COSRX The Vitamin C 23 Serum 20g – High-Strength Dark Spot Brightening Serum

Overview

The Vitamin C 23 Serum 20g is a high-strength brightening treatment designed to visibly improve dark spots, dullness and uneven skin texture.

With a concentrated 23% Vitamin C formula, it helps reduce the appearance of discoloration, smooth the look of rough patches and boost overall radiance. Lightweight yet potent, this serum is ideal as a targeted evening step in your routine for more experienced active users who want faster, clearer results.

Used consistently, it can help support a brighter, more even-toned complexion and a smoother, refined skin surface.

Key Features

• High-strength 23% Vitamin C brightening serum
• Targets dark spots, post-acne marks and overall dullness
• Helps refine the look of skin texture and pores
• Lightweight formula designed to absorb quickly
• 20g size – ideal as a focused treatment course
• Best for experienced Vitamin C users (not a beginner product)

Who It’s For

• Adults concerned with:
  • Dark spots and hyperpigmentation
  • Post-blemish marks
  • Dull, tired-looking skin
  • Uneven texture and tone
• Those who already tolerate Vitamin C or actives and want a higher concentration
• Normal, combination and oily skin types; dry or sensitive skin should introduce with caution

Not recommended for very sensitive or compromised skin, or for those new to strong actives. If you use prescription retinoids or strong exfoliating acids, consult a professional before adding this serum.

Key Benefits

• Helps visibly brighten the skin for a clearer, more radiant look
• Targets dark spots, sun damage and post-acne marks
• Supports a more even, uniform skin tone
• Assists in refining texture and visible pores for a smoother appearance
• Provides antioxidant support to help defend against environmental stressors

How to Use

Frequency (introduce slowly):

• Start with 2–3 nights per week, then gradually increase as your skin adapts.

Application:

1. In the evening, cleanse and (optionally) apply a gentle, non-exfoliating toner.
2. Apply a small amount of The Vitamin C 23 Serum to dry skin, focusing on areas with dark spots or uneven tone.
3. Gently spread and pat until fully absorbed, avoiding the immediate eye and lip area and any broken skin.
4. Follow with a hydrating serum or moisturizer to support comfort and barrier function.

Daytime care:

• Always wear a broad-spectrum SPF 30+ during the day when using Vitamin C or other brightening actives.
• Avoid layering this serum in the same routine with strong AHA/BHA peels, other high-strength Vitamin C, or retinoids unless guided by a professional.

If you experience persistent stinging, redness or peeling, reduce frequency or discontinue use and seek professional advice.

Highlighted Ingredients

• Ascorbic Acid (23%): Pure Vitamin C at a high concentration to help visibly improve dark spots and uneven tone, with antioxidant protection against environmental stressors.
• 3-O-Ethyl Ascorbic Acid: A stable Vitamin C derivative that works alongside the ascorbic acid.
• Tocopherol & Tocotrienols (Vitamin E): Antioxidants that complement Vitamin C.
• Niacinamide & Glutathione: Support a more even-looking skin tone.
• Panthenol & Sodium Hyaluronate: Help keep skin hydrated and comfortable alongside potent actives.

Full Ingredients

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.

Because formulas can change and concentrations vary, always refer to the complete ingredient list on the product packaging before use, especially if you have sensitive skin, rosacea, eczema or known allergies.

Product Specifications

• Product Name: The Vitamin C 23 Serum
• Volume: 20 g
• Product Type: High-strength Vitamin C brightening serum
• Key Functions: Brightening, dark spot care, tone-evening, texture refinement, antioxidant support
• Texture: Lightweight liquid/serum
• Skin Type: Normal, combination, oily (caution with dry or sensitive skin)
• Recommended Use: Evening treatment, introduced gradually

What’s Included

• 1 × The Vitamin C 23 Serum (20 g)