COSRX The Vitamin C 23 Serum 20ml is a high-strength Vitamin C serum formulated with 23% pure Ascorbic Acid to target dullness, uneven skin tone, dark spots and early signs of aging. It combines pure Vitamin C with Super Vitamin E (Tocotrienol), Glutathione, Niacinamide, Hyaluronic Acid and Allantoin for brightening, antioxidant and hydrating care.

The lightweight serum helps skin look brighter, smoother, more even-toned and refreshed. Because it contains a high concentration of pure Vitamin C, it is particularly suited to users who are already familiar with Vitamin C skincare.

Key Benefits

Contains 23% pure Vitamin C
Helps brighten dull and tired-looking skin
Helps improve the appearance of uneven skin tone
Supports dark-spot and post-breakout mark care
Helps improve the look of rough skin texture
Provides antioxidant skincare benefits
Helps skin look smoother and more radiant
Supports firmer, healthier-looking skin
Contains hydrating Hyaluronic Acid
Suitable for all skin types according to COSRX

Key Ingredients

Pure Vitamin C 23% (Ascorbic Acid)
A high-concentration antioxidant ingredient that helps brighten the appearance of skin and improve uneven tone.

Super Vitamin E (Tocotrienol) & Tocopherol
Provides antioxidant support and complements the Vitamin C formula.

Glutathione
Supports brightening and antioxidant skincare.

Niacinamide
Helps improve the appearance of uneven tone and supports a smoother-looking complexion.

Hyaluronic Acid (Sodium Hyaluronate)
Helps attract and retain moisture for hydrated-looking skin.

Allantoin & Panthenol
Help provide soothing and moisturizing care.

Who Should Use It?

Best suited for:

Dull or tired-looking skin
Uneven skin tone
Dark spots and post-breakout marks
Rough or uneven texture
Early signs of aging
Skin lacking radiance
Experienced Vitamin C users looking for a higher-strength formula

Although COSRX lists it as suitable for all skin types, high-strength pure Vitamin C can cause temporary stinging or irritation in some people. Patch testing is recommended, especially for sensitive skin.

How to Use

Cleanse and tone your face.
Apply 2–3 drops of the serum to the entire face.
Gently pat until absorbed.
Follow with moisturizer.
During the daytime, finish with sunscreen.

Because this is a high-concentration Vitamin C serum, introduce it gradually if your skin is sensitive. COSRX recommends avoiding simultaneous use with high-concentration retinol and Copper Peptide products; AHA/BHA may also increase the possibility of irritation.

Storage

Pure Vitamin C is prone to oxidation. COSRX recommends keeping the product refrigerated and away from high temperatures or direct sunlight, and keeping the dropper tightly closed after use.

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