COSRX The Vitamin C 13 Serum

COSRX The Vitamin C 13 Serum is a lightweight water-based vitamin C serum with 13% pure ascorbic acid that helps improve the appearance of dark spots, uneven tone, dullness and early signs of aging while providing additional hydration.

The formula combines 13% pure vitamin C with 3-O-ethyl ascorbic acid, tocotrienols, hyaluronic acid, allantoin, panthenol, glutathione, niacinamide and licorice root extract. The watery texture absorbs quickly without a heavy or sticky finish and is designed for daily use in both morning and evening skincare routines. Regular use helps support a brighter, smoother and more radiant-looking complexion.

Benefits

• Helps improve the appearance of dark spots and uneven pigmentation.
• Helps brighten dull-looking skin.
• Helps improve skin texture and the appearance of pores.
• Provides antioxidant care against environmental stress.
• Helps support smoother and more elastic-looking skin.
• Provides lightweight hydration.

Who is it for

• Skin with visible dark spots or uneven tone.
• Dull and tired-looking skin.
• Skin with rough or uneven texture.
• Skin showing early signs of aging.
• Those looking for a daily pure vitamin C serum.

Main ingredients

• Pure Vitamin C (Ascorbic Acid) 13% – helps improve the appearance of discoloration and uneven skin tone.
• 3-O-Ethyl Ascorbic Acid – a vitamin C derivative that provides additional antioxidant and brightening care.
• Tocotrienols & Tocopherol – vitamin E antioxidants that help protect against oxidative stress.
• Sodium Hyaluronate – helps attract and retain moisture in the skin.
• Allantoin – helps soothe and maintain skin comfort.
• Panthenol – helps moisturize and support the skin barrier.
• Glutathione – provides antioxidant care and supports a brighter-looking complexion.
• Niacinamide – helps support the skin barrier and improve uneven-looking tone.
• Licorice Root Extract – helps soothe and support a clearer-looking complexion.

How to use

After cleansing, apply a few drops of COSRX The Vitamin C 13 Serum to the face during the serum step. Gently massage from the center of the face outward until fully absorbed. The serum can be used in the morning and evening. When used in the morning, always follow with sunscreen of SPF 30 or higher.

FAQ

Can COSRX The Vitamin C 13 Serum be used every day?
Yes. COSRX designed the 13% formula as a daily vitamin C serum suitable for regular morning and evening use.

Does COSRX The Vitamin C 13 Serum need to be refrigerated?
Yes. COSRX recommends storing the opened serum upright in the refrigerator at 3–10°C to help preserve the active vitamin C.

How long should COSRX The Vitamin C 13 Serum be used after opening?
COSRX recommends using the serum within approximately two months after opening for best freshness and performance.

Warnings

• For external use only.
• When used in the morning, follow with sunscreen of SPF 30 or higher.
• Avoid using at the same time as high-concentration copper peptide products; use them at different times of day instead.
• Discontinue use if irritation, redness, swelling or itching occurs.
• Store upright in the refrigerator at 3–10°C after opening.
• Use within approximately 2 months after opening.
• Keep the container tightly closed and protect it from heat and direct sunlight.