What it is:

COSRX The Vitamin C 23 Serum is a high-potency Korean vitamin C serum designed to visibly brighten dull skin, improve the look of uneven tone, and support a clearer, more radiant complexion. Formulated for those who want a concentrated antioxidant treatment, this lightweight serum helps target the appearance of post-blemish marks, tired-looking skin, and early signs of aging while adding a fresh, healthy glow. Despite its treatment-focused profile, it also includes moisturizing and soothing components that help the skin feel more balanced and comfortable. Ideal for a results-driven skincare routine, this serum is a strong choice for anyone looking to add a powerful brightening step to their daily regimen.

Who it’s for

This serum is best suited to those concerned with dullness, uneven skin tone, lack of radiance, and visible signs of fatigue. It is especially appealing to shoppers looking for a potent Korean vitamin C serum that helps improve the appearance of discoloration and supports smoother, more luminous skin over time. Because it is a concentrated formula, it is particularly well suited to users who already have some experience with active skincare or who want a more intensive brightening treatment in their routine.

Why it’s special

What makes this serum special is its strong brightening performance paired with a more refined, skincare-first feel. It helps the complexion look fresher, clearer, and more energized while supporting a smoother, healthier-looking finish. The formula is designed for visible radiance and tone correction, making it especially valuable for skin that looks tired or uneven. It feels like a premium treatment step for those who want their Korean skincare routine to deliver both glow and clarity with a more advanced approach.

Ingredients that make the difference 

Ascorbic Acid
A powerful form of vitamin C that helps visibly brighten dull skin, improve the look of uneven tone, and deliver antioxidant support for a more radiant complexion.

Ethyl Ascorbyl Ether
A vitamin C derivative that helps support brightness and clarity while complementing the formula’s overall antioxidant benefits.

Glutathione
An antioxidant ingredient that helps promote a fresher, more luminous appearance and supports a more even-looking skin tone.

Who can use it?

COSRX The Vitamin C 23 Serum is suitable for those looking for a high-strength brightening serum, especially for normal, combination, and oily skin types, as well as anyone focused on dullness and visible discoloration. Dry skin can also use it when paired with hydrating and barrier-supportive products. Because this is a potent vitamin C formula, very sensitive skin or first-time active users may prefer to introduce it gradually and patch test first. Daily sunscreen is essential when using brightening treatments.