
Highlights
WHAT IS IT?
Vitamin C serum
FEATURES
23% pure vitamin C, improves skin tone, reduces wrinkles, targets dull and rough skin
BEST FOR
Sensitive skin
CHECKS
Free of sulfates, parabens
Who Is It For?
What Does It Help With?
Skin Elasticity Skin Tone Wrinkles Dull And Rough SkinBudget
Mid-rangeHow To Use
Which routine should it be used in?
Instructions:
Key Information
What COSRX Official Says
Product Description:
Enhances skin elasticity with 23% pure vitamin C. The 23% highly concentrated stabilized pure vitamin C serum improves skin tone, reduces wrinkles, and targets dull and rough skin as a vitamin C booster. This serum is highly effective, and to slowly prevent oxidation, it is divided into two layers with oil on top of the serum, providing a moisturizing finish.
About the Brand:
Ingredients Overview
Ingredients List
Water, Ascorbic Acid(23%), Propanediol, Dimethicone, Tromethamine, Panthenol, Ethyl Ascorbyl Ether, Squalane, Caffeine, Sodium Chloride, Sodium Hyaluronate, Sodium Sulfite, Disodium EDTA, Glutathione, Adenosine, Acetyl Glucosamine, Gardenia Florida Fruit Extract, Allantoin, Dextrin, Tocotrienols, Tocopherol, Elaeis Guineensis (Palm) Oil, Butylene Glycol, Arginine, Niacinamide, Pentylene Glycol, Alcohol Denat., Helianthus Annuus (Sunflower) Seed Oil, Glycyrrhiza Glabra (Licorice) Root Extract, Methyl Trimethicone, Carthamus Tinctorius (Safflower) Seed Oil, Camellia Japonica Seed Oil, Daucus Carota Sativa (Carrot) Root Extract, Beta-Carotene
Key Ingredients
23% Pure Vitamin C (Ascorbic acid), Super vitamin E (Tocotrienol), Hyaluronic acid, Allantoin
Ingredients Details
Caffeine
Common Name(s): Caffeine,methylxanthine anti-cellulite,antioxidant vasoactive
CAS Number: N/a
DESCRIPTION
What It Does: Stimulates lipolysis in adipocytes by inhibiting phosphodiesterase (preventing camp breakdown), reduces eye puffiness through vasoconstriction of periorbital capillaries, and provides antioxidant dna repair stimulation for photoprotective benefit.
Why It's Used: The only cosmetic active with a well-defined mechanism for anti-cellulite claims โ phosphodiesterase inhibition elevating adipocyte camp is the documented biochemical pathway, providing mechanism-based efficacy substantiation superior to most slimming actives.
How It Works: Caffeine inhibits phosphodiesterase (pde3, pde4) preventing camp hydrolysis โ elevated camp activates protein kinase a โ phosphorylates hormone-sensitive lipase โ lipolysis of triglycerides in adipocytes. for eye puffiness: caffeine's adenosine receptor antagonism reduces prostaglandin-mediated capillary dilation in periorbital tissue, reducing fluid accumulation.
Typically Found In: Anti-cellulite,eye creams,antioxidant products
TECHNICAL DETAILS
Primary Category: Active ingredient โ antioxidant
Secondary Functions: Free radical scavenging,anti-aging
Application Areas:
Facial Skincare
Body Care
Hair Care
Beard Care
Color Cosmetics (Makeup)
Dietary/Oral Supplements
Typical Concentration Range: 0.1%โ3%
SOURCING & ETHICS
Vegan Status: Yes
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: Non-irritating; well-tolerated.
Safe for Sensitive Skin: Yes
SAFETY & COMPATIBILITY
Safety Profile: Excellent safety profile. ewg score: 1.
Works Well With: Vitamin c,vitamin e,ferulic acid,spf,other antioxidants
Avoid Combining With: No significant incompatibilities
SCIENTIFIC NOTE
Caffeine has one of the highest sc penetration rates of any cosmetic active (logp -0.07, mw 194 da) โ the combination of small size and moderate logp providing excellent aqueous solubility with sufficient sc lipid partitioning for effective transdermal delivery to adipose tissue.
Last Verified: Cosing database,caffeine pde inhibitor anti-cellulite lipolysis review
Primary Sources: 2026-03-12
Dimethicone
Common Name(s): Pdms,polydimethylsiloxane,silicone fluid
CAS Number: 9006-65-9
DESCRIPTION
What It Does: Provides silicone-characteristic silky feel and skin protection with adjustable viscosity.
Why It's Used: The benchmark cosmetic silicone โ sets the gold standard for silky application feel, spreadability, and skin protection in virtually all skin care categories.
How It Works: Polydimethylsiloxane chain flexibility provides extremely low surface tension and high spreadability. inert si-o backbone provides chemical stability and excellent skin tolerance. occlusive film formation reduces tewl. higher viscosity grades provide more intense conditioning.
Typically Found In: Moisturizers,foundations,primers,sunscreens โ nearly universal
TECHNICAL DETAILS
Primary Category: Functional ingredient โ polydimethylsiloxane
Secondary Functions: Barrier sealing,softening
Application Areas:
Facial Skincare
Body Care
Hair Care
Beard Care
Color Cosmetics (Makeup)
Dietary/Oral Supplements
Typical Concentration Range: 0.1%โ30%
SOURCING & ETHICS
Vegan Status: Yes โ synthetic
Halal Status: Yes
Source Notes: Plant-derived, synthetic or animal-derived. verify source.
SKIN COMPATIBILITY
Irritancy Rating: 1/5 โ very low
Comedogenicity Rating: 1/5 โ low; formulation-dependent
Sensitivity Concerns: Non-irritating.
Safe for Sensitive Skin: Yes
SAFETY & COMPATIBILITY
Safety Profile: Excellent safety profile. ewg score: 1.
Works Well With: Humectants,ceramides,actives as carrier
Avoid Combining With: No significant incompatibilities
SCIENTIFIC NOTE
Dimethicone's exceptional silky feel arises from its very low intermolecular attractive forces (weak van der waals forces due to non-polar methyl groups) that allow silicone chains to slide freely over skin. the coefficient of kinetic friction for pdms against skin (~0.04) is among the lowest of any cosmetic material โ explaining why even small amounts transform product feel.
Last Verified: Cosing database,cir safety assessment
Primary Sources: 2026-03-12
Panthenol
Common Name(s): Provitamin b5,d-panthenol,dl-panthenol,d-pantothenyl alcohol,(r)-2,4-dihydroxy-n-(3-hydroxypropyl)-3,3-dimethylbutanamide
DESCRIPTION
What It Does: Panthenol deeply moisturizes skin and hair, soothes irritation, accelerates wound healing, strengthens the skin barrier, and improves hair elasticity and shine.
Why It's Used: It is used because it is exceptionally versatile, working in both skin and hair formulations. it is gentle enough for sensitive and post-procedure skin, and converts to the active vitamin b5 within the skin.
How It Works: Panthenol penetrates skin and hair, where it is oxidized to pantothenic acid (vitamin b5), a coenzyme a precursor essential to metabolism. in skin, it acts as a humectant and stimulates fibroblast proliferation. in hair, it coats the shaft, improving manageability.
Typically Found In: Moisturizers,serums,toners,after-sun products,wound healing products,shampoos,conditioners,hair masks,beard care
TECHNICAL DETAILS
Primary Category: Active ingredient โ provitamin b5
Secondary Functions: Anti-inflammatory,wound healing,hair conditioning
Application Areas:
Facial Skincare
Body Care
Hair Care
Beard Care
Color Cosmetics (Makeup)
Dietary/Oral Supplements
Typical Concentration Range: 0.5%โ5% (typical: 1โ3%)
SOURCING & ETHICS
Vegan Status: Yes โ synthetically produced
Halal Status: Yes
Source Notes: Commercially synthesized. both d- and dl-forms used in cosmetics; d-panthenol is the biologically active isomer but dl-panthenol is less expensive and widely used.
SKIN COMPATIBILITY
Irritancy Rating: 1/5 โ very low; one of the most soothing ingredients in cosmetics
Comedogenicity Rating: 0/5 โ non-comedogenic
Sensitivity Concerns: Extremely rare contact allergy; considered one of the safest cosmetic ingredients. suitable for all skin types.
Safe for Sensitive Skin: Yes โ ideal for sensitive, reactive, and post-procedure skin
SAFETY & COMPATIBILITY
Safety Profile: Exceptionally safe. ewg hazard score: 1. no significant concerns for irritation, sensitization, or systemic toxicity. safe during pregnancy.
Works Well With: Hyaluronic acid,ceramides,allantoin,niacinamide,centella asiatica,retinol (reduces irritation),glycerin
Avoid Combining With: No known significant incompatibilities
SCIENTIFIC NOTE
Panthenol has demonstrated wound-healing properties in clinical studies, stimulating fibroblast proliferation and migration. its dual humectant and anti-inflammatory action makes it particularly effective in barrier-repair formulations.
Last Verified: Cosing database,cir safety assessment,ebner et al. (2002) skin pharmacology and applied skin physiology
Primary Sources: 2026-03-12
Propanediol
Common Name(s): 1,3-propanediol,zemea,bio-propanediol
CAS Number: 504-63-2
DESCRIPTION
What It Does: Provides humectant and solvent functionality from sustainable corn-based fermentation.
Why It's Used: Bio-based propylene glycol alternative from renewable corn โ propanediol provides equivalent functionality to propylene glycol with sustainable renewable feedstock and superior skin feel.
How It Works: Two oh groups provide humectant water binding. excellent solvent for fragrances, actives, and preservatives. mild antimicrobial from diol structure for preservative system boosting. renew corn fermentation origin (dupont zemea process). better skin feel than propylene glycol โ less sticky.
Typically Found In: Virtually all cosmetic categories as pg alternative
TECHNICAL DETAILS
Primary Category: Functional ingredient โ humectant
Secondary Functions: Tewl reduction,skin plumping
Application Areas:
Facial Skincare
Body Care
Hair Care
Beard Care
Color Cosmetics (Makeup)
Dietary/Oral Supplements
Typical Concentration Range: 1%โ20%
SOURCING & ETHICS
Vegan Status: Yes โ from corn sugar fermentation
Halal Status: Yes
Source Notes: Synthetic or naturally derived. excellent aqueous solubility.
SKIN COMPATIBILITY
Irritancy Rating: 1/5 โ very low
Comedogenicity Rating: 0/5 โ non-comedogenic
Sensitivity Concerns: Non-irritating; suitable for all skin types.
Safe for Sensitive Skin: Yes
SAFETY & COMPATIBILITY
Safety Profile: Excellent safety profile. ewg score: 1.
Works Well With: Ceramides,emollients,occlusives,glycerin,hyaluronic acid
Avoid Combining With: No significant incompatibilities
SCIENTIFIC NOTE
Propanediol's dupont tate & lyle bio products 'zemea' process ferments corn sugar to 1,3-propanediol using engineered e. coli โ one of the first commercially viable bio-fermentation routes to a cosmetic diol previously made only from petroleum. the renewable route produces chemically identical 1,3-propanediol while reducing carbon footprint by approximately 40% vs petrochemical synthesis.
Last Verified: Cosing database,dupont tate & lyle zemea technical data,cir safety assessment
Primary Sources: 2026-03-12