++++
[ DemythSkin Verdict ]
COSRX Refresh AHA BHA Vitamin C Booster Serum
SerumBrightening
Efficacy
Strong
4.3 / 5.0
Safety
Mostly Safe
4.1 / 5.0
System Verdict
Smartly-formulated but mild exfoliating brightening serum that overpromises on “Vitamin C booster” and adds unnecessary fragrance and menthol for sensitive skin. The efficacy sits in the AHA/BHA + niacinamide/alpha-arbutin stack (A/B Tier actives) at useful positions, but the vitamin C derivative is buried mid-late INCI and likely at low percentage, making it more of a supporting antioxidant than a true S Tier vitamin C treatment; pH is acid-adjusted with sodium hydroxide for tolerable daily use, so overall exfoliation/brightening is moderate rather than clinical-strength, which is why the efficacy score lands in the mid–high 3s instead of 4.5+.
Active Ingredients Detected
S Tier: Gold StandardsHigh Clinical Proof | Skin-Transformative
Glycolic Acid
A Tier: Good BasicsProven Results
WaterNiacinamideBetaineWaterPanthenolAllantoinGlycerinSodium HyaluronateAdenosineAscorbyl GlucosideBetaine SalicylateAlpha-Arbutin
B Tier: Supporting IngredientsPromising Ingredients
Butylene Glycol1,2-HexanediolSodium HydroxideHydroxyethylcellulosePolyglyceryl-10 MyristatePolyglyceryl-10 LaurateMenthyl Lactate
C Tier: Marketing IdolsHype | Limited or Weak Data
Mentha Haplocalix Extract
D Tier: Potential IrritantsBe Cautious
Citrus Aurantium Bergamia (Bergamot) Fruit Oil
Analyze on DemythSkin →
DemythSkin is an independent ingredient analyzer. Scores are computed by a deterministic rubric from published clinical evidence — no brand pays for a score.