Can beginners use a 23% Vitamin C serum?

Yes—start 2–3 times per week and increase as tolerated. Pair with moisturizer and daily sunscreen.

Can I layer it with niacinamide, retinoids, or acids?

It layers with most routines. If using strong actives (retinoids/AHAs/BHAs) and you are sensitive, alternate days or split AM/PM.

How should I store this serum to keep it stable?

Keep the cap tightly closed, away from heat, humidity, and direct light. Use within the recommended period after opening.

Will it sting on application?

Mild tingling can occur with high-strength Vitamin C. If persistent, reduce frequency or apply over slightly damp skin followed by moisturizer.

When will I see results?

Brightening and texture refinement often appear within 2–4 weeks with consistent use; dark spots and fine lines may take longer depending on skin cycle and sun exposure.

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COSRX

COSRX Advanced The Vitamin C 23 Serum 20ml / 0.67 fl oz

Name: COSRX Advanced The Vitamin C 23 Serum 20ml / 0.67 fl oz
Brand: COSRX
Price: 17.43 USD
Availability: InStock

$17.43 USD

~~$27.89 USD~~ $17.43 USD

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COSRX The Vitamin C 23 Serum 20ml

A high-potency brightening serum powered by 23% pure L-ascorbic acid to visibly improve dull tone, uneven texture, and early fine lines while delivering lightweight hydration and soothing comfort. Stabilized for consistent performance, the formula pairs Vitamin C with Tocotrienol (super Vitamin E), Sodium Hyaluronate, and Allantoin to defend against oxidative stress and support a smoother, more radiant look.

Key Benefits

23% L-ascorbic acid for visible brightening and dark spot care
Texture smoothing support for a refined, even-looking surface
Antioxidant defense with long-lasting stability for consistent results
Hydration from Sodium Hyaluronate to keep skin plump and comfortable
Soothing Allantoin to help maintain everyday tolerance

Why It Works

Vitamin C (L-ascorbic acid) is a gold-standard antioxidant that supports collagen look, brightens the appearance of uneven tone, and helps reduce visible signs of photoaging. Tocotrienol (a form of Vitamin E) works synergistically with Vitamin C to bolster oxidative defense, while humectants and skin conditioners cushion the experience so skin looks smooth and refreshed.

Ingredient Highlights

23% L-ascorbic acid – high-concentration Vitamin C for brightness and clarity
Tocotrienol (Vitamin E) – antioxidant support against free-radical stress
Sodium Hyaluronate – draws in moisture for a supple, hydrated feel
Allantoin – helps comfort and soothe the look of stressed skin

Full INCI appears on product packaging. Patch test before first use on very reactive skin.

How to Use

After cleansing and toner, apply 2–3 drops to face and neck, avoiding immediate eye area.
Press to absorb; follow with moisturizer. Use in the morning and/or evening.
When used in the AM, finish with broad-spectrum sunscreen.
Introduce gradually (2–3 times per week), then increase frequency as tolerated.

Storage tips: Keep the bottle tightly closed, away from heat and direct light. A mild scent or slight color shift can occur over time; use within the period recommended on packaging.

Recommended For

Dull, uneven-looking tone and dark spots
Rough or uneven texture in need of refinement
Early fine lines and photo-exposed skin
Normal to combination skin seeking potent yet cushioned Vitamin C care

Product Specs

Brand / Line	COSRX / The Vitamin C
Type	High-strength Vitamin C brightening serum
Size	20ml / 0.67 fl oz
Key Components	23% L-ascorbic acid, Tocotrienol, Sodium Hyaluronate, Allantoin
Skin Concerns	Dull tone, dark spots, uneven texture, early fine lines
Skin Type	All skin types; introduce gradually on sensitive skin

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COSRX Advanced The Vitamin C 23 Serum 20ml / 0.67 fl oz