All scans / Serums / COSRX Advanced The Vitamin C 23 Serum
COSRX Advanced The Vitamin C 23 Serum ingredients: is it worth it?
This is a clinically serious brightening/antioxidant serum with an aggressive but well-supported vitamin C system that will work beautifully on resilient skin and absolutely terrorize an unprepared barrier.
This is a clinically serious brightening/antioxidant serum with an aggressive but well-supported vitamin C system that will work beautifully on resilient skin and absolutely terrorize an unprepared barrier.
READ MORE
Efficacy is high because you get both pure ascorbic acid and S Tier 3‑O‑ethyl ascorbic acid, reinforced by niacinamide, licorice, glutathione, tocotrienol and multiple antioxidants, but the very high acid load and potential low pH mean that users with sensitive or compromised skin will trade results for stinging, dryness and barrier stress unless they buffer with a robust moisturizer and introduce it slowly.
We may earn a commission from qualifying purchases. Links never influence scores.
DemythSkin rates COSRX Advanced The Vitamin C 23 Serum 4.6/5 for efficacy and 4.2/5 for safety.
ACTIVE INGREDIENTS BY TIER
Gold Standards
High clinical proof | Skin-transformativeReliable
Proven resultsPotent
Developing evidenceOverhyped | Marketing
Hype | Limited dataDocumented Irritants
Evidence-backed flagFULL INGREDIENT LIST⌄
3-O-Ethyl Ascorbic Acid Acetyl Glucosamine Adenosine Allantoin Aqua/water Arginine Ascorbic Acid BETA-CAROTENE Butylene Glycol Caffeine Carthamus Tinctorius (Safflower) Seed Oil Dimethicone Disodium EDTA Elaeis Guineensis (Palm) Oil Ethylhexylglycerin Glycyrrhiza Glabra (Licorice) Root Extract Helianthus Annuus (Sunflower) Seed Oil Hydrogenated Lecithin Methyl Glucose Sesquistearate Methyl Trimethicone Niacinamide Panthenol Polyglyceryl-3 Methylglucose Distearate Potassium Cetyl Phosphate Propanediol Squalane Sodium Chloride Sodium Hyaluronate Sodium Sulfite Tocopherol Tocotrienol Carbomer Centella Asiatica Extract Daucus Carota Sativa (Carrot) Root Extract Glutathione Tromethamine
WHAT EACH INGREDIENT DOES (24)⌄
- 3-O-Ethyl Ascorbic Acid
- Stable vitamin C brightening antioxidant
- Acetyl Glucosamine
- Supports exfoliation and brightening
- Adenosine
- Anti-aging, improves wrinkles
- Allantoin
- Soothing, reduces irritation
- Aqua / Water
- Solvent base for the formula
- Arginine
- pH adjuster and skin-conditioning
- Ascorbic Acid
- Pure vitamin C antioxidant, brightening
- Beta-Carotene
- Pro-vitamin A antioxidant pigment
- Butylene Glycol
- Humectant and solvent
- Caffeine
- Antioxidant, may reduce puffiness
- Carthamus Tinctorius (Safflower) Seed Oil
- Emollient, linoleic-rich plant oil
- Dimethicone
- Silicone emollient, slip and barrier support
- Disodium EDTA
- Chelating agent, stabilizes formula
- Elaeis Guineensis (Palm) Oil
- Emollient, occlusive plant oil
- Ethylhexylglycerin
- Preservative booster, humectant
- Glycyrrhiza Glabra (Licorice) Root Extract
- Brightening, anti-inflammatory
- Helianthus Annuus (Sunflower) Seed Oil
- Emollient, barrier support
- Hydrogenated Lecithin
- Emulsifier, helps delivery of actives
- Methyl Glucose Sesquistearate
- Emulsifier and texture enhancer
- Methyl Trimethicone
- Volatile silicone for light texture
- Niacinamide
- Multifunction brightening and barrier support
- Panthenol
- Humectant and soothing provitamin B5
- Polyglyceryl-3 Methylglucose Distearate
- Emulsifier, helps stabilize emulsion
- Potassium Cetyl Phosphate
- Anionic emulsifier, stabilizes oil phase
EXTERNAL CITATIONS
Ascorbic Acid: High-concentration L-ascorbic acid (10–20% range) has robust evidence for reducing hyperpigmentation and improving photoaging when formulated at pH ~3, as shown in multiple clinical studies.
3-O-Ethyl Ascorbic Acid: Ethylated vitamin C derivatives demonstrate melanin inhibition and collagen promotion with better stability than L-ascorbic acid in in vitro and small clinical studies.
Niacinamide: Topical niacinamide at 4–5% reduces hyperpigmentation and improves fine lines and barrier function in randomized controlled trials.
Licorice Root Extract: Glabridin-containing licorice extracts inhibit UV-induced pigmentation and have documented skin-brightening and anti-inflammatory effects.
Glutathione: Glutathione has melanin-modulating and antioxidant effects; topical evidence is emerging but less robust than oral/IV use, with small studies suggesting modest brightening.
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 (31%), not a close dupe.
COSRX Advanced The Vitamin C 23 Serum: common questions
Is COSRX Advanced The Vitamin C 23 Serum worth it?
COSRX Advanced The Vitamin C 23 Serum scores 4.6 out of 5.0 for efficacy (Gold Standard) and 4.2 out of 5.0 for safety (Gentle) on DemythSkin's independent ingredient analysis. This is a clinically serious brightening/antioxidant serum with an aggressive but well-supported vitamin C system that will work beautifully on resilient skin and absolutely terrorize an unprepared barrier.
What are the key active ingredients in COSRX Advanced The Vitamin C 23 Serum?
COSRX Advanced The Vitamin C 23 Serum contains these gold-standard actives with strong clinical evidence: Ascorbic Acid.
Does COSRX Advanced The Vitamin C 23 Serum contain fragrance or known irritants?
DemythSkin flags these ingredients in COSRX Advanced The Vitamin C 23 Serum as documented irritants: Ethylhexylglycerin.
How is COSRX Advanced The Vitamin C 23 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.
Free scores for every product in the database, or see them on Sephora, Ulta and Amazon with the Chrome extension.