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    COSRX

    COSRX Advanced The Vitamin C 23 Serum

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    A 23% pure vitamin C serum that fades dark spots and brightens uneven tone.

    Our Asian beauty edit
    €22.5020ml · €112.50/100 ml · incl. VAT
    1

    In stock · dispatched in 1–2 working days

    In your routine

    CleanseToneTreatMoisturiseProtect
    Step
    5 · Treat
    How often
    Up to 2 times a week
    Starting out
    Every second morning for one week, then every morning under SPF. A mild tingle for a minute is normal; stinging that lasts is not, so drop to every third day.

    • Ascorbic Acid (23%)High-strength pure vitamin C that brightens skin and targets dark spots, but carries higher irritation potential than derivative forms.
    • 3-O-Ethyl Ascorbic AcidA more stable, gentler vitamin C derivative that supports brightening alongside the pure acid.
    • GlutathioneAntioxidant that supports skin's defence against environmental stress and works synergistically with vitamin C.
    • Sodium HyaluronateHumectant that helps offset the potential dryness of a high-strength acid formula.

    After cleansing and toning, apply a small amount evenly to face, avoiding the eye area; introduce gradually (2-3x per week) before building to daily use, and always follow with SPF the next morning. Best used in the PM given its high acid strength.

    Aqua/Water, Ascorbic Acid(23%), Butylene Glycol, Dimethicone, Panthenol, 3-O-Ethyl Ascorbic Acid, Squalane, Sodium Hydroxide, Caffeine, Sodium Hyaluronate, Sodium Metaphosphate, Adenosine, Acetyl Glucosamine, Gardenia Florida Fruit Extract, Allantoin, Dextrin, Tocotrienols, Tocopherol, Elaeis Guineensis (Palm) Oil, Arginine, Niacinamide, Pentylene Glycol, Glutathione, Helianthus Annuus (Sunflower) Seed Oil, Methyl Trimethicone, Carthamus Tinctorius (Safflower) Seed Oil, Camellia Japonica Seed Oil, Daucus Carota Sativa (Carrot) Root Extract, Glycyrrhiza Glabra (Licorice) Root Extract, Beta-Carotene

    A high-potency serum built on 23% pure ascorbic acid plus 3-O-ethyl ascorbic acid, formulated to visibly fade dark spots, refine texture, and boost radiance. This is a fast-absorbing, professional-strength formula — because of its high concentration, it's best introduced gradually and is not recommended for first-time vitamin C users or highly reactive skin.

    Key Benefits:

    • High-strength 23% ascorbic acid targets dark spots and uneven tone
    • Refines the look of texture and dullness
    • Fast-absorbing, lightweight serum texture
    • Antioxidant support from vitamin E and glutathione
    • Best for vitamin-C-experienced users seeking visible brightening results

    Suitable for

    • acne-prone
    • Fragrance-free
    • do not combine with benzoyl peroxide
    • not on broken skin
    • not around eyes

    Highlights

    Pigmentation
    Radiance
    Hyaluronic Acid
    Vitamin C
    Fragrance-free

    Questions

    It's one of the strongest pure-ascorbic-acid serums you can buy, so build up slowly: start two to three evenings a week and increase as your skin adapts. If you're new to vitamin C or have sensitive skin, a gentler derivative formula is a better first step — ask us.

    Its 23% pure ascorbic acid with glutathione targets dark spots, post-blemish marks and dull, uneven tone. With consistent use most people see brighter skin in three to four weeks and meaningful fading of pigmentation over eight to twelve weeks. Always wear SPF alongside it.

    This one is best at night due to its high strength — apply a small amount to clean, dry skin, avoiding the eye area, and follow with SPF the next morning. Store it cool and dark and use it within a few months of opening, as pure vitamin C oxidises.

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