The COSRX The Vitamin C 23 Serum is a high-potency brightening serum formulated with 23% pure ascorbic acid (L-Vitamin C) — one of the highest vitamin C concentrations available in a consumer serum — to visibly brighten dull skin, fade dark spots and deliver powerful antioxidant protection against environmental damage.

Pure ascorbic acid is the most potent and research-backed form of vitamin C in skincare. At 23%, this serum is designed for those who want fast, visible brightening results. The formula includes niacinamide and panthenol to support the skin barrier alongside the high-concentration active.

Key Benefits

• 23% pure vitamin C delivers high-potency brightening and antioxidant protection
• Visibly fades dark spots, hyperpigmentation and post-acne marks
• Protects against UV-related pigmentation and environmental oxidative stress
• Niacinamide and panthenol support barrier health alongside the active
• Improves overall skin radiance and clarity with consistent use

Who It's For

Experienced vitamin C users wanting maximum brightening efficacy. Not recommended for beginners or those with very sensitive skin — start with The Vitamin C 13 Serum if new to vitamin C.

How To Use

After cleansing and toning, apply a small amount to the face and pat gently until absorbed. Use in the morning before SPF. Start every other day and increase to daily as tolerated. Always apply SPF — vitamin C increases photosensitivity.

Pro Tip

Store in a cool, dark place and use within 3 months of opening to maintain potency. If the formula begins to turn yellow or orange, it has oxidised and should be replaced.