COSRX The Vitamin C 23 Serum - 20ml

Cosrx The Vitamin C 23 Serum is a high-potency brightening serum with 23% pure ascorbic acid (L-ascorbic acid), the maximum effective concentration for advanced vitamin C users. At 23%, this serum delivers powerful brightening, collagen-boosting, and antioxidant benefits that target stubborn dark spots, deep hyperpigmentation, and significant sun damage.

Ethyl ascorbyl ether provides a stable, skin-penetrating vitamin C derivative that extends the serum's efficacy. Tocotrienols (super vitamin E) deliver antioxidant protection 40-60x more potent than regular tocopherols. Glutathione amplifies the brightening cascade. Beta-carotene (provitamin A) adds an additional antioxidant layer. Niacinamide refines pores. Squalane and camellia seed oil moisturise. Panthenol soothes. Adenosine firms.

Why customers love it

• 23% pure ascorbic acid: maximum-strength vitamin C
• Ethyl ascorbyl ether: stable, penetrating vitamin C derivative
• Tocotrienols: super vitamin E, 40-60x more potent
• Glutathione: master antioxidant brightener
• Beta-carotene: provitamin A antioxidant
• Niacinamide: pore-refining and tone-evening
• Squalane + camellia oil: moisturising buffer
• Advanced formula: for experienced vitamin C users

Perfect for: stubborn dark spots, deep hyperpigmentation, significant sun damage, advanced anti-aging, experienced vitamin C users, uneven tone, fine lines, wrinkles.

Ascorbic Acid (23%) , maximum-strength pure L-ascorbic acid

Ethyl Ascorbyl Ether , stable, skin-penetrating vitamin C derivative

Tocotrienols , super vitamin E antioxidant (40-60x more potent than tocopherol)

Glutathione , master antioxidant and skin brightener

Beta-Carotene , provitamin A, additional antioxidant layer

Niacinamide , pore-refining and tone-evening vitamin B3

Sodium Hyaluronate , hydrating humectant

Squalane , lightweight moisture and formula stabiliser

Camellia Japonica Seed Oil , nourishing omega fatty acids

Carthamus Tinctorius (Safflower) Seed Oil , linoleic acid-rich emollient

Daucus Carota Sativa (Carrot) Root Extract , beta-carotene antioxidant source

Panthenol , soothing vitamin B5

Adenosine , anti-wrinkle and firming

1. After cleansing and toning, dispense 3-4 drops onto your fingertips.
2. Gently pat and press across your face, focusing on dark spots and problem areas.
3. Follow with moisturiser.
4. Use in the evening to start, then add morning use once tolerated.
5. Always apply sunscreen in the morning (essential with high-concentration vitamin C).

Pro tip: This is the advanced version of the Vitamin C 13, only upgrade to this if you've used the 13% comfortably for at least a month. At 23%, you may experience a mild tingling sensation when first applied, this is normal and should subside within a minute. If it persists or burns, buffer by applying moisturiser first, then the serum on top. The additional beta-carotene and carrot root extract give this a slightly warmer tone than the 13% version. Store in a cool, dark place, high-concentration ascorbic acid oxidises faster. The safflower and camellia oils provide a moisturising buffer that makes the 23% concentration more tolerable than competing products at the same strength.