COSRX The Vitamin C 23 Serum

Introduction

Meet COSRX Vitamin C 23 serum—a potent yet wearable 23% L-ascorbic acid treatment that targets dullness, dark spots, and early lines. The formula features a unique dual-layer (light oil over serum) to slow oxidation and deliver a moisturising finish in a compact 20ml bottle.

Key Benefits

Visibly brightens and evens tone

High-strength 23% pure vitamin C helps fade dark spots and post-blemish marks while boosting overall radiance. 

Smooths texture & supports firmness

Vitamin C promotes collagen for a smoother look and helps refine rough, uneven patches over time.

Moisturising, non-greasy finish

The innovative oil-on-top layering minimises rapid oxidation and leaves a soft, comfortable finish that layers well under SPF.

Pairs with hydrators for comfort

Works seamlessly with hyaluronic acid serums or light essences to cushion potency and reduce dryness.

Budget-friendly powerhouse for experienced users

Frequently recommended as a value, high-percentage C option for those already acclimated to vitamin C. 

5 Key Features

• 23% L-ascorbic acid for fast brightening results. 

• Dual-phase bottle: oil layer on top helps slow oxidation. 

• Lightweight texture that absorbs quickly without greasiness. 

• Works with hydrating layers (e.g., hyaluronic acid) to boost comfort.

• Compact 20ml size to keep formula fresh through regular use.

Ingredients & Specifications

• Key actives: 23% L-ascorbic acid (vitamin C); often paired with moisturising and soothing helpers (e.g., hyaluronic acid, panthenol).

• Texture: Lightweight, slightly oily finish that settles quickly.

• Size: 20 ml / 0.67 fl oz.

• Skin types: Normal, combination, oily, and uneven-tone skin; beginners should patch test first. 

• Storage: Keep away from heat/sun; many users refrigerate to preserve freshness. 

• Note: Always check your box for the latest full INCI and brand guidance.

Usage Instructions

1. Prep: Cleanse, then apply a gentle hydrating toner or essence (optional).

2. Apply: Dispense 2–3 drops of COSRX Vitamin C 23 serum to dry skin; spread evenly over face and neck.

3. Layer: Follow with hydrating serum/cream (e.g., hyaluronic acid) for comfort. 

4. Protect (AM): Finish with broad-spectrum SPF 50+—essential when using vitamin C.

5. Tips: Start 3–4x/week, then daily as tolerated; avoid mixing in the same routine with strong exfoliating acids at first; store tightly capped.

Related Products:

1. Cosrx The Vitamin C 13 Serum

2. Numbuzin No.5 Goodbye Blemish Serum Vitamin C 50ml

3. Axis-Y Dark Spot Correcting Glow Serum

4. Beauty of Joseon Glow Deep Serum Rice + Alpha Arbutin