive users. The efficacy score reflects strong active positioning and a coherent brightening/oil-control pairing, tempered by the fact that higher niacinamide is not automatically more effective and may reduce tolerability.
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DemythSkin rates COSRX The Niacinamide 15 Serum 3.9/5 for efficacy and 4.4/5 for safety.
ACTIVE INGREDIENTS BY TIER
Gold Standards
High clinical proof | Skin-transformativeReliable
Proven resultsPotent
Developing evidenceOverhyped | Marketing
Hype | Limited dataDocumented Irritants
Evidence-backed flagFORMULATION BASE (8)⌄
FULL INGREDIENT LIST⌄
Water, Pentylene Glycol, Niacinamide(15%), Butylene Glycol, Acetyl Glucosamine, 1,2-Hexanediol, Zinc PCA, Trehalose, Xanthan Gum, Pullulan, Allantoin, Ethylhexylglycerin, Sodium Phytate, Citric Acid, Tocopherol
WHAT EACH INGREDIENT DOES (15)⌄
- Water
- Solvent and formula base
- Pentylene Glycol
- Humectant and solvent
- Niacinamide(15%)
- Brightening and sebum-regulating active
- Butylene Glycol
- Humectant and solvent
- Acetyl Glucosamine
- Skin-conditioning brightening support
- 1,2-Hexanediol
- Humectant and preservative booster
- Zinc PCA
- Sebum-regulating skin conditioner
- Trehalose
- Humectant and moisture binder
- Xanthan Gum
- Viscosity-controlling thickener
- Pullulan
- Film-forming texture agent
- Allantoin
- Soothing skin-conditioning agent
- Ethylhexylglycerin
- Preservative booster and conditioner
- Sodium Phytate
- Chelating formula stabilizer
- Citric Acid
- pH-adjusting acid
- Tocopherol
- Antioxidant skin conditioner
EXTERNAL CITATIONS
Niacinamide: Well-studied topical ingredient for barrier support, uneven tone, and sebum regulation
Acetyl Glucosamine: Evidence-supported skin-conditioning and pigmentation-support ingredient
Zinc PCA: Sebum-regulating cosmetic ingredient with supportive evidence for oily skin
Allantoin: Established soothing and skin-protective cosmetic ingredient
DISCLAIMER: THIS ANALYSIS IS FOR INFORMATION ONLY. NOT MEDICAL ADVICE. AI-GENERATED DATA BASED ON PUBLICLY AVAILABLE INGREDIENT LISTS. VERIFY WITH A MEDICAL PROFESSIONAL.
A cheaper serum with a similar formula
A partial ingredient match (39%), not a close dupe.
COSRX The Niacinamide 15 Serum: common questions
Is COSRX The Niacinamide 15 Serum worth it?
COSRX The Niacinamide 15 Serum scores 3.9 out of 5.0 for efficacy (Effective) and 4.4 out of 5.0 for safety (Gentle) on DemythSkin's independent ingredient analysis. A genuinely potent brightening and oil-control serum, but 15% niacinamide is aggressive overkill for many skins—not a universally gentle daily essential.
What are the key active ingredients in COSRX The Niacinamide 15 Serum?
COSRX The Niacinamide 15 Serum contains no gold-standard actives. Its formula is built on supporting and base ingredients rather than clinically transformative actives.
Does COSRX The Niacinamide 15 Serum contain fragrance or known irritants?
DemythSkin's analysis found no flagged irritants in COSRX The Niacinamide 15 Serum. It scores 4.4 out of 5.0 for safety.
How is COSRX The Niacinamide 15 Serum scored?
DemythSkin grades every product on two independent scores: efficacy (whether the ingredients have clinical evidence of working) and safety (irritation and sensitisation risk). Ingredients are graded S through D against a database of over 3,000 compounds. Brand and price are not part of the score, and no brand pays for one.
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