COSRX The Vitamin C 23 Serum

COSRX The Vitamin C 23 Serum is a high-strength brightening serum with 23% pure vitamin C designed to improve the appearance of dullness, uneven skin tone, dark spots and early signs of aging.

The dual-layer formula combines 23% ascorbic acid with 3-O-ethyl ascorbic acid, panthenol, squalane, caffeine, sodium hyaluronate, niacinamide, glutathione, tocopherol and tocotrienols. It helps support a brighter, more even-looking complexion while providing additional hydration and antioxidant care. COSRX recommends this concentration especially for experienced vitamin C users.

Benefits

• Helps improve the appearance of dark spots and uneven skin tone.
• Helps brighten dull and tired-looking skin.
• Provides antioxidant care against environmental stress.
• Helps support smoother and firmer-looking skin.
• Provides additional moisturizing and soothing care.

Who is it for

• Dull and uneven-looking skin.
• Skin with visible dark spots and post-blemish marks.
• Skin with early signs of aging.
• Skin in need of intensive brightening care.
• Experienced vitamin C users.

Main ingredients

• Ascorbic Acid 23% – pure vitamin C that helps improve the appearance of discoloration, dullness and uneven tone.
• 3-O-Ethyl Ascorbic Acid – a vitamin C derivative that provides additional brightening and antioxidant care.
• Panthenol – helps moisturize and maintain skin comfort.
• Squalane – helps soften the skin and support the moisture barrier.
• Caffeine – provides antioxidant and skin-conditioning care.
• Niacinamide – helps support a brighter and more even-looking complexion.
• Glutathione – provides antioxidant care and supports skin radiance.
• Tocopherol & Tocotrienols – vitamin E antioxidants that help condition and protect the skin.
• Sodium Hyaluronate – helps attract and retain moisture.

How to use

After cleansing and toning, apply 2–3 drops of COSRX The Vitamin C 23 Serum evenly to the face and gently pat until absorbed. Follow with moisturizer. When used during the daytime, apply sunscreen afterward. Before use, close the dropper securely and gently shake the bottle from side to side.

FAQ

How much vitamin C does COSRX The Vitamin C 23 Serum contain?
The formula contains 23% pure ascorbic acid.

Can COSRX The Vitamin C 23 Serum be used every day?
Yes. It can be used in a regular skincare routine, although its high vitamin C concentration makes it better suited to users already accustomed to potent vitamin C products.

How should COSRX The Vitamin C 23 Serum be stored?
Store the opened serum upright in the refrigerator at 3–10°C. COSRX recommends using it within 2 months after opening because pure vitamin C oxidizes easily.

Warnings

• Keep refrigerated at 3–10°C after opening.
• Store upright and keep away from high temperatures and direct sunlight.
• Do not shake vigorously before opening; after attaching the dropper, shake lightly from side to side.
• Use within approximately 2 months after opening.
• When used during the day, follow with sunscreen.
• Avoid using in the same routine with high-concentration copper peptide products or retinol; use them at different times of day instead.