
Highlights
WHAT IS IT?
Blemish treatment serum
FEATURES
Highly concentrated with 2% AHA and 2% BHA serum in a pure cotton ball, soothes acne-scarred skin, cares for blackheads and whiteheads.
BEST FOR
Acne-prone skin, skin with blackheads and whiteheads
CHECKS
Free of sulfates, parabens
Who Is It For?
Adults (18+) Both Men And WomenWhat Does It Help With?
Acne Scars Blackheads WhiteheadsBudget
AffordableHow To Use
Which routine should it be used in?
Instructions:
Key Information
What COSRX Says
Product Description:
Highly concentrated with 2% AHA and 2% BHA, this serum in a pure cotton ball quickly and easily soothes acne-scarred skin and instantly cares for blackheads and whiteheads.
About the Brand:
Ingredients Overview
Ingredients List
Water, Propanediol, Polysorbate 20, Glycolic Acid, Salicylic Acid, Gluconolactone, Zinc PCA, Allantoin, Sodium Hyaluronate, Sodium Hydroxide, Dipropylene Glycol, Hydroxyacetophenone, Caprylyl Glycol, Ethylhexylglycerin, Dipotassium Glycyrrhizate, 1,2-Hexanediol, Disodium EDTA
Key Ingredients
AHA 2%, BHA 2%
Ingredients Details
Allantoin
Common Name(s): 5-ureidohydantoin,glyoxyldiureide,aluminum dihydroxy allantoinate
CAS Number: 97-59-6
DESCRIPTION
What It Does: Soothes irritation, accelerates wound healing, promotes skin cell renewal, and provides mild keratolytic exfoliation.
Why It's Used: Gold standard multi-function soothing active โ one of the most widely used cosmetic ingredients across all product types for its exceptional tolerability and clinically proven multi-action skin conditioning.
How It Works: Promotes keratinocyte proliferation and fibroblast migration for wound healing. mild keratolytic activity by disrupting corneocyte binding. anti-irritant via direct protein binding and anti-inflammatory cytokine reduction. humectant activity via hydroxyl groups.
Typically Found In: Post-procedure products,sensitive skin formulas,wound care,anti-acne treatments,baby products
TECHNICAL DETAILS
Primary Category: Active ingredient โ soothing / anti-inflammatory
Secondary Functions: Wound healing,keratolytic,anti-irritant
Application Areas:
Facial Skincare
Body Care
Hair Care
Beard Care
Color Cosmetics (Makeup)
Dietary/Oral Supplements
Typical Concentration Range: 0.1%โ2%
SOURCING & ETHICS
Vegan Status: Yes โ synthetic or comfrey-derived
Halal Status: Yes
Source Notes: Plant-derived extract or synthetic.
SKIN COMPATIBILITY
Irritancy Rating: 1/5 โ very low
Comedogenicity Rating: 0/5 โ non-comedogenic
Sensitivity Concerns: Exceptionally well-tolerated; suitable for all skin types including baby and compromised skin.
Safe for Sensitive Skin: Yes โ particularly recommended for sensitive skin
SAFETY & COMPATIBILITY
Safety Profile: Excellent safety profile. ewg score: 1.
Works Well With: Ceramides,panthenol,allantoin,hyaluronic acid,centella asiatica
Avoid Combining With: No significant incompatibilities
SCIENTIFIC NOTE
Allantoin's keratinocyte proliferation stimulation occurs via receptor-mediated signaling (possibly machr activation) rather than non-specific irritation-driven proliferation, making it a true wound-healing stimulant rather than a pro-inflammatory proliferative signal.
Last Verified: Cosing database,cir safety assessment,araรบjo et al. allantoin review
Primary Sources: 2026-03-12
Gluconolactone
Common Name(s): D-gluconolactone,delta-gluconolactone
CAS Number: 90-80-2
DESCRIPTION
What It Does: Provides the gentlest chemical exfoliation with simultaneous antioxidant, moisture retention, and barrier support.
Why It's Used: Preferred exfoliant for rosacea, eczema, sensitive skin, and post-procedure recovery where standard ahas cause unacceptable irritation.
How It Works: Hydrolyzes slowly on skin surface to gluconic acid providing gentle exfoliation. multiple hydroxyl groups enable water binding (humectant) and metal chelation (antioxidant).
Typically Found In: Sensitive skin exfoliants,rosacea treatments,eczema care,post-procedure recovery
TECHNICAL DETAILS
Primary Category: Active ingredient โ polyhydroxy acid (pha)
Secondary Functions: Gentle exfoliation,antioxidant,humectant
Application Areas:
Facial Skincare
Body Care
Hair Care
Beard Care
Color Cosmetics (Makeup)
Dietary/Oral Supplements
Typical Concentration Range: 5%โ15%
SOURCING & ETHICS
Vegan Status: Yes โ fermentation or synthetic
Halal Status: Yes
Source Notes: Fermentation-derived from glucose or synthetic. among the safest chemical exfoliants available.
SKIN COMPATIBILITY
Irritancy Rating: 1/5 โ very low
Comedogenicity Rating: 0/5 โ non-comedogenic
Sensitivity Concerns: No photosensitization; no stinging; suitable for very sensitive skin.
Safe for Sensitive Skin: Yes โ ideal for sensitive, reactive, rosacea, and eczema-prone skin; no photosensitization
SAFETY & COMPATIBILITY
Safety Profile: Exceptional safety profile. no photosensitization. ewg score: 1.
Works Well With: Ceramides,niacinamide,hyaluronic acid,soothing actives
Avoid Combining With: No significant incompatibilities
SCIENTIFIC NOTE
Phas have molecular weights 2โ3ร larger than ahas, limiting penetration to superficial layers. combined humectant and antioxidant properties make them uniquely well-tolerated while providing meaningful exfoliation.
Last Verified: Cosing database,green & yu (2003) pha review,cir safety assessment
Primary Sources: 2026-03-12
Glycolic Acid
Common Name(s): Hydroxyacetic acid,2-hydroxyacetic acid
CAS Number: 79-14-1
DESCRIPTION
What It Does: Provides maximum aha efficacy from the smallest most penetrating alpha-hydroxy acid.
Why It's Used: The most potent aha โ glycolic acid's smallest molecular size provides the deepest penetration and highest efficacy of any alpha-hydroxy acid for exfoliation and anti-aging.
How It Works: Smallest aha (mw 76) provides deepest stratum corneum penetration. disrupts corneodesmosomes reducing cohesion. stimulates fibroblast collagen i and iii synthesis. efficacy is ph-dependent โ free acid fraction determines activity.
Typically Found In: Chemical peels,body lotions,anti-aging serums,exfoliating toners
TECHNICAL DETAILS
Primary Category: Active ingredient โ primary aha
Secondary Functions: Brightening,collagen stimulation
Application Areas:
Facial Skincare
Body Care
Hair Care
Beard Care
Color Cosmetics (Makeup)
Dietary/Oral Supplements
Typical Concentration Range: 1%โ10% cosmetic; higher professional
SOURCING & ETHICS
Vegan Status: Yes โ synthetic or fermentation-derived
Halal Status: Yes
Source Notes: Fermentation-derived or synthetic. ph must be โค4.0 for aha activity.
SKIN COMPATIBILITY
Irritancy Rating: 2/5 โ low to moderate
Comedogenicity Rating: 0/5 โ non-comedogenic
Sensitivity Concerns: Photosensitizing โ mandatory spf use. start at low frequency.
Safe for Sensitive Skin: Use with caution โ spf required
SAFETY & COMPATIBILITY
Safety Profile: Eu cosmetics: max 10% leave-on, ph โฅ3.5, mandatory sun protection advisory. professional peel concentrations regulated separately.
Works Well With: Niacinamide,ceramides,hyaluronic acid,spf
Avoid Combining With: Retinol in same step; multiple exfoliants simultaneously
SCIENTIFIC NOTE
Glycolic acid's ph-dependent efficacy is critical: at ph 3.0 ~100% is in the free acid (membrane-permeable) form; at ph 3.5 ~70%; at ph 4.0 ~50%. the eu ph โฅ3.5 requirement reduces free acid proportion, lowering efficacy but also reducing irritation โ why professional peel concentrations at lower ph are far more active than equivalent cosmetic concentrations.
Last Verified: Cosing database,eu aha guidelines,cir safety assessment
Primary Sources: 2026-03-12
Polysorbate 20
Common Name(s): Tween 20,poe(20) sorbitan monolaurate
CAS Number: 9005-64-5
DESCRIPTION
What It Does: Solubilizes fragrance oils and other lipophilic ingredients into water-based formulations.
Why It's Used: Standard fragrance solubilizer for water-based formulations โ the industry standard for incorporating oil-soluble fragrances and actives into aqueous systems without separate oil phase.
How It Works: Hlb ~16.7 provides strong solubilization capacity for oils in water. laurate (c12) chain provides milder skin interaction than higher-hlb polysorbates. polyoxyethylene chains (20 eo units) provide high water solubility. effective solubilizer at 3-4:1 polysorbate:fragrance ratio.
Typically Found In: Toners,micellar waters,fragrance-containing aqueous products
TECHNICAL DETAILS
Primary Category: Functional ingredient โ sorbitan ester emulsifier/solubilizer
Secondary Functions: Skin conditioning
Application Areas:
Facial Skincare
Body Care
Hair Care
Beard Care
Color Cosmetics (Makeup)
Dietary/Oral Supplements
Typical Concentration Range: 0.5%โ5%
SOURCING & ETHICS
Vegan Status: Conditional โ sorbitol from plant, peg from petroleum
Halal Status: Yes
Source Notes: Commercially produced for cosmetic use. verify vegan/halal status with supplier.
SKIN COMPATIBILITY
Irritancy Rating: 1/5 โ very low
Comedogenicity Rating: 0/5 โ non-comedogenic
Sensitivity Concerns: Well-tolerated by most skin types.
Safe for Sensitive Skin: Yes
SAFETY & COMPATIBILITY
Safety Profile: Same peg 1,4-dioxane concern as all peg compounds. quality-grade ps-20 should be tested for impurities.
Works Well With: Standard skincare actives
Avoid Combining With: No known significant incompatibilities
SCIENTIFIC NOTE
Polysorbate 20's optimal solubilization ratio (3-4 parts ps-20 per part fragrance oil) is lower than expected from pure hlb theory. this efficiency arises from polysorbate's formation of very small, stable oil-in-water microemulsions (droplets <50nm) rather than conventional emulsions, providing optically clear, thermodynamically stable fragrance incorporation that conventional emulsifiers cannot achieve.
Last Verified: Cosing database,cir safety assessment
Primary Sources: 2026-03-12