COSRX Advanced The Vitamin C 23 Serum

What is this product?

A high-strength brightening serum built on 23% ascorbic acid, supported by a second vitamin C derivative, niacinamide and glutathione, best suited to users already tolerating strong pure vitamin C rather than sensitive skin newcomers.

What makes it different?

Pure ascorbic acid sits second on the list at a printed 23%, which is unusually high, and a second form, 3-O-ethyl ascorbic acid, appears mid-list. The supporting cast covers brightening (niacinamide, glutathione, licorice root extract) and skin-firming (adenosine), with tocopherol and beta-carotene as antioxidants. The formula avoids added fragrance and drying alcohols entirely, but the strength of the acid means irritation risk is a realistic concern. The functional cosmetic notice for wrinkle improvement and brightening is printed on the page.

What is in it?

The full ingredient list as the brand publishes it, in the printed order. Each name links to what we know about that ingredient.

This brand publishes its ingredient list in Korean only. Names below are the matching INCI names from the Korean Cosmetic Association ingredient dictionary.

Key ingredient

• Water
• Ascorbic Acid
• Butylene Glycol
• Dimethicone
• Panthenol
• 3-O-Ethyl Ascorbic Acid
• Squalane
• Sodium Hydroxide
• Caffeine
• Sodium Hyaluronate
• Sodium Metaphosphate
• Adenosine
• Acetyl Glucosamine
• Gardenia Florida Fruit Extract
• Allantoin
• Dextrin
• Tocotrienols
• Tocopherol
• Elaeis Guineensis (Palm) Oil
• Arginine
• Niacinamide
• Pentylene Glycol
• Glutathione
• Helianthus Annuus (Sunflower) Seed Oil
• Methyl Trimethicone
• Carthamus Tinctorius (Safflower) Seed Oil
• Camellia Japonica Seed Oil
• Daucus Carota Sativa (Carrot) Root Extract
• Glycyrrhiza Glabra (Licorice) Root Extract
• Beta-Carotene

Ingredients with no mark are ones we found nothing notable about, and when marks overlap on one ingredient we show the caution first.

We could not place these in the list above: 오일팜오일, 해바라기씨오일, 잇꽃씨오일, 동백나무씨오일

Did the ad claims hold up?

We checked the one line this product advertises against the ingredient list and public documents. None of them hold up. There is nothing behind them.

Claims translated from Korean, originals preserved.

Each line is quoted as the brand published it, and each one was read on its own against the ingredient list and the documents the brand publishes.

How we read these lines